nsf 1998 complete book for pdf

NATIONAL SCIENCE FOUNDATION 1998

ENGINEERING SENIOR DESIGN PROJECTS TO AID PERSONS WITH

DISABILITIES

Edited By John D. Enderle

Brooke Hallowell

i

NATIONAL SCIENCE FOUNDATION

1998 ENGINEERING SENIOR DESIGN

PROJECTS TO AID PERSONS WITH DISABILITIES

Edited By John D. Enderle

Brooke Hallowell

Creative Learning Press, Inc. P.O. Box 320

Mansfield Center, Connecticut 06250

ii

PUBLICATION POLICY

Enderle, John Denis

National Science Foundation 1998 Engineering Senior Design Projects To Aid Persons With Disabilities / John D. Enderle, Brooke Hallowell

Includes index ISBN 0936386851

Copyright 2000 by Creative Learning Press, Inc. P.O. Box 320 Mansfield Center, Connecticut 06250

All Rights Reserved. These papers may be freely reproduced and dis-tributed as long as the source is credited.

Printed in the United States of America

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CONTENTS CONTRIBUTING AUTHORS.....................................................................................................IX

FOREWORD...................................................................................................................................XI

CHAPTER 1 INTRODUCTION..............................................................................................1

CHAPTER 2 EDUCATIONAL OUTCOMES ASSESSMENT:IMPROVING DESIGN PROJECTS TO AID PERSONS WITH DISABILITIES .........................................................13

CHAPTER 3 AN INVITATION TO COLLABORATE IN USING ASSESSMENT TO IMPROVE DESIGN PROJECTS.................................................................................................17

CHAPTER 4 ARIZONA STATE UNIVERSITY...................................................................21

VOLUNTARY-OPENING TRANSRADIAL PROSTHESIS FOR USE WITH WEIGHT TRAINING EQUIPMENT .....................................................................................................................................................................22

SHOWER CHAIR FOR A CLIENT WITH DE SANTIS CACHIONE ................................................................28

A FLY CASTING ORTHOSIS FOR A PATIENT WITH QUADRIPLEGIA......................................................30

AN EXERCISE/RANGE-OF-MOTION BIKE FOR A PATIENT WITH PARAPLEGIA...............................32

CHAPTER 5 BINGHAMTON UNIVERSITY.......................................................................35

COLLAPSIBLE ACTIVITY FRAME.............................................................................................................................36

ADJUSTABLE HEIGHT COMPUTER MONITOR..................................................................................................37

BALANCE BEAM.............................................................................................................................................................38

BED RAIL ASSIST ............................................................................................................................................................39

CART WITH BASKET.....................................................................................................................................................40

CHAIR ADJUSTMENT...................................................................................................................................................41

DOUBLE PEDAL BOARD .............................................................................................................................................42

FOLDING CHAIR ............................................................................................................................................................43

HEAD SUPPORT FOR CHAIR.....................................................................................................................................44

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THE HEAD SWITCH ......................................................................................................................................................45

ADJUSTABLE PENCIL GRIPPER ...............................................................................................................................46

PUPPET THEATRE .........................................................................................................................................................47

SCOOTER BOARD...........................................................................................................................................................48

SIT-AND-SPIN TOY FOR LARGER CHILDREN AND ADULTS .....................................................................49

STAND-PIVOT SYSTEM................................................................................................................................................50

FLOTATION BELT...........................................................................................................................................................51

TABLE FOR BENNETT BENCH..................................................................................................................................52

ADJUSTABLE MULTI-USER COMPUTER STATION ..........................................................................................53

WHEELCHAIR STORAGE RACK ..............................................................................................................................54

FOOT-PROPELLED WHEELCHAIR..........................................................................................................................55

ADJUSTABLE WALKER................................................................................................................................................56

AUTOMATIC ROCKER FOR AN EASY CHAIR ....................................................................................................58

CLIMBING WALL FOR YOUNG CHILDREN........................................................................................................60

COLLAPSIBLE CANE FOR THE BLIND ..................................................................................................................62

ELECTRONIC LOCK.......................................................................................................................................................64

A RACE CAR FOR CHILDREN...................................................................................................................................65

POOL LIFT FOR SMALL CHILD.................................................................................................................................66

PORTABLE SWIMMING POOL STAIRS ..................................................................................................................68

PRESSURE VEST..............................................................................................................................................................70

BLOW-STRAW UNIVERSAL REMOTE CONTROL .............................................................................................72

WHEELCHAIR SWING .................................................................................................................................................74

CHAPTER 6 DUKE UNIVERSITY.........................................................................................77

SENSORY STIMULATION ACTIVITY CENTER....................................................................................................78

CHILD-FRIENDLY ACTIVITY TIMER ......................................................................................................................82

COMPUTER GAMES FOR LEARNING JOYSTICK CONTROL ........................................................................84

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AUTOMATIC FEEDER MODIFICATIONS AND WHEELCHAIR-TO-BED TRANSFER APPARATUS.....................................................................................................................................................................86

POOL CHAIR ....................................................................................................................................................................88

CHAPTER 7 MANHATTAN COLLEGE...............................................................................91

AUTOMATED DIE ROLLING DEVICE.....................................................................................................................92

VENTILATING SYSTEM FOR A NURSING HOME GREENHOUSE .............................................................94

MODIFICATIONS AND ENHANCEMENTS TO A CONSOLE TV STAND..................................................96

ENHANCED ELECTRONIC TV CONTROL SYSTEM .........................................................................................97

A TABLE-SIZE ROULETTE WHEEL..........................................................................................................................98

A PNEUMATIC TV CONTROL SYSTEM ................................................................................................................99

A PNEUMATIC TV CONTROL SYSTEM .................................................................................................................100

CHAPTER 8 MISSISSIPPI STATE UNIVERSITY .............................................................103

TRAIL READY UTILITY VEHICLE FOR PEOPLE WITH PHYSICAL DISABILITIES.................................104

ROLLER WALKER WITH SPRING-ACTIVATED BRAKING SYSTEM FOR A PATIENT WITH CEREBRAL PALSY..........................................................................................................................................................106

WHEELCHAIR SEAT WITH AIR ROTATION TO RELIEVE PRESSURE ......................................................108

CHAPTER 9 NEW JERSEY INSTITUTE OF TECHNOLOGY .........................................111

PC INTERFACE ENVIRONMENTAL CONTROL UNIT.....................................................................................112

SPEECH RECOGNITION FOR AN ENVIRONMENTAL CONTROL UNIT .................................................113

SPEECH RECOGNITION FOR ENVIRONMENTAL CONTROL OF A WHEELCHAIR ...........................114

CHAPTER 10 NORTH CAROLINA STATE UNIVERSITY ...........................................115

EVALUATION AND TREATMENT TABLE............................................................................................................116

BICYCLE CART FOR A CHILD ...................................................................................................................................118

CHAPTER 11 NORTH DAKOTA STATE UNIVERSITY................................................121

VOICE RECOGNITION CLOCK..................................................................................................................................122

ALARM CLOCK FOR INDIVIDUALS WITH HEARING IMPAIRMENT.......................................................124

CAMERA FOR INDIVIDUALS WITH VISUAL IMPAIRMENT OR BLINDNESS........................................126

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EXERCISE ENHANCER ...............................................................................................................................................128

FORCE MEASUREMENT FOR PROSTHETICS......................................................................................................130

VOICE SPECTRUM ANALYSIS...................................................................................................................................132

CHAPTER 12 NORTHERN ILLINOIS UNIVERSITY .....................................................135

VOICE PITCH ANALYZER ..........................................................................................................................................136

A DSP-BASED WIRELESS INFANT MONITORING DEVICE FOR INDIVIDUALS WITH HEARING IMPAIRMENT...................................................................................................................................................................138

CHAPTER 13 STATE UNIVERSITY OF NEW YORK AT BUFFALO ..........................141

OPHTHALMOLOGIST’S OPTICAL LENS HOLDER FOR SLIT LAMP EYE EXAMS................................142

WHEELCHAIR STEP NEGOTIATOR........................................................................................................................144

BOOK RETRIEVER ..........................................................................................................................................................146

PORTABLE LIFT FOR WHEELCHAIRS ...................................................................................................................148

ASSISTIVE GLOVE: A MECHANICAL EXOSKELETON TO AUGMENT HAND STRENGTH AND CONTROL..........................................................................................................................................................................150

EMERGENCY VACUUM-PACKED NECK SUPPORT.........................................................................................152

SHOWERHEAD-ATTACHABLE SOAP AND SHAMPOO DISPENSER .......................................................154

AUTOMATED GARBAGE BAG SEALER ................................................................................................................156

ADJUSTABLE ANKLE SUPPORT TO RELIEVE COMPRESSIVE FORCES....................................................158

ASSISTIVE CAR SEAT TO FACILITATE...................................................................................................................160

ENTRY AND EXIT...........................................................................................................................................................160

EASY PUMP FUELING DEVICE FOR SELF- SERVICE GASOLINE DISPENSING.....................................162

STOWABLE WHEELCHAIR UMBRELLA...............................................................................................................164

WHEELCHAIR PROPULSION DEVICE...................................................................................................................166

HEAT EXCHANGER TO PREVENT OR REDUCE EFFECTS OF EXERCISE-INDUCED ASTHMA......168

UTENSIL HOLDER HAND BRACE...........................................................................................................................170

CHAPTER 14 TEXAS A&M UNIVERSITY........................................................................173

OPTIMIZATION OF ENVIRONMENTAL CONTROL TO FIT A SMALL LIVING SPACE.......................174

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AN ARM BRACE FOR USE BY PATIENTS WITH LOWER BACK TROUBLE .............................................178

AUGMENTATIVE COMMUNICATION DEVICE..................................................................................................180

CLOTHES DRYER WITH FRONT MOUNTED CONTROLS FOR HANDICAPPED ACCESS................182

CHAPTER 15 UNIVERSITY OF ALABAMA AT BIRMINGHAM................................187

SHOWER CHAIRS FOR INDIVIDUALS WITH CEREBRAL PALSY...............................................................188

FOREARM MOTION/TORQUE ANALYZER........................................................................................................192

WHEELCHAIR HEADREST DESIGN.......................................................................................................................194

CHAPTER 16 UNIVERSITY OF TENNESSEE AT CHATTANOOGA.........................197

BICYCLE FOR A SMALL CHILD ................................................................................................................................198

COMPUTER WORKSTATION.....................................................................................................................................200

SUPPORTIVE DINING CHAIR....................................................................................................................................202

LAPTOP SUPPORT .........................................................................................................................................................204

PRINTER SUPPORT........................................................................................................................................................206

CHAPTER 17 UNIVERSITY OF TOLEDO.........................................................................209

ADAPTATION OF A RIDING LAWNMOWER FOR A PERSON WITH PARAPLEGIA...........................210

DRINKING SYSTEM FOR PERSONS WITH QUADRIPLEGIA.........................................................................216

ASSISTIVE DEVICE TO START A PULL-START LAWNMOWER...................................................................218

ASSISTIVE DEVICE TO OPEN AND CLOSE LARGE JARS................................................................................220

REACHER DEVICE ........................................................................................................................................................222

WHEELCHAIR BICYCLE-TYPE ATTACHMENT.................................................................................................224

TEMPERATURE CONTROL SHOWER UNIT........................................................................................................226

CHAPTER 18 UTAH STATE UNIVERSITY ......................................................................229

AUTOMATIC ROCKING BENCH SWING ..............................................................................................................230

TRAILER-MOUNTED LIFT SYSTEM FOR HORSEBACK RIDING..................................................................232

REMOTE-CONTROLLED MOTORIZED TOY VEHICLE....................................................................................234

THE SIGHTSEER: ADAPTED OFF-ROAD VEHICLE...........................................................................................236

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CHILD’S JOYSTICK-CONTROLLED GO-CART ....................................................................................................238

WHEELCHAIR DYNAMIC SEATING SYSTEM ....................................................................................................240

THREE-WHEELED HAND POWERED CYCLE ....................................................................................................242

DUAL ADAPTIVE RECUMBENT TRICYCLE.........................................................................................................244

CHAPTER 19 WAYNE STATE UNIVERSITY...................................................................247

WHEELCHAIR MOUNTING CLAMP FOR A LAPTOP COMPUTER ............................................................248

ADJUSTABLE PLATFORM FOR AUGMENTATIVE COMMUNICATION DEVICES................................252

MOUTH STICK DOCKING STATION.......................................................................................................................254

LAPTOP COMPUTER CARRYING SYSTEM..........................................................................................................256

LOWER EXTREMITY EXERCISE SYSTEM..............................................................................................................258

CHAPTER 20 WRIGHT STATE UNIVERSITY.................................................................261

BILATERAL ACOUSTIC TRAINER ...........................................................................................................................262

ENVIRONMENTAL CONTROL UNIT .....................................................................................................................266

ADJUSTABLE CHAIR HEIGHT ..................................................................................................................................268

MULTI-FUNCTION SPEECH THERAPY APPARATUS .....................................................................................270

AUTOMATIC JAR OPENER.........................................................................................................................................272

RTA BUS ANNUNCIATOR SYSTEM FOR PERSONS WITH VISUAL IMPAIRMENTS ...........................274

CHAPTER 21 INDEX ..............................................................................................................275

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CONTRIBUTING AUTHORS Susan M. Blanchard, Biological and Agricultural Engi-neering Department, North Carolina State University, Raleigh, North Carolina 27695-7625

Laurence N. Bohs, Department of Biomedical Engineer-ing, Duke University, Durham, North Carolina 27708-0281

Richard Culver, Mechanical Engineering, The Watson School, SUNY Binghamton, Binghamton, NY 13902-6000 Alan W. Eberhardt, University Of Alabama At Bir-mingham, Department of Materials and Mechanical Engineering, BEC 254, 1150 10th Ave. S., Birmingham, Alabama, 35294-4461

John Enderle, Electrical & Computer Engineering, Uni-versity of Connecticut, Storrs, CT 06269-2157 Daniel L. Ewert, Department of Electrical Engineering, North Dakota State University, Fargo, North Dakota 58105

Bertram N. Ezenwa, Department of Mechanical Engi-neering, School of Medicine, Department of Physical Medicine and Rehabilitation, Wayne State University 261 Mack Blvd Detroit MI 48201 Marvin G. Fifield, Center for Persons with Disabilities, Utah State University, Logan, Utah 84322-4130 Jacob S. Glower, Department of Electrical Engineering, North Dakota State University, Fargo, North Dakota 58105 Jiping He, Chemical, Bio, & Materials Engineering, Arizona State University, Tempe, AZ 85287-6006 Daniel W. Haines, Dept. of Mechanical Engineering, Manhattan College, 4513 Manhattan College Park-way, Bronx, NY 10471 Brooke Hallowell, School of Hearing and Speech Sci-ences, Lindley Hall 208, Ohio University, Athens, OH 45701

Mohamed Samir Hefzy, Department of Mechanical En-gineering, University Of Toledo, Toledo, Ohio, 43606 William Hyman, Bioengineering Program, Texas A&M University, College Station, TX 77843 Richard K. Irey , Department of Mechanical Engineer-ing, University Of Toledo, Toledo, Ohio, 43606

Xuan Kong, Department of Electrical Engineering, Northern Illinois University, DeKalb, IL 60115 Gary M. McFadyen, T.K. Martin Center for Technology and Disability, P.O. Box 9736, Mississippi State Uni-versity, Mississippi State, MS 39762

Edward H. McMahon, College of Engineering and Computer Science, University Of Tennessee At Chat-tanooga Chattanooga, TN 37403

Joseph C. Mollendorf, Mechanical and Aerospace En-gineering, State University of New York at Buffalo, Buffalo, NY 14260 Nagi Naganathan, Department of Mechanical, Indus-trial and Manufacturing Engineering, University Of Toledo, Toledo, Ohio, 43606-3390

Chandler Phillips, Biomedical and Human Factors En-gineering, Wright State University, Dayton, OH 45435 Frank Redd, Mechanical & Aerospace Engineering, Utah State University, Logan, Utah 84322-4130 Stanley S. Reisman, Department of Electrical and Com-puter Engineering, New Jersey Institute Of Technol-ogy, Newark, New Jersey 07102

David B. Reynolds, Biomedical and Human Factors Engineering, Wright State University, Dayton, OH 45435

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Roger P. Rohrbach, Biological and Agricultural Engi-neering Department, North Carolina State University, Raleigh, North Carolina 27695-7625 Mansour Tahernezhadi, Department of Electrical En-gineering, Northern Illinois University, DeKalb, IL 60115 Val Tareski, Department of Electrical Engineering, North Dakota State University, Fargo, North Dakota 58105 Gary Yamaguchi, Chemical, Bio, & Materials Engineer-ing, Arizona State University, Tempe, AZ 85287-6006

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FOREWORD Welcome to the tenth annual issue of the National Science Foundation Engineering Senior Design Pro-jects to Aid Persons with Disabilities. In 1988, the National Science Foundation (NSF) began a program to provide funds for student engineers at universities throughout the United States to construct custom de-signed devices and software for individuals with dis-abilities. Through the Bioengineering and Research to Aid the Disabled (BRAD) program of the Emerging Engineering Technologies Division of NSF,1 funds were awarded competitively to 16 universities to pay for supplies, equipment and fabrication costs for the design projects. A book entitled, NSF 1989 Engineer-ing Senior Design Projects to Aid the Disabled was pub-lished in 1989, reporting on the projects that were funded during the first year of this effort.

In 1989, the BRAD program of the Emerging Engi-neering Technologies Division of NSF increased the number of universities funded to 22 in 1989. Fol-lowing completion of the 1989-1990 design projects, a second book was published, describing these projects, entitled, NSF 1990 Engineering Senior Design Projects to Aid the Disabled .

North Dakota State University (NDSU) Press pub-lished the following three issues. NSF 1991 Engineer-ing Senior Design Projects to Aid the Disabled described the almost 150 projects carried out by students at 20 universities across the United States during the aca-demic year 1990-91. NSF 1992 Engineering Senior De-sign Projects to Aid the Disabled presented the almost 150 projects carried out by students at 21 universities across the United States during the 1991-92 academic year. The fifth issue described 91 projects carried out by students at 21 universities across the United States during the 1992-93 academic year.

Creative Learning Press, Inc. has published the suc-ceeding volumes. NSF 1994 Engineering Senior Design

1 In January of 1994, the Directorate for Engineering (ENG) was restructured. This program is now in the Division of Bioengineering and Environmental Sys-tems, Biomedical Engineering & Research Aiding Per-sons with Disabilities Program.

Projects to Aid the Disabled, published in 1997, de-scribed 94 projects carried out by students at 19 uni-versities across the United States during the academic 1993-94 year.

NSF 1995 Engineering Senior Design Projects to Aid the Disabled , published in 1998, described 124 projects carried out by students at 19 universities during the 1994-95 academic year.

NSF 1996 Engineering Senior Design Projects to Aid Per-sons With Disabilities, published in 1999, presented 93 projects carried out by students at 12 universities dur-ing the 1995-96 academic year.

The ninth issue, NSF 1997 Engineering Senior Design Projects to Aid Persons with Disabilities, published in 2000, included 124 projects carried out by students at 19 universities during the 1994-95 academic year.

This book, funded by the NSF, describes and docu-ments the NSF-supported senior design projects dur-ing the tenth year academic year of this effort, 1997-98. Each chapter, except for the first three, describes activity at a single university, and was written by the principal investigator(s) at that university, and re-vised by the editors of this publication. Individuals wishing more information on a particular design should contact the designated supervising principal investigator. An index is provided so that projects may be easily identified by topic.

It is hoped that this book will enhance the overall quality of future senior design projects directed to-ward persons with disabilities by providing exam-ples of previous projects, and by motivating faculty at other universities to participate because of the poten-tial benefits to students, schools, and communities. Moreover, the new technologies used in these projects will provide examples in a broad range of applica-tions for new engineers. The ultimate goal of both this publication and all the projects that were built under this initiative is to assist individuals with dis-abilities in reaching their maximum potential for en-joyable and productive lives.

This NSF program has brought together individuals with widely varied backgrounds. Through the rich-

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ness of their interests, a wide variety of projects were completed, and are in use. A number of different technologies were incorporated in the design projects, to maximize the impact of each device on the individ-ual for whom it was developed.

A two-page project description format is generally used in this text. Each project is introduced with a nontechnical description, followed by a summary of impact that illustrates the effect of the project on an individual’s life. A detailed technical description then follows. Photographs of the devices and other important components are incorporated throughout the manuscript.

None of the faculty received financial remuneration for supervising the building of devices or writing software within this program. Each participating university typically has made a five-year commitment to the program.

Sincere thanks are extended to Dr. Allen Zelman, a former Program Director of the NSF BRAD program, for being the prime enthusiast behind this initiative. Additionally, thanks are extended to Drs. Peter G. Ka-tona, Karen M. Mudry, Fred Bowman and Gil Devey, former and current NSF Program Directors of the Biomedical Engineering and Research to Aid Persons with Disabilities Programs, who have continued to support and expand the program.

We acknowledge and thank Ms. Shari Valenta for the cover illustration and the artwork throughout the book, drawn from her observations at the Children's Hospital Accessibility Resource Center in Denver, Colorado. We also acknowledge and thank Mr. Wil-liam Pruehsner for technical illustrations and Dr. Leon Anderson, Ms. Lollie Vaughan, Ms. Leetal Cu-perman, Ms. Kirsten Carr, Ms. Carrie Brannon, and Mrs. Jean Hallowell for editorial assistance.

The information in this publication is not restricted in any way. Individuals are encouraged to use the pro-ject descriptions in the creation of future design pro-jects for persons with disabilities. The NSF and edi-tors make no representations or warranties of any kind with respect to these design projects, and spe-cifically disclaim any liability for any incidental or consequential damages arising from the use of this publication. Faculty members using the book as a

guide should exercise good judgment when advising students.

Readers familiar with previous editions of this book will note that John Enderle moved from North Dakota State University to the University of Connecticut in 1995. With that move, annual publications also moved from NDSU Press to Creative Learning Press Inc. in 1997. During 1994, Enderle also served as NSF Program Director for the Biomedical Engineering & Research Aiding Persons with Disabilities Program while on a leave of absence from NDSU.

Brooke Hallowell is a faculty member in the School of Hearing and Speech Sciences at Ohio University. Hallowell’s primary area of expertise is in neurogenic communication disorders. She has a long history of collaboration with colleagues in biomedical engineer-ing, in curriculum development, teaching, assess-ment, and research.

The editors welcome any suggestions as to how this review may be made more useful for subsequent yearly issues. Previous editions of this book are available for viewing at the WEB Site for this project:

http://nsf-pad.bme.uconn.edu/.

John D. Enderle, Ph.D., Editor Department of Electrical & Systems Engineering 260 Glenbrook Road, U-157 University of Connecticut Storrs, Connecticut 06269-2157 Voice: (860) 486-5521 FAX: (860) 486-2447 E-mail: [email protected] Brooke Hallowell, Ph.D., Editor School of Hearing and Speech Sciences Lindley Hall 208 Ohio University Athens, OH 45701 Voice: (740) 593-1356 FAX: (740) 593-0287 E-mail: [email protected]

December 2000

NATIONAL SCIENCE FOUNDATION

1998 ENGINEERING SENIOR DESIGN

PROJECTS TO AID PERSONS WITH DISABILITIES

1

CHAPTER 1 INTRODUCTION

John Enderle and Brooke Hallowell

Devices and software to aid persons with disabilities often need custom modification, are prohibitively ex-pensive, or nonexistent. Many persons with disabili-ties do not have access to custom modification of available devices and other benefits of current tech-nology. Moreover, when available, engineering and support salaries often make the cost of custom modi-fications beyond the reach of the persons who need them.

In 1988, the National Science Foundation (NSF), through its Emerging Engineering Technologies Divi-sion, initiated a program to support student engineers at universities throughout the United States design-ing and building devices for persons with disabilities. Since its inception, this NSF program (originally called Bioengineering and Research to Aid the Dis-abled) has enhanced educational opportunities for students and improved the quality of life for indi-viduals with disabilities. Students and university faculty provide, through their Accreditation Board for Engineering and Technology (ABET) accredited sen-ior design class, engineering time to design and build the device or software. The NSF provides funds, com-petitively awarded to universities for supplies, equipment and fabrication costs for the design pro-jects.

Outside of the NSF program, students are typically involved in design projects that incorporate academic goals for solid curricular design experiences, but that do not necessarily enrich the quality of life for per-sons other than, perhaps, the students themselves. For instance, students might design and construct a stereo receiver, a robotic unit that performs a house-hold chore, or a model racecar.

Under this NSF program, engineering design stu-dents are involved in projects that result in original

devices, or custom modifications of devices, that im-prove the quality of life for persons with disabilities. The students have opportunities for practical and creative problem solving to address well-defined needs, and persons with disabilities receive the prod-ucts of that process. There is no financial cost in-curred by the persons served in this program. Upon completion, the finished project becomes the property of the individual for whom it was designed.

The emphases of the program are to:

• Provide disabled children and adults stu-dent-engineered devices or software to im-prove their quality of life and provide greater for self-sufficiency;

• Enhance the education of student engineers by designing and building a device or soft-ware that meets a real need; and

• Allow the university an opportunity for unique service to the local community.

Local school districts and hospitals participate in the effort by referring interested individuals to the pro-gram. A single student or a team of students specifi-cally designs each project for an individual or a group of individuals with a similar need. Examples of projects completed in years past include a laser-pointing device for people who cannot use their hands, a speech aid, a behavior modification device, a hands-free automatic answering and hang-up tele-phone system, and an infrared beacon to help a blind person move around a room. The students participat-ing in this project have been singularly rewarded through their activity with persons with disabilities, and justly have experienced a unique sense of pur-pose and pride in their accomplishment.

2 NSF 1998 Engineering Senior Design Projects to Aid Persons with Disabilities

The Current Book This book describes the NSF supported senior design projects during the tenth year of this effort during the academic year 1997-98. The purpose of this publica-tion is twofold. First, it is to serve as a reference or handbook for future senior design projects. Students are exposed to this unique body of applied informa-tion on current technology in this and previous edi-tions of this book. This provides an even broader education than typically experienced in an under-graduate curriculum, especially in the area of reha-bilitation design. Many technological advances originate from work in the space, defense, entertain-ment and communications industry. Few of these advances have been applied to the rehabilitation field, making the contributions of this NSF program all the more important.

Secondly, it is hoped that this publication will serve to motivate students, graduate engineers and others to work more actively in rehabilitation. This will ideally lead to an increased technology and knowledge base to effectively address the needs of persons with disabilities. This introduction provides background material on the book, elements of design, and highlights the engi-neering design experiences at three universities that have participated in this effort.

After the introduction, 17 chapters follow, with each chapter devoted to one participating school. At the start of each chapter, the school and the principal in-vestigator(s) are identified. Each project description is written using the following format. On page one, the individuals involved with the project are identified, including the student(s), the professor(s) who super-vised the project, and key professionals involved in the daily lives of the individual for whom the project has been developed. A brief nontechnical description of the project follows with a summary of how the pro-ject has improved a person’s quality of life. A photo-graph of the device or the device modification is usu-ally included. Next, a technical description of the de-vice or device modification is given, with parts speci-fied only if they are of such a special nature that the project could not otherwise be fabricated. An ap-proximate cost of the project is provided, excluding personnel costs.

Most projects are described in two pages. However, the first or last project in each chapter is usually sig-nificantly longer and contains more analytic content. Individuals wishing more information on a particular design should contact the designated supervising principal investigator.

Some of the projects described are custom modifica-tions of existing devices, modifications that would be prohibitively expensive were it not for the student en-gineers and this NSF program. Other projects are unique one-of-a-kind devices wholly designed and constructed by the student for the disabled individ-ual.

Engineering Design As part of the accreditation process for university en-gineering programs, students are required to complete a minimum number of design credits in their course of study, typically at the senior level.1, 2 Many call this the capstone course. Engineering design is a course or series of courses that brings together concepts and principles that students learn in their field of study. It involves the integration and extension of material learned throughout an academic program to achieve a specific design goal. Most often, the student is ex-posed to system-wide analysis, critique and evalua-tion. Design is an iterative decision making process in which the student optimally applies previously learned material to meet a stated objective.

There are two basic approaches to teaching engineer-ing design, the traditional or discipline-dependent approach, and the holistic approach. The traditional approach involves reducing a system or problem into separate discipline-defined components. This ap-proach minimizes the essential nature of the system as a holistic or complete unit, and often neglects the interactions that take place between the components. The traditional approach usually involves a sequen-

1 Accrediting Board for Engineering and Technology (1999). Accreditation Policy and Procedure Manual Effective for Evaluations for the 2000-2001 Accredita-tion Cycle. ABET: Baltimore, MD. 2 Accrediting Board for Engineering and Technology (2000). Criteria for Accrediting Engineering Programs. ABET: Baltimore, MD.

Chapter 1: Introduction 3

tial, iterative approach to the system or problem, and emphasizes simple cause-effect relationship.

A more holistic approach to engineering design is be-coming increasingly feasible with the availability of powerful computers and engineering software pack-ages, and the integration of systems theory, which addresses interrelationships among system compo-nents as well as human factors. Rather than parti-tioning a project based on discipline-defined compo-nents, designers partition the project according to the emergent properties of the problem.

A design course provides opportunities for problem solving relevant to large-scale, open- ended, complex, and sometimes ill-defined systems. The emphasis of design is not on learning new material. Typically, there are no required textbooks for the design course, and only a minimal number of lectures are presented to the student. Design is best described as an indi-vidual study course where the student:

• Selects the device or system to design

• Writes specifications

• Creates a paper design

• Analyzes the paper design

• Constructs the device

• Evaluates the device

• Documents the design project

Project Selection In a typical NSF design project, the student meets with the client (a person with a disability and/or a client coordinator) to assess needs and to help iden-tify a useful project. Often, the student meets with many clients before finding a project for which his or her background is suitable.

After selecting a project, the student then writes a brief description of the project for approval by the faculty supervisor. Since feedback at this stage of the process is vitally important for a successful project, students usually meet with the client once again to review the project description.

Projects are often undertaken by teams of students. One or more members of a team meet with one or more clients before selecting a project. After project selec-tion, the project is partitioned by the team into logical parts, and each student is assigned one of these parts. Usually, a team leader is elected by the team to ensure that project goals and schedules are satisfied. A team of students generally carries out multiple projects.

Project selection is highly variable depending on the university, and the local health care facilities. Some universities make use of existing technology to de-velop projects to aid the disabled by accessing data-bases such as ABLEDATA. ABLEDATA includes in-formation on types of assistive technology, consumer guides, manufacturer directories, commercially avail-able devices, and one-of-a-kind customized devices. In total, this database has over 23,000 products from 2,600 manufactures and is available from:

http://www.abledata.com or

(800) 227-0216

More information about this NSF program is avail-able at:

http://nsf-pad.bme.uconn.edu

Specifications One of the most important parts of the design process is determining the specifications, or requirements that the design project must fulfill. There are many differ-ent types of hardware and software specifications.

Prior to the design of a project, a statement as to how the device will function is required. Operational specifications are incorporated in determining the problem to be solved. Specifications are defined such that any competent engineer is able to design a device that will perform a given function. Specifications de-termine the device to be built, but do not provide in-formation about how the device is built. If several en-gineers design a device from the same specifications, all of the designs would perform within the given tol-erances and satisfy the requirements; however, each design would be different. No manufacturer's name or components are stated in specifications. For ex-ample, specifications do not list electronic compo-nents or even a microprocessor since use of these


components implies that a design choice has been made.

If the design project involves modifying an existing device, the modification should be fully described in as much detail as possible in the specifications. Spe-cific components of the device, such as microproces-sors, LEDs, and electronic parts, should be described. Descriptive detail is appropriate because it defines the environment to which the design project must in-terface. However, the specifications for the modifica-tion should not provide any information about how the device is to be built.

Specifications are usually written in a report that qualitatively describes the project as completely as possible, and how the project will improve the life of an individual. It is also important to explain the mo-tivation for carrying out the project. The following is-sues are addressed in the specifications:

• What will the finished device do?

• What is unusual about the device?

Specifications include a technical description of the device, and all of the facts and figures needed to com-plete the design project. The following are examples of important items included in technical specifica-tions.

Electrical Parameters

interfaces voltages impedances gains power output power input ranges current capabilities harmonic distortion stability accuracy precision power consumption

Mechanical

size weight durability

accuracy precision vibration

Environmental

location temperature range moisture dust

Paper Design and Analysis The next phase of the design is the generation of pos-sible solutions to the problem based on the specifica-tions, and selection of the optimal solution. This in-volves creating a paper design for each of the solu-tions and evaluating performance based on the speci-fications. Since design projects are open-ended, many solutions exist, solutions that often require a multid-isciplinary system or holistic approach for a success-ful and useful product. This stage of the design proc-ess is typically the most challenging because of the creative aspect to generating problem solutions.

The specifications previously described are the cri-teria for selecting the best design solution. In many projects, some specifications are more important than others, and trade-offs between specifications may be necessary. In fact, it may be impossible to design a project that satisfies all of the design specifications. Specifications that involve some degree of flexibility are helpful in reducing the overall complexity, cost and effort in carrying out the project. Some specifica-tions are absolute and cannot be relaxed.

Most projects are designed in a top-down approach similar to the approach of writing computer software by first starting with a flow chart. After the flow chart or block diagram is complete, the next step involves providing additional details to each block in the flow-chart. This continues until sufficient detail exists to determine whether the design meets the specifications after evaluation.

To select the optimal design, it is necessary to analyze and evaluate the possible solutions. For ease in analysis, it is usually easiest to use computer soft-ware. For example, PSpice, a circuit analysis pro-gram, easily analyzes circuit analysis problems. Other situations require that a potential design pro-ject solution be partially constructed or breadboarded


for analysis and evaluation. After analysis of all pos-sible solutions, the optimal design selected is the one that meets the specifications most closely.

Construction and Evaluation of the Device After selecting the optimal design, the student then constructs the device. The best method of construc-tion is to build the device module by module. By building the project in this fashion, the student is able to test each module for correct operation before add-ing it to the complete device. It is far easier to elimi-nate problems module by module than to build the entire project, and then attempt to eliminate problems.

Design projects should be analyzed and constructed with safety as one of the highest priorities. Clearly, the design project that fails should fail in a safe man-ner, a fail-safe mode, without any dramatic and harm-ful outcomes to the client or those nearby. An exam-ple of a fail-safe mode of operation for an electrical device involves grounding the chassis, and using ap-propriate fuses; thus if ever a 120-V line voltage short circuit to the chassis should develop, a fuse would blow and no harm to the client would occur. Devices should also be protected against runaway conditions during the operation of the device, and also during periods of rest. Failure of any critical components in a device should result in the complete shutdown of the device.

After the project has undergone laboratory testing, it is then tested in the field with the client. After the field test, modifications are made to the project, and then the project is given to the client. Ideally, the de-sign project in use by the disabled person should be periodically evaluated for performance and useful-ness after the project is complete. Evaluation typically occurs, however, when the device no longer performs adequately for the disabled person, and is returned to the university for repair or modification. If the repair or modification is simple, a university technician will handle the problem. If the repair or modification is more extensive, another design student is assigned to the project to handle the problem as part of their de-sign course requirements.

Documentation Throughout the design process, the student is re-quired to document the optimal or best solution to the problem through a series of required written assign-ments. For the final report, documenting the design

project involves integrating each of the required re-ports into a single final document. While this should be a simple exercise, it is usually a most vexing and difficult endeavor. Many times during the final stages of the project, some specifications are changed, or extensive modifications to the ideal paper design are necessary.

Most universities also require that the final report be professionally prepared using desktop publishing software. This requires that all circuit diagrams and mechanical drawings be professionally drawn. Illus-trations are usually drawn with computer software, such as OrCAD or AutoCAD.

The two-page reports within this publication are not representative of the final reports submitted for de-sign course credit, and in fact, are a summary of the final report. A typical final report for a design project is approximately 30 pages in length, and includes ex-tensive analysis supporting the operation of the de-sign project. Usually, photographs of the device are not included in the final report since mechanical and electrical diagrams are more useful to the engineer to document the device.

The next three sections illustrate different approaches to the design course experience. At Texas A&M Uni-versity, the students work on many small design pro-jects during the two-semester senior design course se-quence. At North Dakota State University, students work on a single project during the two-semester sen-ior design course sequence. At the University of Con-necticut, students are involved in distance learning and a WWW based approach.

Texas A&M University Engineering Design Experiences The objective of the NSF program at Texas A&M Uni-versity is to provide senior bioengineering students an experience in the design and development of reha-bilitation devices and equipment to meet explicit cli-ent needs identified at several off campus rehabilita-tion and education facilities. Texas A&M has par-ticipated in the NSF program for six years. The stu-dents meet with therapists and/or special education teachers for problem definition under faculty supervi-sion. This program provides very significant “real world” design experiences, emphasizing completion


of a finished product. Moreover, the program brings needed technical expertise that would otherwise not be available to not-for-profit rehabilitation service providers. Additional benefits to the participating students involve their development of an apprecia-tion of the problems of disabled persons, motivation toward rehabilitation engineering as a career path, and recognition of the need for more long-term re-search to address the problems for which today's de-signs are only an incomplete solution.

Texas A&M University’s program involves a two-course capstone design sequence, BIEN 441 and 442. BIEN 441 is offered during the Fall and Summer se-mesters, and BIEN 442 is offered during the Spring semester. The inclusion of the summer term allows a full year of ongoing design activities. Students are al-lowed to select a rehabilitation design project, or an-other general bioengineering design project.

The faculty at Texas A&M University involved with the rehabilitation design course have worked in col-laboration with the local school districts, community rehabilitation centers, residential units of the Texas Department of Mental Health and Mental Retardation (MHMR), community outreach programs of Texas MHMR, and individual clients of the Texas Rehabili-tation Commission and Texas Commission for the Blind.

Appropriate design projects are identified in group meetings between the staff of the collaborating agency, the faculty, and the participating under-graduate students enrolled in the design class. In addition, one student is employed in the design labo-ratory during the summer to provide logistical sup-port, as well as pursue his or her own project. Each student is required to participate in the project defi-nition session, which adds to the overall design ex-perience. The meetings take place at the beginning of each semester, and periodically thereafter as projects are completed and new ones identified.

The needs expressed by the collaborating agencies of-ten result in projects that vary in complexity and re-quired duration. To meet the broad spectrum of needs, simpler projects are accommodated by requir-ing rapid completion, at which point the students move on to another project. More difficult projects in-volve one or more semesters, or even a year's effort; these projects are the ones that typically require more

substantial quantitative and related engineering analysis. Projects are carried out by individual stu-dents or a team of two.

Following the project definition, the students proceed through the formal design process of brainstorming, clarification of specifications, preliminary design, re-view with the collaborating agency, design execution and safety analysis, documentation, prerelease de-sign review, and delivery and implementation in the field. The execution phase of the design includes identifying and purchasing necessary components and materials, arranging for any fabrication services that may be necessary, and obtaining photography for their project reports. Throughout each phase of the project, the faculty supervises the work, as well as the teaching assistants assigned to the rehabilitation engineering laboratory. These teaching assistants are paid with university funds. The students also have continued access to the agency staffs for clarification or revision of project definitions, and review of pre-liminary designs. The latter is an important aspect of meeting real needs with useful devices. In addition to individual and team progress, the rehabilitation en-gineering group meets as a group to discuss design ideas and project progress, and to plan further visits to the agencies.

One challenging aspect of having students be respon-sible for projects that are eagerly anticipated by the in-tended recipient is the variable quality of student work, and the inappropriateness of sending inade-quate projects into the field. This potential problem is resolved at Texas A&M University by continuous pro-ject review, and by requiring that the project be re-vised and reworked until it meets faculty approval.

At the end of each academic year, the faculty and the personnel from each collaborating agency assess which types of projects met with the greatest success in achieving useful delivered devices. This review has provided ongoing guidance in the selection of fu-ture projects. The faculty also maintains continuous contact with agency personnel with respect to ongo-ing and past projects that require repair or modifica-tion. In some instances, repairs are assigned as short-term projects to currently participating students. This provides an excellent lesson in the importance of adequate documentation.


Feedback from participating students is gathered each semester using the Texas A&M University stu-dent “oppinionaire” form as well as personal dis-cussion. The objective of the reviews is to obtain stu-dents’ assessment of the educational value of the re-habilitation design program, the adequacy of the re-sources and supervision, and any suggestions for improving the process.

North Dakota State University Engineering Design Experience North Dakota State University (NDSU) has partici-pated in this program for six years. All senior electri-cal engineering students at NDSU are required to complete a two-semester senior design project as part of their study. These students are partitioned into faculty-supervised teams of four to six students. Each team designs and builds a device for a particular dis-abled individual within eastern North Dakota or western Minnesota.

During the early stages of NDSU's participation in projects to aid the disabled, a major effort was under-taken to develop a complete and workable interface between the NDSU electrical engineering department and the community of persons with disabilities to identify potential projects. These organizations are the Fargo Public School System, NDSU Student Ser-vices and the Anne Carlson School. NDSU students visit potential clients or their supervisors to identify possible design projects at one of the cooperating or-ganizations. All of the senior design students visit one of these organizations at least once. After the site visit, the students write a report on at least one poten-tial design project, and each team selects a project to aid a particular individual.

The process of a design project is implemented in two parts. During the first semester of the senior year, each team writes a report describing the project to aid an individual. Each report consists of an introduc-tion to the project establishing the need for the project. The body of the report describes the device; a com-plete and detailed engineering analysis is included to establish that the device has the potential to work. Almost all of the NDSU projects involve an electronic circuit. Typically, devices that involve an electrical circuit are analyzed using PSpice, or another software analysis program. Extensive testing is undertaken on subsystem components using breadboard circuit lay-outs to ensure a reasonable degree of success before

writing the report. Circuits are drawn for the report using OrCAD, a CAD program. The OrCAD draw-ings are also used in the second phase of design, which allows the students to bring a circuit from the schematic to a printed circuit board with relative ease.

During the second semester of the senior year, each team builds the device to aid an individual. This first involves breadboarding the entire circuit to establish the viability of the design. After verification, the stu-dents build a printed circuit board(s) using OrCAD, and then finish the construction of the project using the fabrication facility in the electrical engineering department. The device is then fully tested, and after approval by the senior design faculty advisor, the de-vice is given to the client. Each of the student design teams receives feedback throughout the year from the client or client coordinator to ensure that the design meets its intended goal.

Each design team provides an oral presentation dur-ing regularly held seminars in the department. In the past, local TV stations have filmed the demonstration of the senior design projects, and broadcast the tape on their news show. This media exposure usually re-sults in viewers contacting the electrical engineering department with requests for projects to improve the life of another individual, further expanding the im-pact of the program.

Design facilities are provided in three separate labo-ratories for analysis, prototyping, testing, printed cir-cuit board layout, fabrication, and redes-ign/development. The first laboratory is a room for team meetings during the initial stages of the design. Data books and other resources are available in this room.

There are also twelve workstations available for teams to test their design, and verify that the design parameters have been meet. These workstations con-sist of a power supply, waveform generator, oscillo-scope, breadboard, and a collection of hand tools.

The second laboratory contains Intel computers for analysis, desktop publishing and microprocessor testing. The computers all have analysis, CAD and desktop publishing capabilities so that students may easily bring their design projects from the idea to im-plementation stage. Analysis software supported in-cludes Microsoft EXCEL and Lotus 123 spreadsheets,


PSpice, MATLAB, MATHCAD, and VisSim. Desktop publishing supported includes Microsoft Word for Windows, Aldus PageMaker, and technical illustra-tion software via AutoCAD and OrCAD. A scanner with image enhancement software and a high-resolution printer are also available in the laboratory.

The third laboratory is used by the teams for fabri-cation. Six workstations exist for breadboard testing, soldering, and finish work involving printed circuit boards. Sufficient countertop space exists so that teams may leave their projects in a secure location for ease in work.

The electrical engineering department maintains a relatively complete inventory of electronic compo-nents necessary for design projects, and when not in stock, has the ability to order parts with minimal de-lay. The department also has a teaching assistant as-signed to this course on a year round basis, and an electronics technician available for help in the analy-sis and construction of the design project.

There were many projects constructed at NDSU (and probably at many other universities) that proved to be unsafe or otherwise unusable for the intended indi-vidual, despite the best efforts of the student teams under the supervision of the faculty advisors. These projects are undocumented.

University of Connecticut Design Experiences In August 1998 the Department of Electrical & Sys-tems Engineering (ESE) at UConn, in collaboration with the School of Hearing and Speech Sciences at Ohio University, received a five-year NSF grant for senior design experiences to aid persons with dis-abilities. This NSF project was a pronounced change from previous design experiences at UConn that in-volved industry sponsored projects carried out by a team of student engineers.

In order to provide effective communication between the sponsor and the student team, a WWW based ap-proach was implemented.3 Under the new scenario,

3 Enderle, J.D., Browne, A.F., and Hallowell, B. (1998). A WEB Based Approach in Biomedical Engineering Design Education. Biomedical Sciences Instrumenta-tion, 34, pp. 281-286.

students worked individually on a project and were divided into teams for weekly meetings. The purpose of the team was to provide student derived technical support at weekly meetings. Teams also formed throughout the semester based on need to solve tech-nical problems. After the problem was solved the team dissolved and new teams were formed.

Each year, 25 projects are carried out by the students at UConn. Five of the 25 projects are completed through collaboration with personnel at Ohio Uni-versity using varied means of communication cur-rently seen in industry, including video conferencing, the WWW, telephone, e-mail, postal mailings, and videotapes.

ESE senior design consists of two required courses, Electrical Engineering (EE) Design I and II. EE Design I is a two-credit hour course in which students are in-troduced to a variety of subjects. These include: work-ing on teams, design process, planning and schedul-ing (time-lines), technical report writing, proposal writing, oral presentations, ethics in design, safety, li-ability, impact of economic constraints, environ-mental considerations, manufacturing and market-ing. Each student in EE Design I:

• Selects a project to aid a disabled individual after interviewing a person with disabilities;

• Drafts specifications;

• Prepares a project proposal;

• Selects an optimal solution and carries out a feasibility study;

• Specifies components, conducts a cost analy-sis and creates a time-line; and

• Creates a paper design with extensive model-ing and computer analysis.

EE Design II is a three-credit hour course following Design I. This course requires students to implement a design by completing a working model of the final product. Prototype testing of the paper design typi-cally requires modification to meet specifications.


These modifications undergo proof of design using commercial software programs commonly used in in-dustry. Each student in EE Design II:

• Constructs and tests a prototype using modu-lar components as appropriate;

• Conducts system integration and testing;

• Assembles final product and field-tests the device;

• Writes final project report;

• Presents an oral report using PowerPoint on Senior Design Day; and

• Gives the device to the client after a waiver is signed.

Course descriptions, student project homepages and additional resources are located at http://www.ee.uconn.edu/~design/.

The first phase of the on-campus projects involves creating a database of persons with disabilities and then linking the student with a person with a disabil-ity. The A.J. Pappanikou Center provided a database with almost 60 contacts and a short description of the disabilities in MS Access. The involvement of the Center was essential for the success of the program. The A.J. Pappanikou Center is Connecticut’s Univer-sity Affiliated Program (UAP) for disabilities studies. As such, relationships have been established with the Connecticut community of persons affected by dis-abilities, including families, caregivers, advocacy and support groups and, of course, persons with disabili-ties themselves. The Center serves as the link between the person in need of the device and the ESE Design course staff. The Center has established ongoing rela-tionships with Connecticut’s Regional Educational Service Centers, the Birth to Three Network, the Con-necticut Tech Act Project, and the Department of Men-tal Retardation. Through these contacts, the Center facilitates the interaction between the ESE students, the client coordinators (professionals providing sup-port services, such as the speech-language patholo-gists, physical and occupational therapists), the indi-viduals with disabilities (clients), and clients’ fami-lies.

The next phase of the course involves students’ selec-tion of projects. Using the on-campus database, each student selects two clients to interview. The student and a UConn staff member meet with the client and/or client coordinator to identify a project that would improve the quality of life for the client. After the interview, the student writes a brief description for each project. Almost all of the clients interviewed have multiple projects. Project descriptions include: contact information (client, client coordinator, and student name) and a short paragraph describing the problem. These reports are collected, sorted by topic area, and put into a Project Notebook. In the future, these projects will be stored in a database accessible from the course server for ease in communication.

Each student then selects a project from a client that he/she has visited, or from the Project Notebook. If the project selected was from the Project Notebook, the student visits the client to further refine the project. Because some projects do not involve a full academic year to complete, some students work on multiple projects. Students submit a project statement that de-scribes the problem, including a statement of need, basic preliminary requirements, basic limitations, other data accumulated, and important unresolved questions.

Specific projects at Ohio University are established via distance communication with the co-principal in-vestigator, who consults with a wide array of service providers and potential clients in the Athens, Ohio region.

The stages of specification, project proposal, paper design and analysis, construction and evaluation, and documentation are carried out as described ear-lier in the overview of engineering design.

To facilitate working with sponsors, a WWW based approach is used for reporting the progress on pro-jects. Students are responsible for creating their own WWW sites that support both html and pdf formats with the following elements:

• Introduction for layperson

• Resume

• Weekly reports


• Project statement

• Specifications

• Proposal

• Final Report

Weekly Schedule Weekly activities in EE Design I consist of lectures, student presentations and a team meeting with the instructor. Technical and non-technical issues that impact the design project are discussed during team meetings. Students also meet with cli-ents/coordinators at scheduled times to report on progress.

Each student is expected to provide an oral progress report on his or her activity at the weekly team meet-ing with the instructor, and record weekly progress in a bound notebook and on the WWW site. Weekly re-port structure for the WWW includes: project identity, work completed during the past week, current work within the last day, future work, status review and at least one graphic. The client and/or client coordina-tor uses the WWW reports to keep up with project so that they can provide input on the progress. Weekly activities in EE Design II include team meetings with the course instructor, oral and written progress re-

ports, and construction of the project. As before, the WEB is used to report project progress and communi-cate with the sponsors.

For the past two years, the student projects have been presented at the annual Northeast Biomedical Engi-neering Conference.

Other Engineering Design Experiences Experiences at other universities participating in this NSF program combine many of the design program elements that are presented for Texas A&M Uni-versity and North Dakota State University. Still, each university’s program is unique. In addition to the de-sign process elements already described, the State University of New York at Buffalo under the direction of Dr. Joseph Mollendorf, requires that each student go through the preliminary stages of a patent applica-tion. Naturally, projects worthy of a patent applica-tion are actually submitted. Thus far, a patent was is-sued for a "Four-Limb Exercising Attachment for Wheelchairs" and another patent has been allowed for a "Cervical Orthosis."

13

CHAPTER 2 EDUCATIONAL OUTCOMES

ASSESSMENT:IMPROVING DESIGN PROJECTS TO AID PERSONS WITH

DISABILITIES Brooke Hallowell

Of particular interest to persons interested in the en-gineering education are the increasingly outcomes fo-cused standards of the Accrediting Board for Engi-neering and Technology (ABET).4 This chapter is of-fered as an introduction to the ways in which im-proved foci on educational outcomes may lead to: (a) improvements in the learning of engineering stu-dents, especially those engaged in design projects to aid persons with disabilities, and consequently, (b) improved knowledge, design and technology to bene-fit individuals in need.

Brief History As part of a movement for greater accountability in higher education, US colleges and universities are experiencing an intensified focus on the assessment of students’ educational outcomes. The impetus for outcomes assessment has come most recently from accrediting agencies. All regional accrediting agen-cies receive their authority by approval from the Council for Higher Education Accreditation (CHEA), which assumed this function from the Council on Recognition of Postsecondary Accreditation (CORPA) in 1996. The inclusion of outcomes assessment stan-dards as part of accreditation by any of these bodies,

4 Accrediting Board for Engineering and Technology (2000). Criteria for Accrediting Engineering Programs. ABET: Baltimore, MD.

such as North Central, Middle States, or Southern As-sociations of Colleges and Schools, and professional accrediting bodies, including ABET, is mandated by CHEA, and thus is a requirement for all regional as well as professional accreditation. Consequently, candidates for accreditation are required to demon-strate plans for assessing educational outcomes, and evidence that assessment results have led to im-proved of teaching and learning and, ultimately, bet-ter preparation for entering the professions. Accredit-ing bodies have thus revised criteria standards for ac-creditation with greater focus on the “output” that students can demonstrate and less on the “input” they are said to receive.5

“Meaningful” Assessment Practices Because much of the demand for outcomes assess-ment effort is perceived, at the level of instructors, as a bureaucratic chore thrust upon them by administra-tors and requiring detailed and time-consuming documentation, there is a tendency for many faculty

5 Hallowell, B. & Lund, N. (1998). Fostering program improvements through a focus on educational out-comes. In Council of Graduate Programs in Commu-nication Sciences and Disorders, Proceedings of the nineteenth annual conference on graduate education, 32-56.


members to avoid exploration of effective assessment practices. Likewise, many directors of academic de-partments engage in outcomes assessment primarily so that they may submit assessment documentation to meet bureaucratic requirements. Thus, there is a ten-dency in many academic units to engage in assess-ment practices that are not truly “meaningful”.

Although what constitutes an “ideal” outcomes as-sessment program is largely dependent on the par-ticular program and institution in which that pro-gram is to be implemented, there are at least some generalities we might make about what constitutes a “meaningful” program. For example:

An outcomes assessment program perceived by faculty and administrators as an imposition of bu-reaucratic control over what they do, remote from any practical implications… would not be consid-ered “meaningful.” Meaningful programs, rather, are designed to enhance our educational missions in specific, practical, measurable ways, with the goals of improving the effectiveness of training and education in our disciplines. They also in-volve all of a program’s faculty and students, not just administrators or designated report writers. Furthermore, the results of meaningful assessment programs are actually used to foster real modifica-tions in a training program.6

Outcomes Associated with Engineering Design Projects Despite the NSF’s solid commitment to engineering design project experiences, and widespread enthusi-asm about this experiential approach to learning and service, there is a lack of documented solid empirical support for the efficacy and validity of design project experiences and the specific aspects of implementing those experiences. Concerted efforts to improve learn-ing, assessment methods and data collection concern-ing pedagogic efficacy of engineering design project experiences will enhance student learning while benefiting the community of persons with disabilities.

6 Hallowell, B. (1996). Innovative Models of Curricu-lum/Instruction: Measuring Educational Outcomes. In Council of Graduate Programs in Communication Sciences and Disorders, Proceedings of the Seven-teenth Annual Conference on Graduate Education, 37-44.

Agreeing on Terms There is great variability in the terminology used to discuss educational outcomes. How we develop and use assessments matters much more than our agree-ment on the definitions of each of the terms we might use to talk about assessment issues. Still, for the sake of establishing common ground, a few key terms are highlighted here.

Formative and Summative Outcomes Formative outcomes indices are those that can be used to shape the experiences and learning opportu-nities of the very students who are being assessed. Some examples are surveys of faculty regarding cur-rent students’ design involvement, on-site supervi-sors’ evaluations, computer programming proficiency evaluations, and classroom assessment techniques.7 The results of such assessments may be used to char-acterize program or instructor strengths and weak-nesses, as well as to foster changes in the experiences of those very students who have been assessed. Summative outcomes measures are those used to characterize programs (or college divisions, or even whole institutions) by using assessments intended to capture information about the final products of our programs. Examples are student exit surveys, sur-veys of graduates inquiring about salaries, employ-ment, and job satisfaction, and surveys of employers of our graduates.

The reason the distinction between these two types of assessment is important is that, although formative assessments tend to be the ones that most interest our faculty and students and the ones that drive their daily academic experiences, the outcomes indices on which most administrators focus to monitor institu-tional quality are those involving summative out-comes. It is important that each of academic unit strive for an appropriate mix of both formative and summative assessments.

Cognitive/Affective/Performative Outcome Distinc-tions To stimulate our clear articulation of the specific out-comes targeted within any program, it is helpful to have a way to characterize different types of out-

7 Angelo, T. A., & Cross, K. P. (1993). Classroom as-sessment techniques: A handbook for college teach-ers. San Francisco: Jossey-Bass.

Chapter 2: Educational Outcomes Assessment: Improving Design Projects To Aid Persons With Disabilities 15

comes. Although the exact terms vary from context to context, targeted educational outcomes are commonly characterized as belonging to one of three domains: cognitive, affective, and performative. Cognitive out-comes are those relating to intellectual mastery, or mastery of knowledge in specific topic areas. Most of our course-specific objectives relating to a specific knowledge base fall into this category. Performance outcomes are those relating to a student’s or gradu-ate’s accomplishment of a behavioral task. Affective outcomes relate to personal qualities and values that students ideally gain from their experiences during a particular educational and training program. Exam-ples are appreciation of various racial, ethnic, or lin-guistic backgrounds of individuals, awareness of bi-asing factors in the design process, and sensitivity to ethical issues and potential conflicts of interest in professional engineering contexts.

The distinction among these three domains of tar-geted educational outcomes is helpful in highlighting areas of learning that we often proclaim to be impor-tant but that we do not assess very well. Generally, we are better at assessing our targeted outcomes in the cognitive area, for example, with in-class tests and papers, than we are with assessing the affective areas of multicultural sensitivity, appreciation for collabo-rative teamwork, and ethics. Often, our assessment of performative outcomes is focused primarily on stu-dents’ design experiences, even though our academic programs often have articulated learning goals in the performative domain that might not apply only to de-sign projects.

Faculty Motivation A critical step in developing a meaningful educa-tional outcomes program is to address directly perva-sive issues of faculty motivation. Faculty resistance is probably due in large part to the perception that out-comes assessment involves the use of educational and psychometric jargon to describe program indices that are not relevant to the everyday activities of fac-ulty members and students. By including faculty, and perhaps student representatives, in discussions of what characterizes a meaningful assessment scheme to match the missions and needs of individ-ual programs, and by agreeing to develop outcomes assessment practices from the bottom up, rather than in response to top-down demands from administra-tors and accrediting agencies, current skeptics on our faculties are more likely to engage in assessment ef-

forts. Additional factors that might give faculty the incentive to get involved in enriching assessment practices include:

Consideration of outcomes assessment work as part of annual merit reviews; provision of materi-als, such as sample instruments; or resources, such as internet sites; to simplify the assessment instrument design process; demonstrate means by which certain assessments, such as student exit or employer surveys, may be used to [a] pro-gram’s advantage in negotiations with … ad-ministration (for example, to help justify funds for new equipment, facilities, or salaries for faculty and supervisory positions); and notice and re-ward curricular modifications and explorations of innovative teaching methods initiated by the faculty in response to program assessments.5

With the recent enhanced focus of on educational out-comes in accreditation standards of ABET, and with all regional accrediting agencies in the Unites States now requiring extensive outcomes assessment plans for all academic units, it is increasingly important that we share assessment ideas and methods among academic programs. It is also important that we ensure that our assessment efforts are truly mean-ingful, relevant and useful to our students and fac-ulty.

The next chapter serves as an invitation to readers of this book to join in collaborative efforts to improve de-sign experiences, student learning, and design prod-ucts through improved assessment practices. Future annual publications on the NSF-sponsored engineer-ing design projects to aid persons with disabilities will include input from students, faculty, supervisors, and consumers on ways to enhance associated edu-cational outcomes in specific ways. The editors of this book look forward to input from the engineering education community for dissemination of further in-formation to that end.

17

CHAPTER 3 AN INVITATION TO COLLABORATE IN

USING ASSESSMENT TO IMPROVE DESIGN PROJECTS

Brooke Hallowell

In Chapter 2, we discussed educational outcomes as-sessment, emphasizing ways in which clearer foci on educational outcomes may lead to improvements in the learning of engineering students, and, conse-quently, improved knowledge, design and technology to benefit individuals in need. We described con-certed efforts among accrediting agencies, including the Accrediting Board for Engineering and Technol-ogy (ABET), to improve the accountability of educa-tional institutions through improved assessment practices. We discussed how a “meaningful” empha-sis on educational outcomes helps overcome bureau-cratic hurdles in academe, and enhances our educa-tional missions in specific, practical, measurable ways by improving the effectiveness of training and education. This chapter serves as an invitation to readers to join in collaborative efforts to enrich mean-ingful educational outcomes assessment efforts asso-ciated with NSF-sponsored design projects to aid per-sons with disabilities.

A look at ABET’s requirements for the engineering design experiences in particular8 may give us further direction in areas that are essential to assess in order to monitor the value of engineering design project ex-periences. For example, the following are considered “fundamental elements” of the design process: “the


establishment of objectives and criteria, synthesis, analysis, construction, testing, and evaluation” (p. 11). Furthermore, according to ABET, specific tar-geted outcomes associated with engineering design projects should include: development of student crea-tivity, use of open-ended problems, development and use of modern design theory and methodology, for-mulation of design problem statements and specifica-tions, consideration of alternative solutions, feasibil-ity considerations, production processes, concurrent engineering design, and detailed system descriptions. The accrediting board additionally stipulates that it is essential to include a variety of realistic constraints, such as economic factors, safety, reliability, aesthetics, ethics, and social impact. ABET’s most recent, re-vised list of similar targeted educational outcomes is presented in the Appendix. We encourage educators, students and consumers to consider the following questions:

• Are there outcomes, in addition to those specified by ABET, that we target in our roles as facilitators of design projects?

• Do the design projects of each of the students in NSF-sponsored programs incorporate all of these features? How may we best charac-terize evidence that students engaged in Pro-jects to Aid Persons with Disabilities effec-tively attain desired outcomes?


• Are there ways in which students’ perform-ance within any of these areas might be more validly assessed?

• How might improved formative assessment of students throughout the design experience be used to improve their learning in each of these areas?

Readers interested in addressing such questions are encouraged to send comments to the editors of this book. We are particularly interested in disseminat-ing, through future publications, specific assessment instruments that readers find effective in evaluating targeted educational outcomes in NSF-sponsored en-gineering design projects. Basic terminology related to pertinent assessment issues is presented in Chap-ter 2. Cognitive, performative, and affective types of outcomes are reviewed briefly here, along with lists of the types of assessments that might be shared among those involved in engineering design projects.

Cognitive outcomes are those relating to intellectual mastery, or mastery of knowledge in specific topic ar-eas. Some examples of these measures are:

• Comprehensive exams

• Items embedded in course exams

• Pre-post tests to assess “value added”

• Design portfolios

• Student self evaluation of learning during a design experience

• Alumni surveys

• Employer surveys

Performative outcomes are those relating to a student’s or graduate’s accomplishment of a behavioral task. Some performance measures include:

• Evaluation of graduates’ overall de-sign experience

• Mastery of design procedures or skills expected for all graduates

• Student evaluation of final designs, or of design components

• Surveys of faculty regarding student design competence

• Evaluation of writing samples

• Evaluation of presentations

• Evaluation of collaborative learning and team-based approaches

• Evaluation of problem-based learn-ing

• Employer surveys

• Peer evaluation; e.g., of leadership or group participation

Affective outcomes relate to personal qualities and values that students ideally gain from their educa-tional experiences. These may include:

• Student journal reviews

• Supervisors’ evaluation of students’ interactions with persons with dis-abilities

• Evaluations of culturally-sensitive reports

• Surveys of attitudes or satisfaction with design experiences

• Interviews with students

• Peers’, supervisors’, employers’ evaluations

We welcome contributions of relevant formative and summative assessment instruments, reports on as-sessment results, and descriptions of assessment pro-grams and pedagogical innovations that appear to be effective in enhancing design projects to aid persons with disabilities.

Please send queries or submissions for consideration to: Brooke Hallowell, Ph.D. School of Hearing and Speech Sciences Lindley Hall 208 Ohio University Athens, OH 45701 E-mail: [email protected]

Chapter 3: An Invitation To Collaborate In Using Assessment To Improve Design Projects 19

APPENDIX: Desired educational outcomes as articulated in ABET’s new “Engineering Criteria 2000” (Criterion 3, Program Outcomes and Assessment)

Engineering programs must demonstrate that their graduates have:

(a) an ability to apply knowledge of mathematics, science, and engineering

(b) an ability to design and conduct experiments, as well as to analyze and interpret data

(c) an ability to design a system, component, or process to meet desired needs

(d) an ability to function on multi-disciplinary teams

(e) an ability to identify, formulate, and solve engineering problems

(f) an understanding of professional and ethical responsibility

(g) an ability to communicate effectively

(h) the broad education necessary to understand the impact of engineering solutions in a global and societal context

(i) a recognition of the need for, and an ability to engage in life-long learning

(j) a knowledge of contemporary issues

(k) an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice (p. 38-39).


21

CHAPTER 4 ARIZONA STATE UNIVERSITY

College of Engineering and Applied Sciences Bioengineering Program

Department of Chemical, Bio & Materials Engineering Tempe, Arizona 85287-6006

Principal Investigators:

Gary T. Yamaguchi, Ph.D. (602) 965-2268 [email protected]

Jiping He, Ph.D. (602) 965-0092


VOLUNTARY-OPENING TRANSRADIAL PROSTHESIS FOR USE WITH WEIGHT TRAINING

EQUIPMENT Designer: Jill M. Vandenburg

Client: Kristin Varon Graduate Student: Chad Kennedy

Clinician: James M. Duston, Prosthetic Orthotic Associates, Scottsdale, AZ Supervising Professor: Gary T. Yamaguchi, Ph.D.

Bioengineering Program Department of Chemical, Bio & Materials Engineering

Arizona State University Tempe, AZ 85287-6006

INTRODUCTION An upper extremity weight training prosthesis was designed for a client who was born without her right wrist, hand, and the majority of her forearm. The prosthesis enables the client to grasp the weight lift-ing bar at the beginning of the exercise, and to release it at the end of the exercise, without any help from the left hand. The device is a voluntary-opening prosthe-

sis that provides the client with a standard cable in-terface with which she is familiar.

SUMMARY OF IMPACT A college student born without her right wrist, hand, and the majority of her forearm, required a prosthetic device to enable her to utilize weight training equip-ment. Her goal was to exercise the muscles of her

Figure 4.1. Photograph of the Transradial Prosthesis for Use with Weight Training Equipment.

Chapter 4: Arizona State University 23

right upper arm, shoulder, and back.

The prosthesis was designed to be used with pulling devices, including lateral pull-down and rowing ma-chines. It could potentially be used for pushing exer-cises, including bench and incline press and various dumbbell exercises, by designing additional custom terminal devices.

TECHNICAL DESCRIPTION This design incorporates a gated hook. A heavy-duty cable runs from the gate on the terminal device, or hand portion of the prosthesis, to a loose strap on an upper body harness. The gate of the terminal device opens when a maximum amount of tension is exerted on the cable. This occurs when the client performs various upper body motions, including biscapular abduction or humeral flexion. As the client relaxes her arm, the tension in the cable decreases and the gate closes. As she reaches out for the weight lifting bar, the terminal device opens, allowing her to clamp onto the bar. As she performs the weight lifting mo-tion, the lever arm remains closed, keeping the bar from slipping out of the terminal device. When she extends her arm back to her original starting position, the tension in the cable increases and the lever arm opens, allowing her to release the prosthesis from the bar. This also allows her to quickly release the bar in the event of a problem.

The primary design specifications included: (1) the client can manually affix the prosthesis to the resid-ual limb with only one hand; (2) the correct muscle groups are exercised during the weight lifting motion; (3) the device can withstand high normal and shear stresses under a wide range of loads; (4) the prosthe-sis mass must match, as closely as possible, the mass of the client’s left forearm, wrist, and hand; (5) the length of the prosthesis should equal the length from the end of the client’s residual limb to the metacarpo-phalangeal joints on a closed hand; (6) the device should maximize the range of motion of the client’s elbow joint; and (7) it should be easy to maintain and repair.

The prosthesis is comprised of six different parts: the terminal device (hand), wrist unit, forearm unit, el-bow socket, harness, and cable system. The design and function of the terminal device is similar to that of a mountain climbing carabiner, consisting of a “C” shaped outer bar and a spring-loaded manually opening “gate” which closes the opening of the C

(Figures 4.3, 4.4, and 4,5). The outer C and gate of the terminal device are composed of aluminum alloy 7175-T66 while the lever arm and cable pins are made of stainless steel. The bottom of the terminal device has a ½” aluminum stud, which is used to attach the terminal device to the wrist unit. The C and stud were machined out of a single block of aluminum for strength. To enhance the wear resistance of the de-vice, the aluminum components were anodized after fabrication and a rubber lining was added to the in-ternal and external contact areas.

The wrist unit is a standard aluminum upper extrem-ity prosthetic component from Hosmer-Dorrance. It connects the terminal device and the forearm unit and allows the user to position the terminal device prior to use. There is constant friction between the wrist unit and the terminal device during exercise.

Figure 4.2. Close-up of the Transradial Prosthesis for Use with Weight Training Equipment.


The forearm unit and elbow socket were custom made to fit the client’s residual limb. The forearm unit was made of a lamination, comprised of two layers of car-bon braid sock, two layers of Kevlar, and seven layers of ny-glass lay-up. The elbow socket is comprised of two separate parts: the silicone socket and the hard socket. The silicone socket is made of a silicone-platinum gel that is covered with an external, nylon liner. It is a standard component from Ossur, a com-pany in Iceland. An impression of the client’s resid-ual limb and elbow was made using a casting mate-rial, and the hard portion of the socket was created from this impression. The resulting socket shell is composed of serlin and is covered with Pedalin foam and the forearm unit lamination.

The harness is a standard upper extremity prosthetic component ordered from Hosmer-Dorrance. The har-ness is a configuration of Dacron straps, which wrap around the user’s upper body and attach to the re-mainder of the prosthesis via a cable and cable hous-ing. It serves two purposes: it helps to secure the re-mainder of the prosthesis onto the residual limb and upper arm, and it provides a mechanism for volun-tary operation of the terminal device via upper body motion.

The cable system is used to provide voluntary control of the terminal device. A steel cable is attached from the terminal device to a loose strap on the harness, the control attachment strap. Between the terminal de-vice and the harness, the cable passes through two

aluminum housing units attached to the forearm unit. The cable housing units maintain the cable at a con-stant length throughout the range of motion of the el-bow joint, help to secure the cable system to the pros-thesis, and also align the cable toward its attachment location on the terminal device.

The device has been tested using the weight training equipment. It functions effectively for exercises that involve pulling (from an arm extended position to a flexed position). The client also uses the prosthesis to perform several other exercises not initially planned. These include push-ups, one-arm dumbbell rows, and shoulder shrugs. By wrapping a set of ankle or wrist weights around the terminal device, she may also perform both front and lateral shoulder raises. However, unless further adaptations are made, the device does not work as well in these other exercise modalities.

The client has used the device for lateral pull-downs and rowing, three times per week for six months. She suggests that the inner liner be made of a stiffer plas-tic for greater durability.

The final cost of the terminal device was approxi-mately $1490. The socket and forearm orthosis was made with the assistance of Prosthetic Orthotic Asso-ciates of Scottsdale, AZ.


ITEM DESCRIPTION SHEET1 BASE 2 & 32 LEVER ARM 43 CABLE PIN 54 LEVER ARM PIN 55 SPRING 66 SPRING 67 SET SCREW NOTE 18 SET SCREW NOTE 1

NOTES:1. MAT'L: ITEM 1 & ITEM 2: ALUMINUM ALLOY, 7175-T66 ITEM 3 & ITEM 4: STAINLESS STEEL ITEM 5: STD. STOCK SPRING ITEM 7: STD. SET SCREW, 2-56 X 2.54 LONG ITEM 8: STD. SET SCREW, 1/4-20 X 3.18 LONG2. FINISH ITEM 1 & ITEM 2: HARD ANODIZE, BLACK, PER MIL-A-8625F3. DEBURR ALL SHARP EDGES AFTER MACHINING.4. ALL HOLES ARE TO BE MASKED OR PLUGGED PRIOR TO ANODIZE.

ITEM 1

ITEM 2

ITEM 3

ITEM 4

ITEM 5

ITEM 6

ITEM 7

ITEM 8

Figure 4.3. Assembly Drawing of Terminal Device.


80.00

40.00

15.00

1/2-20 UNF-2A

125.00

2.0

18.0

24.00

8.00

4.00

13.00

30.00

62.50

60.00 10.00 TYP.

R

SEE VIEW BSHEET 3

SEE VIEW CSHEET 3

SEE VIEW ASHEET 3

30.00

2X 10.00

2X 10.00

10.00 7.67

2X 34 DEG.

Figure 4.4. Dimensions of the Terminal “C” Device.


70.00

21.07

15.00

2X 7.00

2X 2.25

2X 2.25

A A

10.002.38 DIA.

8.50

2X 4.50

2X 4.50

2X 4.50

20.00

4X 2-56 UNC-2B X 5.50 DEEP

10.00

5.00

10.00

2X 7.00 2X 4.50

4X 5.00

2X SLIDE FIT FOR 3.96 DIA PIN

R3.18 TYP

R3.57

SECTION A-A

Figure 4.5. Dimensions of the Manually Operated “Gate” of the Terminal Device.


SHOWER CHAIR FOR A CLIENT WITH DE SANTIS CACHIONE

Designer: Kevin Cordes Client: Angel Bueno

Supervising Professor: Gary T. Yamaguchi, Ph.D. Bioengineering Program

Department of Chemical, Bio & Materials Engineering Arizona State University Tempe, AZ 85287-6006

INTRODUCTION This project’s objective was to create a shower chair which would ease bathing and transfers to and from the shower for a client with an extremely rare condi-tion, de santis cachione. This condition has been diag-nosed approximately 20 times since its discovery in 1932. It has many of the common traits of cerebral palsy, except that de santis cachione causes a progres-sive deterioration in condition.

The client once had nearly full function in all modali-ties, but his condition has steadily progressed so that, at his current age of 26, he has lost his ability to am-bulate, speak, and see. He still responds to light and darkness, and to auditory stimuli. The disease is now affecting his hearing, and has caused a skin disorder known as xenoderma pigmentosa, which causes skin damage after exposure to direct sunlight. Due to the severity of the client’s condition, he is supervised con-tinuously.

SUMMARY OF IMPACT Before the design of this project, the client’s mother carried him from his wheelchair in the living room to a plastic patio chair used in the shower. During the shower, his muscles would relax, causing him to slide out of the chair, or lean to one side.

The shower chair was designed to hold the client up-right comfortably in the shower, at an optimal height for his mother to bathe him. It allows for easy and safe transfer and meets bathroom size constraints.

TECHNICAL DESCRIPTION The technical specifications of the shower chair were derived primarily from ergonomic factors. The cli-

ent’s weight and body dimensions determined the seat area of the chair, while the transfer and bathroom space limitations were used to determine much of the chair base design (Figure 4.7). For safety reasons, the design was tested with individuals weighing about two and one-half times the client’s weight of 60 lbs. A

Figure 4.6. Angel in his Shower Chair with his Mother and Graduate Student Coordinator


four-wheel base configuration was chosen for ease of rolling and to prevent tipping. The 3-inch diameter caster wheels easily negotiate the rugs, sill, and threshold of the home and bathroom, and are rated at 150 psi, or nearly 10 times the expected loading. The frame is made from one-inch outer diameter T6061 aluminum tubing with a 1/8-inch wall thickness. All frame joints were welded, except for the pin connec-tions for the adjustment rod. To adjust the reclining angle, the person giving the user a shower uses the adjustable pin positions on the adjustment rod to ro-tate the chair from an upright sitting position to one reclined at 45°. An adjustable spring/damper device connected between the base and the rotating seat con-trols the rate of rotation. The device resists motion in both directions, and can be set to give variable resis-tance using a screw setting. An adjustable 2-inch ny-lon-webbing belt with a Delrin clasp is used to secure the user and is positioned across the chest, away from

his feeding tube and button. The seating material is made from a polyester mesh typically used for out-door furniture. It is mildew-resistant and porous enough to allow water to pass through it, while re-taining enough strength to support the client’s weight. The material was attached to the frame by stretching it around the tubing and securing it with aluminum POP rivets and washers.

Since the shower chair was to be used in a corrosive environment, all component pieces, fasteners, etc. were made of corrosion resistant materials. To im-prove the appearance of the chair, the aluminum frame was coated with bright blue Hammerite paint.

Though every effort was made to make the chair sta-ble and structurally sound, it is assumed that the user is under supervision at all times.

The overall material costs were estimated at $141.58.

Figure 4.7. Client and his Shower Chair in the Shower Enclosure.


A FLY CASTING ORTHOSIS FOR A PATIENT WITH QUADRIPLEGIA

Designer: Jason Lieb Client: Don Price, Fishing Has No Boundaries, AZ Chapter



INTRODUCTION A prototype fly-fishing orthosis was designed for use by a patient with mild quadriplegia. The device was designed to allow him to perform a proper casting stroke, control slack line, and reel - - all motions that are necessary for fly fishing. The person for whom the device was designed has no independent finger movement or grip strength, but he is able to move his arms well. Special devices were needed to attach the rod to the user’s hand, to catch the slack line coming from the first “stripper” line guide, to grip the line during the cast, and to release the line at the end of the casting stroke. Combinations of mountable sup-port devices, alternative reels, and wrist brace at-tachments were considered before a final design con-cept was selected. The final prototype consists of two polypropylene orthoses fitted to the user’s hands and arms. The left hand orthosis is strapped onto the forearm and hand and has a hole to allow turning of the reel handle and a “finger” to allow hooking, grasping, and releasing of slack line. The right arm orthotic is strapped to the forearm and hand and tightly grips a standard cork fly rod handle.

SUMMARY OF IMPACT The client is presently one of the cofounders of the Arizona Chapter of “Fishing Has No Boundaries”, an organization dedicated to introducing persons with disabilities to fishing and enabling them to partici-pate in the sport. While electric reels and reeling de-vices, spring loaded casting devices, specialized tires for “off-road wheelchairing” have been developed to enable people with quadriplegia to fish with conven-tional fishing tackle, no known devices enable such persons to fish with a fly rod and fly line. Instead of performing only a long forward casting stroke with a

heavy weight and light line, as in conventional fish-ing, fly fishing requires one to perform both a back-ward stroke (the backcast) and a forward stroke. Be-cause good fly casting only requires a short backward and short forward stroke that are timed appropri-ately, it was felt that people with quadriplegia could participate in fly fishing. People with mild quadri-plegia typically have enough upper body mobility and voluntary arm movement to support the move-ments involved in fly fishing. The most difficult thing to teach a non-disabled individual is not to flex the

Figure 4.8. Client Testing the Fly-Casting Orthosis.


wrists backward during the backcast. With an ortho-sis that prevents backward wrist flexion, people with quadriplegia would not have to unlearn this highly unproductive movement. With further development and appropriate modifications, this prototype might be made as a commercial device that could be made available to other people with quadriplegia.

TECHNICAL DESCRIPTION The final design of the fly-fishing device consists of a right and left orthotic (Figure 4.9) and a slightly modi-fied reel handle. The left hand orthotic straps onto the hand and wrist and has two attachment func-tions: 1) to grasp and pull in slack line, 2) to grasp the handle and turn the reel when fighting fish or reeling in slack line. The grasping and pulling func-tions are accomplished with a forked extension, shown in Figure 4.9. The reeling is accomplished by way of a milled slot and 7/16” hole built into the palm area which mates with the reel handle. The slot enables the user to find the reel handle easily so that once the reel handle is located within the hole the spool can be turned. The plastic reel handle was ex-tended slightly for more accessible use. The opposing orthosis straps onto the palm of the right (casting) hand. This device cradles the rod in a thermal cork lined inset, shown in Figure 4.9. The polypropylene material flexes and the cork lining compresses to ac-commodate the many rod handles available on the market. 1-inch nylon webbing straps with Velcro clo-sures and steel rings were attached to secure the or-thosis to the rod and to further secure the connection between the orthosis and the hand. The interiors of both orthotics are lined with Alliplast, a soft foam-like material, for comfort. Prototypes of the design were

made at the Prosthetic Orthotic Associates facilities in Scottsdale, Arizona. Casts were made of the right and left arms, with plaster bandages cut away, stapled back together, and used to form plaster molds of the arms. The dried and shaped molds were used to shape the preheated Alliplast liners and polypropyl-ene sheets. The polypropylene was then sealed and vacuumed to pull the plastic tight around the mold. Once cooled, the shapes were further refined and smoothed to the desired shape. Thermal cork was heated and glued to the right orthotic and then shaped to grip the handle of a standard fly rod. Dur-ing operation, the user pulls the slack out of the line by hooking the line or sliding the fork prongs around the line, slightly twisting, and pulling down. When enough slack is pulled out, the user holds the line by pressing the fork with the line down into his lap. Slack is released when necessary. As with non-disabled individuals, learning these movements re-quires practice before actual use on the stream. Al-though designed to fit most individuals, each indi-vidual's mobility and skills determines how effective the device is for fly-fishing. It was found that the cli-ent did not actually need the left hand orthosis, as he was able to loosely hold the line with his left hand, an essential component to successful fly casting. Al-though the concept was effective, the right hand or-thosis was found to be a bit bulky and a new design is being considered. Also, it was determined that be-cause of the client’s weakness, a specially designed fly rod that is shorter and lighter in weight would make it easier for him to accelerate and decelerate. Total costs for the prototype device were estimated at $120.

Figure 4.9. The Left Hand Orthosis (Bottom) Reel Handle, Attached to a Standard Fly Rod Using a Friction Fitting, Two D Rings, and Velcro Straps.


AN EXERCISE/RANGE-OF-MOTION BIKE FOR A PATIENT WITH PARAPLEGIA

Designer: Tariq Al-lawati Client: Mike Davis, ASU



INTRODUCTION An exercise/range-of-motion (Ex/ROM) bike was de-signed for a person with paraplegia. The client re-quested a hand-driven device that would move his legs repeatedly through a wide range of motion. He had found that ranging his joints was useful because it reduces contractures and spasticity. The major de-sign components included a hand-controlled drive sprocket, a gear driven leg follower sprocket, a sliding seat, ankle and foot supports, and the overall frame.

SUMMARY OF IMPACT The aim of this design was to allow an efficient way for an adult with paraplegia to stretch and range his legs by cranking with his arms. The need for such a device is not limited to the individual for whom it was designed, but extends to other people with para-plegia, as well as to others requiring passive motion. Currently, similar devices are being used to rehabili-tate many individuals with various lower limb dis-abilities in the U.S. Most of these devices use electro-mechanical motors and gear arrangements to provide actuation.

This design promotes range-of-motion exercising of the lower limbs, which improves circulation, reduces muscle spasms and contractures, relieves joint stiff-ness, and promotes mental and physical health in pa-tients with spinal cord injury. This device also offers some upper body conditioning, since the upper body provides the work to range the lower body.

TECHNICAL DESCRIPTION The overall design is a synthesis of all major compo-nent designs (See Figure 4.10). The hand-controlling sprocket is positioned at approximately the user’s arm height. Foot pedals were used as handles in this design, but will be replaced with handgrips before de-livery to the user. Studies have shown that many people with lower limb disabilities prefer an average cadence of 15 rpms. The hand sprocket has a gear di-ameter ratio of 8:5 with respect to the leg sprocket. This allows the user to pedal more slowly, at a rate of about 9.4 rpms, to achieve the preferred cadence. It was easy to drive the legs through a cycle, even though the arms have a mechanical disadvantage via this gear ratio.

The leg pedals have plastic footpads and Velcro straps that hold the feet and provide proper foot posi-tioning. The ankle supports are made from a stiff but flexible plastic (similar to the plastic used in ski boots) and are strapped around the user’s shins. The ankle supports were found to be unnecessary for the client and were removed. The seat is made of me-dium-stiff foam, attached to plywood backing and covered with vinyl upholstery. The seat is bolted to steel bars that are welded to a slider collar. The collar slides along a 2” diameter tube with 4 possible pin settings spaced 2” apart. A ½” steel pin placed through the holes in the collar and mainframe tube al-lows 6” of travel at the 4 different pin settings.

The support frame is constructed of 1” square and 1” outer diameter mild steel tubes (all 1/8” wall), welded together and painted. Other final modifica-tions to be made to this device include: adding a


chain tension sprocket, adding a chain guard, install-ing a square tube and slider collar, and adding fur-ther frame support behind the device to maintain sta-bility during use.

Material costs for the Ex/ROM Bike were less than $250.00, as standard bicycle parts were used for most of the components.

Figure 4.10. Prototype for Exercise/Range-Of-Motion Bike.

35

CHAPTER 5 BINGHAMTON UNIVERSITY

Thomas J. Watson School of Engineering and Applied Science Department of Mechanical Engineering

P.O Box 6000 Binghamton, NY 13902-6000

Principal Investigator:

Richard S. Culver (607) 777-2880 [email protected]


COLLAPSIBLE ACTIVITY FRAME Designers: Jennifer Thurkins, Joel Andrews, Lucas Oracz, Owen Kim Client Coordinator: Donna Boisvert, Vestal School District (VSD)

Supervising Professor: Professor Richard S. Culver Department of Mechanical Engineering

Binghamton University, SUNY Binghamton, NY 13902-6007

INTRODUCTION A school district needed an activity frame, a device to hold visual stimuli for children of varying develop-mental stages. The device was required to stand above a child who is lying down or seated.

SUMMARY OF IMPACT The activity frame allows various toys to hang above or in front of a child. It enables a child to have toys within the child’s constant reach.

TECHNICAL DESCRIPTION The activity frame is constructed of 1 3/8” PVC furni-ture-grade plastic tubing. This material is both inex-pensive and durable. Telescoping tubes with push-button locks make it fully adjustable in height. The device is also foldable via pivoting joints on the end. To fold flat, the top portion is removed, leaving the two inner tubes free to pivot flat.

The final cost of the Activity Frame was approxi-mately $15.

Figure 5.1. Collapsible Activity Frame.

Chapter 5: Binghamton University 37

ADJUSTABLE HEIGHT COMPUTER MONITOR Designers: Aaron Ellis, Marin Jukic, Vinnie Rossi, Nathan Walker

Client Coordinator: Mary O’Dell, BOCES at Appalachian Supervising Professor: Professor Richard S. Culver

Department of Mechanical Engineering Binghamton University, SUNY Binghamton, NY 13902-6007

INTRODUCTION A desk was designed to incorporate a mechanism for holding a computer monitor closer to the students’ eyes, thereby increasing the visibility of computer graphics and text. The device accommodates a wheelchair, which has a higher-than-average desk-top.

SUMMARY OF IMPACT Many children with visual impairments are unable to use computers. A computer desk that brings the monitor closer to the user is desirable because visibil-ity of the monitor increases proportionally with de-creasing distance.

TECHNICAL DESCRIPTION The frame of the desk is made of pine. The table and walls are made of ½” luan plywood. The desk is high enough to accommodate a wheelchair, yet low enough to allow easy viewing of the monitor. There is storage space for the computer CPU to the left of the

user. The desk incorporates a commercial adjustable arm upon which the computer monitor is mounted. This allows users to bring the monitor closer to them. The arm is adjustable to accommodate many users.

Attached to the desk is an internal surge-protecting power supply. With the disconnection of one plug, the computer, monitor, and desk can be moved, on casters, as one piece. The final cost of the adjustable computer desk was approximately $125.

Figure 5.2. A computer and computer monitor stand for the visually impaired children.


BALANCE BEAM Designers: Alex Bell, Bryan Swanson, Erik Ng, Brian Pianoforte

Client Coordinator: Donna Boisvert, Vestal School District (VSD) Supervising Professor: Professor Richard S. Culver


INTRODUCTION A lightweight, portable balance beam was con-structed for use by the therapists in a school district. It is 2”x4” in cross section and 8’ long. It folds into four 2’ sections.

SUMMARY OF IMPACT A portable balance beam is used in several schools. It makes balance beam work more accessible to students and obviates the need to buy a balance beam for each school.

TECHNICAL DESCRIPTION The device is constructed of a wooden frame made of ¾”x1 ½” stock and covered with ¼” luan mahogany veneer. Eight feet long, it folds into four sections via

four hinges mounted within the balance beam. When extended, the beam is long enough for use, but when folded, it fits easily under the arm of the user. A lock-ing mechanism stabilizes the beam in both open and closed positions.

A carrying strap made of conventional backpack buckles and nylon allows for convenient carrying at one’s side.

The final cost of the Balance Beam was approximately $15.

Figure 5.3. Portable Balance Beam.


BED RAIL ASSIST Designers: Chris Jantzen, Steve Corletta, Vitaly Shusterov, Jeremy Rosen

Client Coordinator: Danny Cullen, STIC Supervising Professor: Professor Richard S. Culver


INTRODUCTION A device was designed to assist people who have trouble transferring themselves into and out of bed.

SUMMARY OF IMPACT Bed rails are an easy way to help a person get into and out of bed. However, most beds do not have bed rails. A device that mounts to any bed is useful for people who have trouble transferring themselves into and out of bed.

TECHNICAL DESCRIPTION The device is constructed primarily of 1 3/8” PVC pipe. The vertical post has a piece of steel conduit mounted inside for stiffening purposes. The base of the device is a circular piece of ¾” plywood, with a mounting flange for the PVC pipe.

The device is further supported by a 3/16” PVC panel that clamps to the vertical post and slides under the bed mattress. The panel is vertically adjustable to fit the height of the bed. The lifting handle is rotationally adjustable so that the bed rail assist can be used from virtually any direction.

PVC Slip Tee’s that fit the vertical PVC tube are used to allow for adjustment. The top Slip Tee has slots machined in its bottom edge that fit over the head of a cap screw. This allows the lifting handle to be set at several different positions.

The final cost of the Bed Rail Assist was approxi-mately $20.

Figure 5.4. Bed Rail Assist


CART WITH BASKET Designers: Michael Spector, Chris Lent, Jason Lewen, Xu An Zeng

Client Coordinator: Terry Terrell, STIC Supervising Professor: Professor Richard S. Culver


INTRODUCTION A cart with casters and a removable wire-frame bas-ket was built for a woman who has limited mobility and difficulty carrying hot items from the stove to other locations in the kitchen.

SUMMARY OF IMPACT Conventional walkers do not incorporate the use of a basket to carry items. This cart, which is equipped with both a basket and casters, allows the client to work in the kitchen without relying on others.

TECHNICAL DESCRIPTION The cart is constructed of 1 3/8” PVC furniture-grade tubing. The PVC offers an attractive finish, while yielding the necessary strength and ease of assembly required in any project.

The padding on the rear support tube is vinyl over foam, mounted to the PVC frame.

The rear of the cart is free of obstructions. It incorpo-rates a basket for carrying kitchen items and food across the room. The basket is held in a slotted frame so that it can be removed, but will not slide out of po-sition when being used. The 4“ casters on which the cart rolls are mounted away from the user’s feet. Two of the casters are lockable.

The final cost of the Cart with basket was approxi-mately $75.

Figure 5.5. Cart with Basket.


CHAIR ADJUSTMENT Designers: James Wei, Shan Su, Lindsey Krough

Client Coordinator: Colleen Griffith, Johnson City School District Supervising Professor: Professor Richard S. Culver


INTRODUCTION Many school chairs are not adjustable to fit small children, especially those with physical disabilities. Standard back supports and footrests often leave children sitting too far from their workspace to pro-vide reasonable access. An adjustable foam back support and adjustable wooden footrest were con-structed to fit a standard school chair.

SUMMARY OF IMPACT A chair with adjustable back support and footrest will help small children.

TECHNICAL DESCRIPTION The device is made of foam and vinyl construction. The vinyl covers a series of removable thin foam sheets, allowing the vinyl pad to increase and de-crease in thickness, thus adjusting the depth of the back support/rest of the chair. A 2” nylon strap with buckle adjustment, sewn into the seams of the vinyl cover, attaches the pad to the back of a regular school chair.

The footrest is constructed primarily of wood with metal screw fasteners. The structure is attached to the existing legs of the chair by way of a clamping mechanism, which is adjusted using two hand fas-teners.

The final cost of the Chair Adjustment was approxi-mately $15.

Figure 5.6. School Chair to Accommodate a Small Child.


DOUBLE PEDAL BOARD Designers: Nnamdi Nwanze, Brian Lamond, Charles Kim, Craig Marcinkowski

Client Coordinator: Inalou Davey, Rehabilitation Services Inc., (RSI) Supervising Professor: Professor Richard S. Culver


INTRODUCTION The Double Pedal Board was constructed for clients who lack balance or have weakness on one side of the body. Patients may use it to gain strength on a weak side, and to gain balance.

SUMMARY OF IMPACT Many people lack strength on one side of their body or have trouble balancing while standing or walking. The Double Pedal Board allows a person who has unilateral weakness to gain strength. It also allows users with a lack of balance to gain balance by mim-icking a motion similar to walking or climbing stairs.

TECHNICAL DESCRIPTION The main structure of the Double Pedal Board is wooden. The handles are wooden, and are bolted to the main foot pedals, via screws and metal right-angle brackets. These brackets allow the user to put most of his/her weight on the handles without fear of falling.

The device consists of six wheels mounted opposite two pedal boards such that two of the wheels are lo-cated between the length of the boards and the other four are located outside of the pedal boards.

When the user presses down on one foot, the device begins to move forward or backward by way of four offset mounting pivots to which the pedal boards are attached.

The handles of the device are adjustable to accommo-date the height of many individuals.

The final cost of the Double Pedal Board was ap-proximately $50.

Figure 5.7. Double Pedal Board.


FOLDING CHAIR Designers: Karima Legette, James McFarlane, Martine Passe, Brian Muszynski

Client Coordinator: Judy Zeamer, High Risk Birth Clinic Supervising Professor: Professor Richard S. Culver


INTRODUCTION A three-year old girl needed a replacement for a fold-ing chair she had outgrown. The chair accommo-dates a potty seat, and has a folding mechanism for storage in an automobile.

SUMMARY OF IMPACT It is difficult to find ergonomic chairs for children with physical disabilities, especially chairs that are comfortable but compact and foldable. This chair can be taken in the car and used for a portable potty as well as sitting chair.

TECHNICAL DESCRIPTION The main structure is wooden, and has six compo-nents: the left arm, right arm, left folding support, right folding support, and front and rear main sup-ports. The six components are hinged so that the chair can fold in one piece. The chair locks into posi-tion through the use of two easily adjustable steel straps.

The seat of the chair is removable, and any compara-bly sized seat may be used, including the potty seat especially modified for this chair ( as shown in figure 5.8).

A 2“ thick footstool was supplied with the chair to al-low for use by smaller children.

The final cost of the folding chair was approximately $25.

Figure 5.8. A Foldable Adjustable Chair


HEAD SUPPORT FOR CHAIR Designers: Raymond Wong, Jake Liu, Brad Bungo, Tom McCabe

Client Coordinators: Colleen Griffith, Johnson City School District Supervising Professor: Professor Richard S. Culver


INTRODUCTION Many children with disabilities have difficulty sup-porting their heads properly. Lack of proper head support can lead to respiratory problems and neck and back difficulties as well as a number of other problems. A school district needed a head support that could be mounted on their existing Trip-Trac chairs. The head support needed to attach to the back of the chairs and be adjustable in height and for-ward/backward mobility.

SUMMARY OF IMPACT The add-on head support increases the usefulness of a Trip-Trac chair and makes it accessible to many more people who could otherwise not use this chair.

TECHNICAL DESCRIPTION The head support was constructed from a music-stand frame. The frame, while lightweight, is adjust-able in height, enabling the head support to be used by different people.

The actual headrest connects to the aluminum frame via an adjustable aluminum rod. The adjustment al-lows the user to sit with his/her head resting at mul-tiple angles.

The device clamps to the existing Trip-Trac chair via three small aluminum clamps designed such that no modification has to be made to the original chair.

The headrest is constructed of foam and vinyl, with a thin sheet of aluminum within for basic structural support.

The final cost of the headrest was approximately $30.

Figure 5.9. Head Rest Attachment for the Trip-Trac Chair.


THE HEAD SWITCH Designers: Tony Huang, Izhar Ahmad, Alok Bhalla, Jason Yuen Client Coordinator: Beth Peck, ARC Day Treatment Program



INTRODUCTION A head switch was designed to enable a patient to turn music on and off at will without the help of an-other person.

SUMMARY OF IMPACT The head switch allows the client to control her music independently.

TECHNICAL DESCRIPTION The switch is a plastic hinge with a micro switch screwed on to one of the inner sides. As the hinge is pressed, it in turn presses on to the micro switch, ac-

tivating the circuit. The plastic base is firmly screwed against a half-inch plywood board. The bot-tom part of the wooden board is fitted with Velcro. A facing Velcro strip is attached to a beanbag. Finally, four parallel slits are drilled and filed into the curved plastic base. Two nylon straps are then inserted through these slits, and two pairs of complementary buckles are attached to either end of the straps. The straps secure the device to the headrest.

The final cost of the Head Switch was approximately $15.

Figure 5.10. Head Switch.


ADJUSTABLE PENCIL GRIPPER Designers: Mike McCarthy, Tamir Ratzon, David Lomonaco, Hsing-I Lin

Client Coordinator: Bonnie Cole, Handicapped Children’s Association Supervising Professor: Professor Richard S. Culver


INTRODUCTION Some young children with limitations in the use of their hands have difficulty grasping small objects such as pens and markers. A hand-held gripper for writing instruments was constructed to address this problem. The handle of the pencil gripper is perpen-dicular to the writing instrument, which allows the user to lay his or her hand on the table while writing.

SUMMARY OF IMPACT A pencil gripper enables small children and those with physical disabilities to work more accurately with small writing instruments.

TECHNICAL DESCRIPTION The gripping portion of the pencil gripper is made from a modified beaker holder. The holder is in-stalled inside a one-inch diameter PVC tube. The thumbscrews used to compress the jaws on the beaker

holder are replaced with a heavy rubber band that keeps the jaws closed. A writing instrument is in-serted between the two fingers of the beaker holder. The handle is coated with rubber tape for a stronger grip. The device can accommodate writing instru-ments with an outside diameter from #2 pencil size to ¾ inch.

The final cost of the adjustable pencil gripper is ap-proximately $10.

Figure 5.11. Adjustable Pencil Gripper.


PUPPET THEATRE Designers: Michael Begic, Erik Springer, Pamela Ayoub, Brian Vallimont

Client Coordinator: Penny Baldwin, BOCES at Appalachian Supervising Professor: Professor Richard S. Culver


INTRODUCTION A medium sized puppet theatre was constructed for children with autism. The theatre is portable, yet sturdy, incorporates internal lighting, and has a re-tractable curtain.

SUMMARY OF IMPACT The puppet theater provides a unique way for chil-dren with autism to express themselves. In addition, this theatre provides wholesome entertainment for many children.

TECHNICAL DESCRIPTION The main structure is made of pine and ½” birch plywood. Metal cornering brackets provide internal

structural stability. The result was a lightweight, sturdy puppet theatre.

The theater has three internal lights, red, green, and blue. Each light, operated with its own switch, al-lows the users to modify the mood and tone of the theatre.

An adjustable curtain rod with pull cords has been modified to make it possible for the user to open and close the curtains from the rear of the theatre.

The final cost of the puppet theatre was approxi-mately $100.

Figure 5.12. Puppet Theatre.


SCOOTER BOARD Designers: Steven Violante, Derrick Farfan, Rebecca Knowlton, Nova Greenberg

Client Coordinators: Donna Boisvert, Vestal School District (VSD) Supervising Professor: Professor Richard S. Culver


INTRODUCTION A was designed to enhance students’ mobility. A removable frame with straps allows a child who can-not support him/herself to ride. It is adjustable to ac-commodate children of different sizes.

SUMMARY OF IMPACT Scooter boards are small platforms with wheels mounted on the bottom. Individuals can sit or lie down on the board and push themselves along in any direction using their hands.

This particular scooter board permits the user to op-erate in either a sitting or lying position, a feature not incorporated in existing scooter boards.

TECHNICAL DESCRIPTION The device is constructed of PVC, foam, and cloth, as well as ¾” pine board. The pine board serves as the structural mainstay of the device, with the wheels mounted onto the board. The board is divided into

two sections combined together using hand tightened wing nuts. The split bottom of the device allows the user to adjust its length.

The back of the device is constructed of PVC and cloth. The PVC acts as the main support, while the cloth, which is stretched taut across the PVC support frame, acts as a backrest.

Also included in the design are multiple nylon straps to secure the user to the device, as well as multiple foam back supports for cases when the user rides in a prone position.

The final cost of the project was approximately $35.

Figure 5.13. Scooter Board.


SIT-AND-SPIN TOY FOR LARGER CHILDREN AND ADULTS

Designers: Kristen Beal, Eric Stellrecht, Kevin Stein, Stephanie Deckter Client Coordinator: Donna Boisvert, Vestal School District (VSD)



INTRODUCTION A Sit-and-Spin toy was designed for use by larger children and adults. Similar toys on the market are too small and are made of plastic materials that fail under loads of larger children and adults.

SUMMARY OF IMPACT A Sit-and-Spin is a fun toy that enhances hand-eye coordination and upper body strength.

TECHNICAL DESCRIPTION The device is constructed of luan mahogany ply-wood, PVC tube, an extra large commercial thrust bearing, and plastic casters with metal frames.

The main platform of the device is constructed using the plywood. Underneath the main platform are mounted four casters, with their line of travel tangen-

tial to the circular base. While the casters relieve some of the load on the base of the Sit-and-Spin, the use of a thrust bearing was deemed necessary for smooth op-eration. Thus in the center of the main platform a thrust bearing is mounted to disperse most of the load in the center of the toy while providing a smooth roll-ing motion. The center shaft of the device is con-structed of PVC tube. A simple bolt mechanism and holes along the center shaft allow for easy adjustment of handgrip height.

The final cost of the Sit-and-Spin is approximately $90.

Figure 5.14. Sit-and-Spin Toy for Larger Children and Adults.


STAND-PIVOT SYSTEM Designers: Vincent Lee, Matt Yavorsky, Christopher Yatrakis, Peter Joo

Client Coordinator: Valdo Rogers, Broome Development Center Supervising Professor: Professor Richard S. Culver


INTRODUCTION A stand-pivot system was designed to easily and safely transfer clients to and from wheelchairs and beds.. The Broome Development Center works with many people who have difficulty transferring from a wheelchair to a bed. The difficulty increases when the individual has limited control of his/her legs. The individual’s feet often bind on the floor during the rotation that takes place in the transfer.

SUMMARY OF IMPACT The device, a flat freely-spinning disk mounted close to the floor, enables the easy rotation of one’s body to facilitate the safe transfer of individuals to and from wheelchairs and beds.

TECHNICAL DESCRIPTION The device is constructed of 3/16” PVC plastic sheet-ing (Figure 5.15). Two pieces of this strong yet flexible material are mounted together using standard com-mercially available thrust bearings.

The bottom and top surfaces of the device are coated with non-slip tape to further enhance the safety of the device.

The final cost of the stand-pivot system to transfer cli-ents to and from wheelchairs and beds was approxi-mately $17.

Figure 5.15. Stand-Pivot System.


FLOTATION BELT Designers: Todd Young, Miheer Fyzee, Catherine Ma, Erica McKenzie

Client Coordinator: Colleen Griffith, Johnson City School District Supervising Professor: Professor Richard S. Culver


INTRODUCTION A buoyancy system was designed to allow a client with cerebral palsy to be held at the correct orienta-tion and with the minimum buoyancy needed to maintain proper swimming form.

SUMMARY OF IMPACT The flotation belt replaces an improvised swimming belt that was unsightly and difficult to use. This belt is attractive and easy to adjust. It has contributed to the client’s progress in a special swimming program.

TECHNICAL DESCRIPTION The device, designed for children with cerebral palsy, is mainly composed of nylon and Styrofoam. Two straps with adjustable buckles allow the device to be

used with a wide variety of children.

The device is also adjustable in other ways. Multi-part Styrofoam pads that slip into the nylon allow any number of Styrofoam pads to be used to adjust the flotation of the device for children of various weights. Also, the straps can be adjusted to hold the device at different positions on the user’s torso.

The final cost of the swimming aid was approxi-mately $15.

Figure 5.16. Flotation Belt.


TABLE FOR BENNETT BENCH Designers: Will Wojtkielewicz, Robert Polak, James Gale, Patrick O’Meara

Client Coordinator: Inalou Davey, Rehabilitation Services Inc., (RSI) Supervising Professor: Professor Richard S. Culver


INTRODUCTION The Bennett Bench is a device for exercising bi-manual manipulation skills. A lightweight, rigid, ad-justable table was built so that more people with dis-abilities can use the Bennett Bench equipment.

SUMMARY OF IMPACT The adjustable Bennett Bench table provides much needed access to the Bennett Bench for people who currently cannot use it due to height restrictions. The adjustable stand allows different users to use the Ben-nett Bench.

TECHNICAL DESCRIPTION The frame of the Bennett Bench table is made of 1 3/8” furniture-grade PVC tubing. Incorporating tele-scoping tubes, the frame is adjustable to accommo-date varying heights of sitting and standing users. The bottom of the table uses PVC end caps to ensure stable footing. The table surface is ¾” luan mahog-any plywood.

The final cost of the Table for Bennett Bench was ap-proximately $40.

Figure 5.17. Adjustable Table for the Bennett Bench


ADJUSTABLE MULTI-USER COMPUTER STATION

Designers: Ben Huang, Mohammed Kashef, Paul Marinello, Robert Lockwood Client Coordinator: Beth Peck, ARC,

Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION The differing heights of wheelchairs make it difficult to tailor workstations for multiple users. A sheltered workshop needed a multi-user station to accommo-date many individuals in wheelchairs of varying heights.

SUMMARY OF IMPACT The device enables people with different working heights, due to varying wheelchair sizes, to work on the same workstation

TECHNICAL DESCRIPTION A four-person desk-type unit allows each person to work at a different height. Each desk incorporates

boxes for storage, located on the top of the unit, as well as an adjustable wooden tabletop. The tabletop was mounted on commercial, adjustable steel shelv-ing brackets similar to those used for bookshelves.

The structural frame of the device was designed to be easily collapsible if the need for low-space storage arises. It is made out of clear pine lumber. The feet are foldable, and the shelves are easily removed as well.

The final cost of the device was approximately $80.

Figure 5.18. Adjustable Multi-User Computer Station.


WHEELCHAIR STORAGE RACK Designers: Yassir Hussain, Jared Miller, Jae H. Park, Tim Schlauraff

Client Coordinators: Valdo Rogers, Broome Development Center Supervising Professor: Professor Richard S. Culver


INTRODUCTION A storage rack was built to support eight wheelchairs. It allows for easy access to the wheelchairs and eliminates damage due to haphazard stacking.

SUMMARY OF IMPACT Wheelchairs are costly and difficult to repair. Proper storage of these essential devices is necessary to pre-serve and maintain them. This rack represents a ma-jor improvement to the management of wheelchairs at a developmental center.

TECHNICAL DESCRIPTION The device, designed to meet strict fire code require-ments, is composed entirely of steel fence posting. Strong and lightweight, this material is both func-tional and aesthetically pleasing.

The device consists of basic box-frame construction, with joints composed of standard fencing elbows. The rack has three horizontal rails. Two rails hold the large rear wheel, while the third, which is slightly higher than the other two, supports the wheelchair frame behind the small front wheel.

The device, while relatively compact, can store up to eight wheelchairs: four on top, and four below.

The final cost of the wheelchair storage rack was $283.

Figure 5.19. Wheelchair Storage Rack.


FOOT-PROPELLED WHEELCHAIR Designers: Philip Suarez, Vincent Look, Joel Almonte, Robert Bracero

Client Coordinator: Terry Terrell, STIC Supervising Professor: Professor Richard S. Culver


INTRODUCTION The foot-propelled wheelchair was built for an elderly woman with cerebral palsy who prefers to propel her-self with her feet. Her existing wheelchair was in disrepair and did not allow easy foot movement.

SUMMARY OF IMPACT A wheelchair with free space for feet allows the user to propel herself without using her hands. This new wheel chair improves her mobility and is an attractive alternative to the one she was using.

TECHNICAL DESCRIPTION The wheelchair frame is constructed of 1 3/8” furni-ture-grade PVC tubing. The PVC offers an attractive finish, while incorporating the necessary strength and ease of assembly required in any project.

The padding of the chair is vinyl over foam, which is supported on the PVC frame with 3/8” plywood.

The front of the chair is free of obstructions, unlike conventional wheelchairs, and the casters on which the chair rolls are mounted away from the user’s feet.

The two rear casters are lockable and are frozen so that they only track forward.

The final cost of the Wheelchair is approximately $60.

Figure 5.20. Foot-Propelled Wheelchair.


ADJUSTABLE WALKER Designers: Seamus Gorman, William Schumacher, Jessica Terry

Client Coordinator: Colleen Griffith, JCSD Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION An adjustable walker was designed for children with developmental delay.

SUMMARY OF IMPACT A walker device was needed to help children main-tain their balance while walking. The multiple-use stabilizing device can be used by children of varying sizes. Varying amounts of tension can be placed on the wheels to match the child’s ability. The resistance can be lessened as the child gains strength and walk-ing skills. This allows for a gradual progression of becoming less dependent on the walker. Once the child masters the coordination that is required to walk with no tension, the swivel lock can be disabled to allow the child to learn how to change directions. The walking process is simplified into manageable and yet challenging steps that can be isolated and then mastered.

TECHNICAL DESCRIPTION The children’s walker was designed to be used by more than one child. Therefore, many of the features of the walker are adjustable. The main requirements were that it: 1) support the weight of a child up to 50 pounds, but not provide so much support that the child would become dependent upon the device; 2) be lightweight enough so that it is portable and maneu-verable; 3) be durable and easy to maintain; 4) allow enough room for the child to walk behind it with a 12” wide clearance for feet; 5) have a handle of about ¾” diameter with a height adjustment range of 1½-2’; 6 work on both hardwood floors and carpet; 7) have adjustable wheels resistance; 8) have a steering and rigid mode as well as wheels which only roll forward; 9) permit any adjustments to be made in under five minutes; and 10) be safe.

The walker has a 20”x20” U-shaped base with two 20” posts rising from the middle of the two long sec-tions of the U. These posts are secured to the base and the handle is mounted to the two posts. Four pivoting casters are mounted to the corners of the U. The entire frame is constructed from 1¼” furniture grade PVC piping. Slip Tee and internal elbow fit-tings are used to join the members of the frame. Holes in the posts at 1” spacing allow vertical adjustment of the handle. The handle, constructed from ¾” PVC tubing, is screwed into Slip Tee joints, which fit over the posts.

The two rear 2” casters do not pivot. A screw can be forced against the surface of the caster to provide ad-justable resistance and can be used as a stop when screwed all the way down.

The two front swivel 2” casters feature a swivel lock, which allows the wheels to have a rigid and a steer-ing mode. In order to create this device, a ½” thick aluminum block was cut in a C-shape, which fits snugly around the wheels. A hinge connects the caster mounting plate to the aluminum block. This al-lows the block to rotate down onto the wheel and lock it in a fixed position, or to rotate up and allow the wheel to swivel freely. An elastic band holds the block in place when the caster is allowed to pivot.

The total weight of the device is 8.7 pounds.

The cost is $67.00. A similar device is available on the market, but not with all of the features that this walker offers for such a low price.


Figure 5.21. Adjustable Walker.


AUTOMATIC ROCKER FOR AN EASY CHAIR Designers: Jared Waugh, Ricky Lu, Ariel Reiter

Client Coordinator: Valdo Rogers, Broome Development Center Supervising Professor: Richard S. Culver

Binghamton University Binghamton, NY 13902-6000

INTRODUCTION An automatic rocker was made for a twenty-year-old man with autism. It fits under the lower rear edge of an overstuffed rocking chair. It consists of a rotating arm on a small gear motor, mounted in a frame that sits on the floor. When operating, the rotating arm pushes up on the seat through a rolling bearing.

SUMMARY OF IMPACT Previously, the client’s caregiver found that when he rocked the chair with his foot, it calmed the client. The Automatic Rocker relieves the caregiver of having to rock the chair.

TECHNICAL DESCRIPTION Measurements of the range of motion of the chair and the natural frequency of the rocker indicated that the vertical travel is 3” at a frequency of approximately 39 rpm. The maximum vertical force required to obtain this displacement is 20 pounds. Using this informa-tion, a gear motor, which runs at 35 rpm and has a maximum torque rating of 30 inch- pounds, was se-

lected. The motor is attached to a 5/8” plywood frame, which extends under the chair. A 1/2" diame-ter shaft extension is mounted on the motor. The 2" aluminum crank arm supports another 1/2" shaft at a distance of 1 1/2 " to provide the needed vertical mo-tion. A 3/4" diameter PVC sleeve which slips on the crank provides a moving bearing to reduce friction be-tween the bottom of the chair and the rotating arm.

Because of the geometry of the system, the maximum vertical force of 20 pounds is applied when the crank moment arm is of zero length. The maximum applied torque occurs at 45o above horizontal. It is calculated to be about 10 inch- pounds, which is well within the capacity of the motor, particularly since the motor only applies this torque for a small portion of each ro-tation.

The motor assembly has a wooden cover, with metal screen ends to allow for ventilation.

The total cost of the automatic rocker is $75.


Figure 5.22. Automatic Rocker for an Easy Chair.


CLIMBING WALL FOR YOUNG CHILDREN Designers: Brian Ide – Junior, Matthew DuBord, Jason Borgen, Daniel Roesser, Allan Assuncion

Client Coordinator: Laura Cline, Handicapped Children’s Association Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION An adjustable climbing wall was constructed for use by children. Eight feet high and 6 feet wide, it is at-tached to a tubular steel frame, which allows it to be set at different angles. A variety of handles and handholds are provided on the face of the wall to as-sist children in climbing on it. A horizontal bar at the top of the wall provides an anchor for a climbing rope, which is attached to a climbing harness on the child. The frame is designed to allow one or two therapists to be on the wall with the child to assist in climbing. The wall surface is covered with linoleum to provide a smooth surface that will hold plastic-based stick-on cartoon characters, enhancing motiva-tion for climbing.

SUMMARY OF IMPACT Climbing walls provide an ideal activity for children with limited physical ability to stimulate hand/eye coordination and to build upper body strength. The climbing wall takes up much less space than a jungle gym and provides a single controlled surface upon which a child can exercise. Its flat surface provides a convenient means for the therapist to provide active support while the child is climbing.

Figure.5.23. Climbing Wall at 60o Angle.

Figure 5.24. – Upper Frame Support


TECHNICAL DESCRIPTION The climbing wall surface is made of two 4’x 6’, ¾” plywood panels. Holes 5/8” diameter, are drilled in the panels in a regular pattern to provide anchor points for the handholds. Footholds are also cut into the surface of the wall. The wall is covered with a tan, pebble-patterned linoleum that resembles a rock wall.

The panels are mounted on a moving frame made from 1”. square tubular steel. Three-inch casters are mounted on the bottom of the frame. A ½” steel rod runs across the top of the frame and extends past the end of the frame an additional inch to provide the upper sliding anchor. Plastic tubing on the rod pro-vides the sliding surface. The matching steel tubular frame attached to the wall has a steel l-shaped angle welded to the side to provide a channel for the plastic

covered anchors. Eye-bolts attached to the lower ex-tremities of the fixed frame on the wall and the mov-ing frame are used to anchor a heavy-duty steel chain which allows the wall to be supported at different angles from the wall.

Two types of handgrips are used. Children’s’ tricycle handgrips are slid onto 5/8” bolts protruding through the wall. Wooden handgrips made from lumber and covered with fiberglass are also used. The fiberglass resin was dipped in sand when wet to make a nonslip surface. A 5/8” bolt attaches the handgrips to the wall. These can be moved around the wall to create the desired climbing pattern.

The cost of materials for the climbing wall is $275.

Figure 5.25 – Caster on Lower Leg of Climbing Wall.


COLLAPSIBLE CANE FOR THE BLIND Designers: James Keane, John Nenadic, Dave Allen

Client Coordinator: Dave Scudder, Intellidapt Supervising Professor Professor Richard S. Culver

Department of Mechanical Engineering Binghamton University

Binghamton, NY 13902-6000

INTRODUCTION A new design was developed for a collapsible cane for individuals with blindness. Joints using a metal hinge with a bungee cord running through the center replace the traditional slip joint.

SUMMARY OF IMPACT Commercially available folding canes for use by indi-viduals with blindness are made of aluminum tubing. One end of each tube is reduced in cross section so that it fits inside the next tube. An elastic bungee cord runs through the entire cane to pull the individual tubes together. In use, the sharp edge of the tube can eventually cut through the bungee cord. Also, the tube joint often becomes loose from repeated assembly and bending. The joints are not strong. If loaded lat-erally, the joints can bend or open up. The cane built in this project uses a more robust joint, which works in a manner similar to the traditional cane. In a field trial, someone accidentally stepped on the cane, but it did not break, confirming the strength of the joint. This cane design will permit longer use and more user confidence than current commercial models.

TECHNICAL DESCRIPTION One side of the yoke and tongue hinge can slide out while the other is fixed. The elastic bungee cord that holds the joint together when assembled passes through the hinge pieces. To operate, the user pulls the two tubes apart, stretching the bungee cord. When the hinge joint is clear of the nesting tube, it can be folded. The joint parts are made of aluminum, as is

the shank of the cane. The cane tubular wall was re-duced in thickness between joints in order to reduce the weight of the cane. This cane weighs approxi-mately the same as commercial canes.

The cost of materials was approximately $25.

Figure 5.26 – Collapsible Cane in Use.


Figure 5.27 – Joint on Collapsible Cane.


ELECTRONIC LOCK Designers: Abraham Howell, Dairusz Filak, Jose Tova

Client Coordinator: Colleen Griffith, JCSD Supervising Professor: Professor Richard S. Culver

Department of Mechanical Engineering Binghamton University

Binghamton, NY 13902-6000

INTRODUCTION An electronically operated lock system was designed and built to attach to a regular locker door.

SUMMARY OF IMPACT The client is a 13-year-old female middle school stu-dent with cerebral palsy. She could not open her school locker due to her limited manual dexterity with the combination lock. The electronically acti-vated rotary lock system on allows her to open the locker on her own from her wheelchair.

TECHNICAL DESCRIPTION An actual locker door was removed from its frame to facilitate installation. The handle was removed and new holes were drilled to allow for the mounting of a tubular solenoid actuator. A receiver and transmitter from Power Door products provide the electronic con-trol for the lock. When the small, handheld transmit-ter sends a signal to the receiver, a relay in the re-ceiver is closed. The relay sends power to the 12-volt door actuator, which opens the rotary latch.

The receiver requires 24 volts and the solenoid actua-tor, 12 volts. Transformers to provide these voltages are mounted in the ceiling and attached to a 110-volt duplex outlet.

All sharp edges are removed from the door and lock fittings to prevent injury. The handheld transmitter is mounted with Velcro to the client’s wheelchair. The transmitter has a large button.

The final cost of the Key Lock Mechanism is ap-proximately $175.

Figure 5.28. Electronic Lock.


A RACE CAR FOR CHILDREN Designers: Kevin Kressner, Lauri Tacadema, Michael Mainville Client Coordinator: Mary O'Dell, BOCES Appalachin School



INTRODUCTION A commercial four-wheeled pedal car was modified for use by elementary school students. The car has an adjustable seat and a PVC body that folds back to permit easy access.

SUMMARY OF IMPACT A pedal car was designed for students to use in physical therapy and recreation programs. The school was unable to afford an equivalent commer-cially available vehicle. The students vary in ability, size and weight (from 4'6" to 6' and from 100 to 250 pounds). The car allows several students to ride on the playground.

TECHNICAL DESCRIPTION For safety reasons, a commercial frame was used. It was purchased from Quadracycle, in Hamilton IN.

Made of rectangular steel tubing, it is designed for a single rider and has a regular steering wheel and hand brake. It has 16" balloon tires. Local fabrication involved the design and construction of a PVC body, attached to the frame with hinges and latches. PVC sheet, 1/8" thick, was hand formed using a heat gun. The shape of the body is carefully designed to permit use of straight bends. The hood is mounted with hinges so that it can be raised to assist the driver in entering the car.

Upon completing the construction, the body was spray-painted racing green.

Cost of the pedal car is $495. The PVC plastic sheet, fittings and paint cost $70. The total cost of materials is $565.

Figure 5.29. Race Car.


POOL LIFT FOR SMALL CHILD Designers: Matthew Rubin, Christopher Conklin, David Wong

Client Coordinator: Judy Zeamer, High Risks Birth Clinic Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION A fiberglass seat, which can be lowered by hand into a swimming pool, was made for a four-year-old girl with cerebral palsy. The seat is attached, by pivoting arms, to a PVC tubular frame that is clamped to the wooden deck surrounding the swimming pool. In use, the girl is strapped into the seat at the poolside. The seat is then lifted by a bar (molded into the top of the chair) and rotated until it is over the water. The seat is then lowered into the water. A clamp on the vertical guidepost controls the depth of submersion.

SUMMARY OF IMPACT The client’s use of the pool had been limited because she cannot support herself in an upright position. The lifting mechanism makes it possible for her par-ents to easily lower her into the water. The lift pro-vides a safe means by which the client can enjoy the water and participate in water play with her friends.

TECHNICAL DESCRIPTION The pool lift is made from PVC plastic tubing and fi-berglass. The seat is formed from fiberglass, using a wooden frame, molded around two PVC tubes, which connect the seat to the supporting frame. On the end of the two horizontal PVC tubes, Slip Tees are held

with bolts. These Tees allow the seat to move verti-cally and rotate around the main vertical post. The main post consists of a PVC tube with an internal steel electrical conduit and spacer for stiffening. On the bottom of the conduit is a 16-pound steel disk that anchors the post to the pool bottom. The disk and conduit are coated with rubber to prevent rusting. The top of the vertical post is attached to a PVC frame that is bolted via a PVC flange to the wooden pool deck. The supporting frame is attached to the vertical post using slip joints with spring buttons so that the post can be removed for storage.

The frame and seat cost approximately $90.


Figure 5.30. Pool Lift.


PORTABLE SWIMMING POOL STAIRS Designers: Jason Mooney, James, Bush, Jonathan Curtin Client Coordinator: Sheila Zuba, Johnson City YMCA

Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION A portable stairway was designed and built to pro-vide access to a swimming pool for people with lim-ited mobility.

SUMMARY OF IMPACT Many of the participants an active water therapy pro-gram for senior citizens are heavy and have difficulty getting into and out of the pool. The portable steps previously used were very steep. Rising above the pool level, they were especially difficult to negotiate. An expensive commercial pool stairway system had been purchased but did not work. The stairway built in this project is so popular that people were upset when it was removed for refinement.

TECHNICAL DESCRIPTION The pool stairway is constructed from 2" x 6" fiber-glass channel. The channel is used for the side run-ners and double width channels form the steps. The actual rise for each step is 6”. By hooking the stair-way to the rolled stainless steel edge on the pool with a matching stainless steel lip, it was possible to mini-mize the number of steps. The stairway has to fit between the end of the pool and the permanent lad-der, which is about 8‘ from the end of the pool. The steps are attached to the runners with flanges made from channel material. A 3/4" diameter PVC tube is mounted to the bottom of each runner to provide a skid to assist in lowering the stairway into the pool. The stairway is painted bright yellow with epoxy paint.

When the stairway was completed, it was found to be stiff enough in bending but had low torsional rigidity. Plexiglas panels were thus mounted between adja-cent steps as stiffeners. This significantly improved the rigidity.

Figure 5.31. The Pool Stairway in the Water.

Figure 5.32. Pool Stairs on Deck.


The rails are made of reinforced furniture-grade PVC tubing. Steel electrical conduit with spacers is placed in each vertical support. Threaded aluminum joints were matched to the conduit to provide longitudinal stiffening in the lower horizontal rail. The rails are attached to the side of the stairway using PVC Tees.

The stainless steel lip, which holds the stairway to the edge of the pool, was made commercially from 20-gauge sheet. When the steps were installed, it was

found that the lip slowly deformed under load and unwrapped from the pool edge. The lip was rerolled and a PVC frame was constructed to sit under the uppermost step on the stairway. When the lip slips approximately 0.05" under load, the frame takes the load. This insures that the lip is tightly attached to the edge so that it will not slide sideways.

Total cost of the pool stairs is $975.

Figure 5.33. Attachment of the Handrail to the Stairway Frame.


PRESSURE VEST Designers: Ellen Dulberg, Fredric Johannesen, Steve Rossi

Client Coordinator: Christine Breslin, HCA Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION A Pressure Vest was designed for young children with autism. The device is mechanical. The child places the vest around his/her torso and applies pressure by rotating a hook, which then pulls the front of the vest together. Studies have shown that this type of pressure technique may be therapeutic in some cases. The interior of the vest is made of foam and steel ribs, surrounded by canvas on the exterior. The ribs provide rigidity. The child controls the de-vice, but is under adult supervision at all times.

SUMMARY OF IMPACT Deep pressure therapy is sometimes used with the in-tent to satisfy the need of individuals with autism for tactile stimulation. Pressure is slowly applied over the individual’s body for a calming effect. Experts consulted were clear that this method of treatment is not a universal solution to the needs of individuals with autism. Although the vest provided the desired pressure on a small child, use was discontinued be-cause of the risk of causing internal injury. Without appropriate feedback there is no effective way to pro-tect the child.

TECHNICAL DESCRIPTION The dimensions of the vest were based on measure-ments of average three- to five-year-olds in a local preschool (24” (± 3”) around the waist, and 10½” (± 1”) from armpit to hip). The vest is 30” in length when laid out flat, and 10” high.

The tightening/pressure applying mechanism con-sists of a hook and a hitch (Figure 5.33), made from aluminum and mounted directly on the ribs of the vest. The handle on the hook has a swivel knob for easy operation. There is an overlap on the back of the vest in order to make the vest adjustable to fit children of differing sizes.

There are belt loops on the back of the vest so the child can be immobilized by using a winch strap. The hook’s radius decreases from 3” to ½”. The pres-sure is applied to the torso when the child rotates the handle. The decreasing radius will pull the two sides of the front of the vest together. As seen in Figure 5.34, part of the hook has a constant radius. This as-sists the supervisor in inserting the hook into the hitch.

The supervisor puts the vest on the child and inserts the part of the hook with a constant radius onto the hitch. Then the supervisor tightens the buckles in the back of vest to fit the child, and immobilizes the child with the winch strap. Next, the child rotates the han-dle to increase or decrease the pressure. To get out of the device quickly, the child may simply rotate the handle all the way back until the hook comes out of the hitch.

The total cost of the vest was approximately $165.00. The majority of the cost was for tailoring expense.

Figure 5.34. Pressure Vest showing rear adjust-ment straps.


Figure 5.35. Pressure Vest with Adjustable Mechanical Latch.


BLOW-STRAW UNIVERSAL REMOTE CONTROL Designers: Daron King, David Peek, Roger Richardson

Client Coordinator: Inalou Davey Supervising Professor: Richard S. Culver Department of Mechanical Engineering


INTRODUCTION A universal remote control device was designed to accommodate the needs of a client with quadriplegia who is visually impaired. The remote consists of two modular components, the frame and the remote box. The frame is H-shaped, consisting of two bases with vertical posts, and a cross-member that holds the re-mote box in place. The cross-member is composed of two parallel bars, which are offset horizontally, and slip joints, which connect the cross-member to the ver-tical posts. The cross-member is adjustable in height and also removable for storage. The remote box con-sists of four input straws and an output display. De-sired results are achieved by blowing or “puffing” through the insert straws. The output display con-sists of two series of large, colored LED lights, which illuminate in conjunction with the device’s functions. The colored lights are used to accommodate the vi-sion impairment, since text labels are unreadable. The remote allows the client to operate a television, cable, radio, and CD player through infrared light. Four additional devices can be added.

SUMMARY OF IMPACT The blow-straw remote is a relatively inexpensive and versatile device that provides individuals with quad-riplegia the freedom to change their environment even when they are alone. The ability to connect addi-tional devices to the remote in the future will allow the client to continually expand his/her environ-mental interaction and control.

TECHNICAL DESCRIPTION The blow-straw remote was designed to accommo-date a particular client, but could be used by almost anyone who is seated upright in a chair or recliner. The design constraints presented specifically by our client were that it: 1) be operational without using any body motion except head movement; 2) not use

Figure 5.36. Universal Remote Control Stand in Use by Client.

Figure 5.37. Operator’s View of Remote Control Housing.


text labels or displays, due to the client’s poor vision; 3) be adjustable such that it will accommodate a vari-ety of different chairs that the client may choose to sit in; 4) be universal and able to adapt to new au-dio/video equipment; 5) not require assistance at any point beyond its initial set up, because the client is alone for most of the day; and, most importantly, 6) be safe.

The frame for the remote control is H-shaped, and has two vertical posts with bases and a cross-member. The vertical posts are two 40” tall 1¼” PVC members, anchored by aluminum bases. The bases are cylin-drical, each 12” in diameter and 1” thick. They are mounted to the posts using steel flanges and four bolts. The cross-members consist of two horizontal 36” long 1¼” PVC members that span the width of the chair or recliner. These members are connected to the posts by four 45-degree elbows and short PVC exten-sions, which lead into two modified “slip V’s”, one on each post. PVC platforms and rubber stoppers, in conjunction with hose clamps, are used to adjust the height of the slip V’s. This allows the height of the cross-members to be finely tuned as opposed to being adjustable in increments.

The remote box was built using 1/8” thick sheet PVC and assembled using L-brackets and mounting hardware. The final box dimensions are 10” x 14” x 4”. Sheet PVC is also used to wall off two separate compartments in the box, one that holds the remote’s circuitry, and another that houses the blow-straw switches. This is a safety feature to prevent moisture from coming into contact with the circuitry.

Two access doors are built into the box, one to access each compartment. The remote circuitry is from a re-tail universal remote control with logic gates that de-cipher input from the blow-straws. The blow-straws are ¼”-diameter tubes that lead into the box and into a

larger air diffuser. A plunger in the diffuser de-presses a switch when the client blows on the tube. These switches are wired into the remote circuitry in the other compartment.

The remote box is attached to the cross-member by four custom made U-mounts that permanently at-tached to the bottom of the box. These mounts snap over the cross-members and hold the box in place, while allowing the box to be easily removed or slid across the cross-members. A large digital clock is also mounted on the cross-members using a sheet PVC platform and two custom made U-mounts.

For safety reasons, all edges on the remote box and frame were filed and/or rounded. Also, 1¼” PVC caps were mounted on the tops of both vertical posts. The caps enhance the frame’s appearance and cover the rough edge of the open-ended PVC members. A client with quadriplegia tested the frame and box for use and found the apparatus to be effective. It has been suggested that we also install vents in the blow-straw compartment of the box to avoid moisture ac-cumulation and improve safety.

A 7.5V AC/DC adapter powers the circuitry of the logic circuit. Using a low voltage DC source de-creased the chance of shock or electrocution. The universal remote circuitry is powered by two AA batteries, which also have a minimal shock potential. The digital clock is a separate unit, powered by a standard AC plug. The clock does not constitute an electrical hazard.

The final cost of the remote device is approximately $115.00, not including labor charges. Many of the components were made from scrap materials avail-able at no cost.


WHEELCHAIR SWING Designers: Jamie Kimberley, Michael Maelum, May Ng

Client Coordinators: Mary Odel, BOCES at Appalachian Supervising Professor: Professor Richard S. Culver


INTRODUCTION A wheelchair swing (Figure 5.38) was designed for children with disabilities. The swing moves in a par-allel motion to the floor and is powered by human force at the present, but can be modified in the future to accommodate other power sources. The unit was built to be easily disassembled and stored.

SUMMARY OF IMPACT The wheelchair swing provides clients new oppor-tunities for stimulation and a recreation during their indoor classes. It was designed for school-age chil-dren, but could be beneficial to others.

TECHNICAL DESCRIPTION The main design requirements were that the wheel-chair swing: 1) be as small as possible, due to the lim-ited amount of classroom space; 2) be portable, easily disassembled and stored out of the way; 3) accommo-date all sizes and types of wheelchairs; 4) be safe to use.

The swing has two main components, the frame and the platform. The frame is a rectangular structure

consisting of 1-5/8” steel conduits connected with cast aluminum fittings. These structural pipefittings secure the pipe via allen bolts. Connected to the frame are two 1/8” plastic coated steel cables to stabi-lize the swing during motion. The platform is a 30” x 50” x 3/4” piece of plywood reinforced with steel and connected to four supporting 1/8” plastic coated steel cables for stability. Connecting the cables are 1/8” cable clips, 3/8” spring snaps, and 5/16” eyebolts. The clips allow for quick disassembly. There is also a small railing on the platform and tie-down straps on the platform to immobilize the wheelchair to the plat-form. A small ramp has been attached to the platform to load and unload the client.

Tests of the swing were conducted by having mem-bers of the design team weight the platform to the simulated weight of the clients while the swing was in motion. A design change for the future is to de-velop a freestanding swing that is portable for indoor and outdoor use. The swing might also be motorized.

The final cost of the wheelchair swing was approxi-mately $165.


Figure 5.38. Wheel Chair Swing.

77

CHAPTER 6 DUKE UNIVERSITY

School of Engineering Department of Biomedical Engineering

Durham, North Carolina 27708-0281


Laurence N. Bohs (919) 660-5155 [email protected]


SENSORY STIMULATION ACTIVITY CENTER Designers: Anna Fernandez, Elaine Hsieh, & Wesley Joe

Client Coordinators: Mary Caldwell & Lenore Champion Duke Hospital Pediatric Rehabilitation Center Supervising Professor: Dr. Laurence N. Bohs

Department of Biomedical Engineering Duke University

Durham, NC 27708

INTRODUCTION A Sensory Stimulation Activity Center (SSAC) was developed for use in the treatment of children under three with Down’s Syndrome or closed head injury. Studies suggest that sensory stimulation helps to promote development in these children. The bear in-teracts with the child, reinforcing cause-effect rela-tionships between a button press and sensory stimu-lation.

SUMMARY OF IMPACT Most existing sensory stimulation activity centers are costly, only stimulate up to three senses, and are housed in simple plastic boxes. This activity center is housed in a stuffed bear and stimulates visual, audi-tory, olfactory, and tactile senses. The bear is visually appealing and fun for children of varying motor skills. It allows children to enjoy themselves while learning cause-effect relationships under the supervi-sion of a therapist.

Therapists who use the SSAC praise its benefits:

“The Pooh is so colorful and friendly that all of my children want to keep him for their own.”

“The Pooh helps the most with our physi-cally and visually impaired children. These children are not given the normal access to exploratory play that physically normal chil-dren do. Because of that, they are unable to learn independently as other kids do. We use Pooh to stimulate the senses of smell, sight, sound, and touch.”

“This is a much-needed toy. It will definitely be very useful to our therapy of these chil-

dren. Currently, similar products make the

kids easily bored. This toy not only keeps their attention, but is also very cuddly and fun to play with.”

TECHNICAL DESCRIPTION The active components of the device are housed in a stuffed bear. Two “C” batteries connected in series power the SSAC. A control panel on the bear provides the user interface for activation of the stimulation ac-tivities.

Activation of the functions is through momentary contact, normally-open push-button switches mounted on the control panel. The buttons have dif-ferent colors and shapes. Adjacent to each button is a picture and a light emitting diode (LED) with the same color scheme as the button. Each of the four but-tons, four lights, and four pictures is associated with a stimulation activity: releasing scented air, blowing air, vibrating the arm, and playing music. The picture located next to each button represents the activity powered when the button is pressed. When a button

Figure 6.1. A Child Using the Sensory Stimulation Activity Center.

Chapter 6: Duke University 79

is pressed and held the adjacent LED illuminates and the function is activated. When the button is released the function stops immediately.

Each button is connected to the power supply via the main power switch (see Figure 6.2). In parallel with each button is a 1/8” jack for an external switch. This allows either the control panel button or the ex-ternal switch to activate each function. In series with each button are the corresponding LED and a current limiting resistor. The components for the stimulation

activity functions are activated in parallel to the LED circuits.

The control panel is made of plastic reinforced by ¼” acrylic sheets. Items on the front face of the panel are mounted onto the plastic control panel and on the acrylic sheet reinforcement. All circuitry is housed within the control panel box. Circuit components are soldered onto a perforated circuit board.

SMELLISOLATION

UNIT

FAN 25.1

150LED

MELODY

150LED

MOTOR 1

LED150

150LED

FAN 1BLOWING AIR

VIBRATION

MUSIC

SMELL

(external jack)

(external jack)

(external jack)

(external jack)

1.5V

1.5 V

MainOn/OffSwitch

10uF .1uF

Figure 6.2. Circuit Diagram of Main Activities.


For the smell activity, a forked tube allows the pas-sage of air from the box to the outside of the mouth. A removable air freshener cartridge housed in an iso-lated chamber provides scented air. While the activ-ity is not on, a plastic flap blocks the smell from the tube leading to the mouth. When the button is pressed, a voltage pulse from a monostable multivi-brator (74HC221A) causes a motor to raise the flap, exposing the tube. A fan then blows the scented air out to the mouth. When the button is released, the multivibrator emits another pulse, the motor returns the flap to its closed position, and the fan turns off. This circuit is shown in Figure 6.3.

A box located inside the bear’s head contains the components for the smell and air blowing functions (see Figure 6.4). A centrifugal fan was built to maxi-

mize airflow through the bear’s mouth. A vibration unit was constructed using a motor spinning an off-center mass in order to produce a shaking effect when mounted in the bear’s arm. The unit is housed en-tirely in PVC plastic to increase robustness and safety.

The musical component comes from a commercial toy that plays a melody for a specific time when squeezed. The component was modified to play con-tinuously when powered by the button. A piezo speaker from the same toy is mounted near the sur-face of the bear’s fur.

The approximate cost of the Sensory Stimulation Ac-tivity Center was $340.

B1

CLR1B2A1

A2Rext2/Cext2

Cext2

Rext1/Cext1

Cext1

Vcc

2

3101

9

7

6

15

14

16

3.3uF

3.3uF

82K

82K

.1uF

MM74HC221A

390K

.1uF.1uF

2N39041 K

+3V

220K3.3uF

43K

+3V

Motor

11

413

12

5

8

CLR2

Q1Q1

Q2

Q2

GND

180

2N4403180

180

180

2N4401

2N4403

2N4401

Figure 6.3. Circuit Diagram for Control of Smell Isolation Unit.


Air freshener cartridge

Smell fan

Smell isolationmotor

Plastic flapCentrifuge fan

To mouth

TOP VIEW FRONT VIEW

Air freshener cartridge

Smell isolationchamber

Plastic Flap

To mouth

Figure 6.4. Diagram of Air Blowing and Smell Activities.


CHILD-FRIENDLY ACTIVITY TIMER Designers: Sean Breit, Stephanie Liu, Srinivasan Yegnasubramanian

Client Coordinator: Lenore Champion, Duke Hospital Supervising Professor: Dr. Laurence N. Bohs


Durham, NC 27708

INTRODUCTION The electronic Child-Friendly Activity Timer (CFAT) was constructed for use in pediatric therapy sessions. The CFAT features a small rabbit moving across a hill toward its burrow, and a digital display that shows the time remaining. When time expires, a beeper sounds and the rabbit returns to its starting location.

SUMMARY OF IMPACT Generally, for timed sessions, a therapist sets an elec-tronic kitchen timer that beeps when time is finished. However, most young children do not have a clear concept of time and cannot understand how much longer their practice sessions should continue. The CFAT was created to provide children with a visual and qualitative measure of time during therapy ses-sions.

The client is a two-year-old with a feeding disorder. Part of his prescribed therapy includes timed feeding sessions, where he is required to practice activities, such as holding his spoon and drinking from a cup for specific periods of time.

TECHNICAL DESCRIPTION The CFAT is a microprocessor-controlled device that contains both a numerical and physical display of the progression of time. The user programs the CFAT us-ing six pushbuttons. Three buttons set the time in in-crements of 30 seconds, one minute, and 10 minutes. The other three buttons start, stop, and clear the tim-ing process. The microprocessor reads from these six pushbuttons and controls the time displayed on a 4 ½ digit LCD 7 segment display as well as the movement of a toy rabbit, attached to an arm on the shaft of a ser-vomotor.

The CFAT consists of three sections: 1) input acquisi-tion; 2) time and display processing; and 3) numerical

and physical display (see Figure 6.6). The input ac-

quisition section contains the pushbutton hardware and the software required to process user input. The pushbuttons connect to the data lines on a Z-180 mi-croprocessor (Z2 Prototyping board, ZWorld, Inc, Davis, California) through a tri-state latch (74HCT373). The six-bit binary number representing the state of the pushbuttons is translated into an in-struction by the microprocessor. The program con-tains de-bouncing routines that prevent the micro-processor from reading unintentional input. Addi-tionally, the input software prevents the user from making logistical errors, such as accidentally clearing the time remaining during operation without first stopping the timer.

The time and display section controls a countdown timer and the servomotor. The countdown timer uses the real-time clock on the Z2 board to calculate the time remaining. The servomotor is controlled using an 8-bit binary number that increases at a constant rate determined by the input time. This binary num-ber is converted into an analog current using a digital to analog converter (DAC0832), and then converted to a voltage using a single-sided operational amplifier

Figure 6.5. The Child-Friendly Activity Timer.


circuit (LM358). This varying voltage is translated into a square wave with linearly varying pulse width using a voltage-controlled oscillator (CD4046). The square wave is connected to the control line of the servomotor. The servomotor moves through 30 steps over an angle of 120o.

The output section comprises a numeric display, a physical display and an audible buzzer. The time is displayed on a Varitronix 4½ digit LCD display. This display is controlled using 32 serial bits from a MM5452 controller chip. The serial clock and count data are generated by the microprocessor. The physi-cal display is a toy rabbit attached to the shaft of the servomotor. To conserve power, a transistor switch-ing circuit turns off the servomotor whenever it is not being moved. This feature dramatically reduces

power consumption since the servomotor only oper-ates for 30 seconds, regardless of the input time. Fi-nally, a small buzzer sounds when the time is fin-ished.

The CFAT uses four C batteries in series to provide a 6V DC supply, which powers the servomotor and the buzzer directly. The 6V DC is regulated to 5.2 volts to power the microprocessor and the other IC's.

The final cost of the Child Friendly Activity Timer was approximately $380.

U1

VI-509-DPDISPLAY

335

5

3476

361030291110

93137282524151413262721201918172223

110

1816

12

151413

11178765432403938373635343332313029282726

2326

backplane outbackplane in

COMCOM

outbits no. 1 - 32

+5V

Vcc20

47k19

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osc. in

U2

MM5452

serial clockserial datadata enable

212225

10

controloutput 1

14

17

18

4Q2Q3Q5Q1Q

+5V

20 Vcc

PiezoBuzzer

black

red

+6V

1D2D3D

4D5D

347

813

11 clock

U5

74LS374

U8 14

+5V

1 2

7

74LS04 B MJE3055T

B

C180

U9

U11Z180 Smartcore Z2

27151311975160 1 2 3 4 5 6 7

/CS4 17

10/CS6

3

GND

VBAT

/PPI

Vcc

+5V

1.40

2

4

14/CS2

1D2

+5V

S14.7k

3D2

+5V

S34.7k

4D2

+5V

S44.7k

5D2

+5V

S54.7k

6D2S64.7k

2D2

+5V

S24.7k

+5V

enable G7D8DVcc20

181117

10

1Q

2Q

4Q

5Q

6Q

2

5

9

12

15

7Q

19

16

8Q

U6

74LS373

output control1

U7

DAC0832

data in

7654

16151413

+5V

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CsXFERWR2GNDWR1

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10 17 18

10k

10kout1Vref

118

+5V

8

3

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U4 LM358

30k

10k

2k

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Vout = +2.5V(1+R2/R1)(13/256)

U3

CD4046BC

+5V

16VCOin

C1A

C1B10uF

9

6

7

12

11

R2

R1

3 8 14

100k1M

4VCOout white control

GND

black

red

+6V

IN914

C

E

B JE800180

outbitcontrol 1from displaylatch

1uF15

1N4739 470 12uF 22uF

+5V

+6VVout

U12

Voltage Regulator Circuit

Figure 6.6. Timer Schematic.


COMPUTER GAMES FOR LEARNING JOYSTICK CONTROL

Designers: Pinata Hungspreugs and Becky Poon Client Coordinator: Robbin Newton

Lenox Baker Children’s Hospital Supervising Professor: Dr. Laurence N. Bohs


Durham, NC 27708

INTRODUCTION Two joystick-controlled computer games, “Catch the Butterfly” and “Bump & Go”, have been developed to train children to use powered wheelchairs. Com-pared to other wheelchair trainers currently available, these games are more fun to play. They also provide feedback concerning the child’s progress to the thera-pist. The software can be shared to enable the child to practice at the hospital with the therapist, or at home under a parent’s supervision.

SUMMARY OF IMPACT Since most powered wheelchairs use joystick control, it is helpful if children learn to operate a joystick prior to trying a powered wheelchair. “Catch the Butterfly” and “Bump & Go” help improve joystick skills be-cause they are fun to play and motivate the child to improve performance. In addition, statistical data may be used to evaluate whether a child has difficulty stopping or moving in a certain direction.

TECHNICAL DESCRIPTION

The computer games are written in Visual Basic 5.0 for IBM compatible computers. These games require a Windows 95 operating system, 4 MB free hard drive space, and a sound card with a joystick port

“Catch the Butterfly” helps beginners and younger children become adjusted to using a joystick. In this game, the child manipulates, on the screen, an image of a boy holding a net. The object is to catch a butter-fly. To encourage the child, a reward screen using visual and audio stimuli is shown each time a butter-fly is caught. The game contains three levels of diffi-culty. In the first level, the butterfly remains station-

ary to allow the child to learn how to handle the joy-

stick. In the second level the butterfly flies around the screen. This allows the child to practice following an object and moving the joystick in different directions. The third level features a bee (see Figure 6.7) that the child must avoid while attempting to catch the butter-fly. If the boy is “stung” he is moved further away from the butterfly.

“Bump & Go” is a more challenging game that ac-quires statistical feedback on the progress of the child. There are four levels of increasing difficulty. Each level consists of a car that the player must move with the joystick to reach his or her “destination,” an im-age that appears in random positions on the screen. The player drives the car from the starting point in middle of the screen to the destination. Walls act as barriers between the car and the destination, except in the first level. With increasing levels, the number of walls increases and the size of the openings between them decreases. Though the images appear randomly, they are placed in specific areas of the screen. This al-

Figure 6.7. Screen for the Bump & Go Game.


lows the therapist to determine if the child is having trouble moving the joystick in a particular direction.

“Bump & Go” contains a stop sign function that re-cords the amount of time it takes for the child to stop moving. A timer also records how long it takes for the car to reach each destination. This information is saved in a file to allow the therapist to evaluate whether the child is having difficulty moving in a particular direction.

A scoring system is implemented in “Bump and Go” in order to motivate the child. The final score is de-termined according to the amount of time the child requires to reach the destination image and the num-ber of objects the child hits during the game.

Each object in these games is a represented by a bit-map image. Its position in the game field is given by the object’s x and y coordinates with respect to the upper-left corner of the field (0,0). Visual Basic 5.0 automatically calculates many properties of the object in the program including the height, width, and co-ordinates of the top, bottom, right, and left edges of the image.

To make the game more entertaining for the child, colorful animated images were used (e.g. the boy in “Catch the Butterfly” runs around the screen). This requires a series of images, each slightly different, which create the effect of movement when rapidly al-ternated (i.e. like a flipbook.) Joystick control is given to the characters using the program joystick.exe from Mabry Software (Stanwood, WA), which returns the x and y coordinates of the joystick. These values are used to position the image on the screen. When the joystick moves a certain distance in one direction the function Joystick1_Move is activated and moves the object (the car or the boy with the net) in the direction the joystick is pushed. The distance the image moves can be increased or decreased by changing the num-ber of pixels the image shifts when the function is read. The program also ensures that the image does not move off the screen.

The games must be able to identify collisions between two images on the screen. The functions Collided , Hi-tUpDown, HitLeftRight, and LtRtShort detect the colli-sion of two objects. Collided obtains the coordinates of the right, bottom corner of two bitmaps, which are then passed to the Windows API function called In-

tersectRect. This function will return 0 if the two im-ages do not overlap. If they do overlap, IntersectRect returns a 1. This invokes the reward screen that is controlled by the function Timer2. Collided is used in “Catch the Butterfly.”

To detect collisions between the car and walls or des-tinations in “Bump & Go,” the functions HitUpDown, HitLeftRight, and LtRtShort are used. In these func-tions, the coordinates of the car are compared to each object on the screen by a series of if–then statements to see if they are touching each other. If the car touches a block, the position of the car changes so it “bounces” back from the wall. If the car touches a destination point, Timer2 is invoked and the reward screen appears.

A function was written to record the time it takes for the child to move the car from the starting point to the final destination. When the car appears on the screen, the command Timer, which captures the time of day in seconds, is called and is saved as Start. Timer is then called when the child reaches the destination image and the time is saved as Finish. The difference between Finish and Start is used to determine the av-erage time required to reach each destination on the screen. This information is then written to a file specified by the therapist if he/she chooses to record the data.

Though the games are in good working condition and satisfy the original objectives, there are several com-ponents that could improve the project. Improve-ments could be made on the feedback information for the therapist and time analysis. One way that this could be done would be to consider the speed of the car. If the car is set to a higher speed, the car will reach the destination more quickly, and the average time might not be a good indicator of performance. It may be useful to implement a performance gauge function that averages speed and time. This could be coupled with an evaluation screen that would give suggestions to the therapist on what the child should work on and if he or she is ready to play at a more dif-ficult level.

The total cost of this project was $195, including the cost of the joystick and sound card for the PC.


AUTOMATIC FEEDER MODIFICATIONS AND WHEELCHAIR-TO-BED TRANSFER APPARATUS

Designers: Atif Haque & Kulbir S. Walha Client Coordinators: Robbin Newton and Tonya Hamm

Lenox Baker Children’s Hospital Supervising Professor: Dr. Laurence N. Bohs


Durham, NC 27708

INTRODUCTION An electric feeder was modified and a wheelchair-to-bed transfer apparatus was developed for a young man with cerebral palsy in order to increase his inde-pendence in everyday activities. A ceiling mounted transfer bar was created to allow the client to trans-port himself between his bed and wheelchair.

SUMMARY OF IMPACT The client is a 20-year-old man with cerebral palsy who uses a wheelchair. Because of his muscle control limitations, he previously had to be fed by his par-ents. The modifications made to the Winsford feeder now allow the client to feed himself.

His disability, along with injuries he suffered in a re-cent car accident, make it impossible for him to get into and out of his wheelchair from his bed without assistance. At the client’s suggestion, the transfer ap-paratus was built, allowing him to move himself be-tween his bed and wheelchair.

These items have reduced the client’s dependence on others in his daily life. He comments, “I enjoy the in-dependence (the feeder) gives me to be able to feed myself. Sometimes I get a little messy but that’s ok. I'm sure my mom enjoys getting a break from feeding me everything that I eat. I continue to enjoy the transfer bar in my bedroom. It is a big help when I get in and out of bed. These projects that you developed for me have been very beneficial.”

TECHNICAL DESCRIPTION A damaged Winsford feeder (Klemco Engineering, Plumsteadville, PA) was donated and repaired to make it operable. A new clamp was designed and

constructed from aluminum block to allow the Buddy Bar to attach to the client’s new wheelchair, which was purchased after his automobile accident. The Buddy Bar allows table-mounted devices, such as a computer, to attach to the wheelchair.

To accommodate the feeder, a Plexiglas plate was de-signed to fit tightly into the feeder’s base. A key mechanism was designed from aluminum to slide and lock into place on the Buddy Bar lock plate. In order to increase stability, a Velcro strap wraps around the arms of the wheelchair and connect at both ends to the base of the feeder.

The client and his father noted other possible im-provements that might be made to the feeder. The me-chanical arm lifted the food in an arc that extended past the plate. Hence, any spilled food fell onto the client’s lap. To fix this shortcoming, the feeder was modified as follows. To control the topmost point in the feeder's arc, the pentagonal cam of the feeder was positioned so that the slanted side was flush to the feeder when the arm was in its apex. To keep the arm angle suitable for picking up food, an adjustable stop was constructed out of aluminum and attached to the feeder's surface below the arm. The cams were also altered so the lifter stopped at the angle the client de-sired. The spring mounted in the utensil holder was re-placed with a rigid, stainless steel tube to improve the client’s ability to eat without spilling food. In order to increase the amount of food that the lifter would carry during each cycle, a modified utensil was made. The initial utensil was a spoon; however, it did not lay flush against the plate when the lifter arm was in the down position. The spoon was replaced with a spork (a spoon with prongs on its end). The spork was


used because it has a much flatter tip than any avail-able spoon. The spork was flattened and its prongs were rounded. The modified utensil consistently picks up almost twice the amount of food per cycle as the original spoon. The transfer apparatus (Figure 6.8) uses an arm consisting of a rod within a tube, both constructed of stainless steel. The inner rod has tapped holes at 2” intervals, allowing the height of the handle to be adjusted by aligning it with screws placed through holes in the outer tube. The handle is constructed from 1" diameter stainless-steel rod to provide an adequate grip diameter for Ray. The top of the pipe is connected to a universal joint from McMaster-Carr Supply Company (Atlanta, GA). The

original joint only provided a 25o angle of vertical mo-tion and very limited rotation. The vertical angle was increased to approximately 80o by grinding the joint's surface. 360o rotation was enabled by using a thrust bearing from Dixie Bearing Co. (Durham, NC). The transfer apparatus was mounted to the ceiling of the client’s bedroom using a custom plate constructed of 1 x 4 x 20” aluminum block, which distributes the load across two ceiling studs above the bed. Holes in the plate allow the transfer apparatus to be mounted in three locations relative to two ceiling studs. The estimated cost of the feeder modifications was $185. The complete transfer apparatus cost approximately $170.

Figure 6.8. Bed-to-Wheelchair Transfer Apparatus.


POOL CHAIR Designers: Julianne Hartzell and Jennifer Peters

Client Coordinators: Beth Hildebrand and Cherie Rosemond Carol Woods Retirement Community

Supervising Professor: Dr. Laurence N. Bohs Department of Biomedical Engineering

Duke University Durham, NC 27708

INTRODUCTION A wheelchair was designed and constructed to en-able therapists to transport patients into and out of a pool.

SUMMARY OF IMPACT Previously, therapists had difficulty moving elderly patients into and out of a pool for therapy sessions. The wheelchair previously in use had small wheels that made movement on the rubber matting surround-ing the pool difficult or impossible, requiring two therapists to lift patients seated in the chair.

The new chair, with its larger wheels, can be maneu-vered easily by one person and is safer than the pre-vious chair. Lifting is not required. The braking mechanism allows the chair to be fixed in position once in the water, and is easily operated from the back of the chair by the therapist. Finally, the wheel-chair is equipped with a dark green webbed seat in order to improve its visibility in the pool water.

This chair makes transport into and out of the pool safer and more enjoyable for both patient and thera-pist. A physical therapist who has used the pool chair with patients says, "I feel safe with residents when I use the chair. It maneuvers easily over vari-ous surfaces and I can push it up the ramp by myself. Residents like the seat belt feature and the chair stays put at the bottom of the ramp… all positive changes over any off the shelf chair we could find."

TECHNICAL DESCRIPTION The pool chair (see Figure 6.9) was designed to assist a person weighing up to 250 pounds into and out of a pool. It was constructed for easy mobility and control around a pool and also provides a simple and effec-tive safety latch.

The frame of the chair is made of 1 ¼ inch diameter, schedule 40 PVC pipe (see Figure 6.10). 3/8-inch holes are drilled in the bottom pipes to allow water to enter the chair once in the pool and drain the chair when exiting the pool. This prevents the chair from floating and allows the patients to easily get back into it after therapy. 1/4-inch holes are drilled in the top pipes to allow air within the chair to escape as it fills with water. Front safety bars with ring connectors are attached to one side of the chair. The bars pivot hori-

Figure 6.9. The Pool Chair.


zontally from this side and attach with spring pins to the other side of the chair. The front wheels are four-inch diameter plastic casters. The rear wheels are 1/8-inch diameter plastic wheels with mold-on rub-ber tires and Delrin bearings. They are attached to the chair by a ¾-inch nylon axle that is reinforced by four nylon sheaths over the section of the axle between the wheels. The wheels are held onto the axle by small outer caps bolted to the axle. The seat and backrest are made of vinyl coated polyester fabric. The seat is cushioned and has a seatbelt. A curved PVC bar sup-ports the seat.

The brakes of the chair have two handles, one for each wheel. Each handle is made of a length of PVC

tubing. The handles are attached to nylon hollow tubing by a pivot. The entire brake system is attached to the chair by a ring of PVC glued to the frame and held in place by two screws. When the handles are turned, the pivot drives the nylon tube into the wheel well. The wheel is held stationary when the nylon rod comes into contact with the spokes of the wheel. This contact prevents any further motion of the wheel. The end of the hollow nylon tube is sectioned so that it will fit inside the wheel well.

The total cost of the pool chair was approximately $280.

Top

Side

Front

Figure 6.10. PVC Frame of the Pool Chair.

91

CHAPTER 7 MANHATTAN COLLEGE

School of Engineering Mechanical Engineering Department

Riverdale, NY 10471


Daniel W. Haines (718) 862-7145 [email protected]


AUTOMATED DIE ROLLING DEVICE Designers: Maribel Cruz, Stephan Rutgerson, Suzanne Wright

Client Coordinators: Laura Meza, Dan Schipf Brandywine Nursing Home, Briarcliff Manor, NY

Supervising Professor: Dr. Zella Kahn-Jetter Mechanical Engineering Department

Manhattan College Riverdale, NY 10471

INTRODUCTION A device was designed so that residents of a nursing home could reliably roll dice with the push of a but-ton or activation by breath control.

SUMMARY OF IMPACT The Automatic Die Roller is now in the recreation room of the nursing home where the residents and caregivers find it rewarding to use.

TECHNICAL DESCRIPTION The Automatic Die Roller is contained in a square polystyrene box with a sloping roof. The lid is hinged to allow access to the interior.

Figure 7.2 shows the two dice resting on the platform that flips the dice upward. The platform is activated by a push-type solenoid. A side cut-away view of the device is shown in Figure 7.3.

The cost of the Automatic Die Roller is $147.73.

Figure 7.1. Automated Die Rolling Device. Figure 7.2. Close-up Showing the Two Dice Resting on the Platform.

Chapter 7: Manhattan College 93

120V PUSHBUTTONSWITCH

MOMENTARY

SAFETYCONTACT

SWITCH

SECURING LATCH

CLEAR POLYCARBONATESHEET (1/4 INCH THICK)

GAME PIECECOMPARTMENT

HINGES (2X)

PLATFORM

RUBBER FEET

SOLENOID HOUSING

SOLENOID MOUNTINGBRACKET

SOLENOID(120V AC)

POTENTIOMETER(120V AC)

WIRE NUT

STRAIN RELIEFAND 120VPOWER CORD

ADAPTER PLUGS FOR CUSTOM SWITCHES

Figure 7.3. Side Cut-Away View of the Automated Die-Rolling Device.


VENTILATING SYSTEM FOR A NURSING HOME GREENHOUSE

Designers: Michael Donaghue, Jennifer Grzan, Stephen Grzic Client Coordinators: Susan Holmes, Dan Schipf

Brandywine Nursing Home, Briarcliff Manor, NY Supervising Professor: Dr. Zella Kahn-Jetter

Mechanical Engineering Department Manhattan College

Riverdale, NY 10471

INTRODUCTION During their initial visit to a nursing facility, the de-signers were shown the greenhouse where many products built by previous Manhattan College stu-dents are in use. They noticed that the ventilation system in the greenhouse was noisy and the room was very warm. A project to improve the situation was defined.

SUMMARY OF IMPACT The existing exhaust system was evaluated. It was determined that adding new components and retrofit-ting others would result in a quieter, more efficient exhaust fan. The greenhouse is now much more pleasant with the new equipment in place.

TECHNICAL DESCRIPTION The new exhaust system consists of a motorized damper intake and a fan with an exhaust louver. Fig-ure 7.4 shows the position of these elements in a plan view of the walls of the 15 X 21 ft rectangular green-house room.

A Dayton 4-wing aluminum blade Venturi fan was selected for the fan element. The fan is powered by a 1/4 HP electric motor. It has a 10-inch propeller di-ameter and is encased in a 12-inch frame. At 1140 rpm the fan draws air at a rate of 945 cubic feet per

minute. This installed fan is shown from the interior of the room in Figure 7.5.

To create negative pressure, a 23 X 23-inch motorized damper was selected. The damper is wired so that it opens automatically whenever the fan on the other side of the room is turned on. The damper incorpo-rates a bug screen. Figure 7.6 shows the damper in the closed position behind the three designers.

The cost of the Greenhouse Exhaust System is $359.25.

21 feet

Electrical Wiring

Fan andExhaustLouver

MotorizedIntake

Damper

Figure 7.4. A Ventilating System for the Nursing Home Greenhouse.


Figure 7.5. Installed Fan Shown From Interior.

Figure 7.6 Designers and Device with Damper in Closed Position.


MODIFICATIONS AND ENHANCEMENTS TO A CONSOLE TV STAND

Designers: Alper Basoglu, Leon Fendley, Christopher Sheridan Client Coordinators: Laura Meza, Dan Schipf



Riverdale, NY 10471

INTRODUCTION A nursing home’s large-screen television required a more stable and versatile base.

SUMMARY OF IMPACT The residents and staff now have a television system that can be safely raised and moved about the floor more easily. This has eased burdens on the staff.

TECHNICAL DESCRIPTION Figure 7.7 shows two of the three designers with their product. The base is a trapezoidal box made of wood and covered with carpeting. Wheels on the base make horizontal movement easy. Two sets of safety straps

prevent the television set from tipping.

The cost of the materials for this project was less than $250.

Figure 7.7. Portable TV Stand.


ENHANCED ELECTRONIC TV CONTROL SYSTEM

Designers: Eric Glatzl, Stephen Lebron, Gregory Pascal Client Coordinators: Laura Meza, Dan Schipf



Riverdale, NY 10471

INTRODUCTION A patient with quadriplegia has had difficulty operat-ing a conventional remote control device for the tele-vision set in his room. He requested a device mounted to his bed rail that would enable him to op-erate the TV more easily.

SUMMARY OF IMPACT

The designers developed a working device with which the patient is pleased.

TECHNICAL DESCRIPTION The designers determined that a box with eight large buttons could serve the needs of this patient, pro-vided that the device performed the following func-tions: Power on/off, Channel up/down, Volume up/down, Television toggle switch, Cable box toggle switch, and Channel recall. Figures 7.8 and 7.9 show the control box with the buttons.

The cost of the Easy Touch Remote Control is $492.93.

Fig. 7.8. Top View of the Easy Touch Remote Control. Fig. 7.9. Side View of the Easy Touch Remote Control.


A TABLE-SIZE ROULETTE WHEEL Designers: Anthony Ferrara, Timothy Kim, Man Phan

Client Coordinator: Dan Schipf Brandywine Nursing Home, Briarcliff Manor, NY



INTRODUCTION During a visit to a nursing home, the designers ob-served that residents needed more varied recreation. Designers from Manhattan College had previously constructed a wheel of fortune for the residents. After consulting with the client coordinator, these design-ers decided that a roulette wheel would be well re-ceived.

SUMMARY OF IMPACT Although it was initially too large for the entrance, the roulette wheel was subsequently modified. The residents are pleased with the device.

TECHNICAL DESCRIPTION The design includes two tables, one for the numbers, and the other for the roulette wheel. The heights were set so that residents in wheelchairs could fit beneath them. Figure 7.9 shows the first table.

Figure 7.10 shows the table in which the wheel is mounted. The walls were set high to prevent the ball from leaving the table when in operation. A motor, connected by a belt and pulleys to the spindle be-neath the table, spins the wheel. Rotation of the wheel is initiated by a standard switch, button switch or breath control switch. The table is covered with Plexiglas to prevent the ball from escaping. A contact switch prevents the motor from operating unless the cover is in place.

Figure 7.11 shows the motor assembly.

The cost of the Roulette Wheel is $354.66.

Figure 7.9. Roulette Wheel.

Figure 7.10. Table in which Wheel is Mounted.


Figure 7.11. Motor Assembly.


A PNEUMATIC TV CONTROL SYSTEM Designers: Michael Christopher, Scott Sharp, Alexander Miranda

Client Coordinators: Laura Meza, Dan Schipf Brandywine Nursing Home, Briarcliff Manor, NY



INTRODUCTION The designers modified a TV remote control device for use by people with physical disabilities. They chose to apply pneumatic technology to develop a device that could be easily controlled by breath activation.

SUMMARY OF IMPACT The pneumatic TV remote control device operates well and reliably.

TECHNICAL DESCRIPTION Figure 1 shows the pneumatic remote control. It con-sists of three tubes mounted on an adjustable arm and connected to pressure switches. It was determined by experiment that a pressure switch setting of 3” of wa-ter is adequate for both sip and puff operations. Each of the three tubes and switches control one of the fol-lowing functions: Power on/off, Channel up/down, or Volume up/down.

A schematic diagram of the Pneumatic Remote Con-trol is shown in Figure 7.13.

Figure 7.12. Pneumatic Remote Control.


HIGH HIGH

LOW LOW

HIGH

Power

Channel

Volume

User Huffand PuffInput

Pressure SwitchLow (typ. for 2)

Pressure SwitchHigh (typ. for 3)

Switch BoxApprox. 4" x 7"

Standard 9-PinConnector

Figure 7.13. Schematic Diagram of the Pneumatic Remote Control.

103

CHAPTER 8 MISSISSIPPI STATE UNIVERSITY

T.K. Martin Center for Technology and Disability P.O. Box 9736

Mississippi State, MS 39762


Gary M. McFadyen (601) 325-1028 [email protected]


TRAIL READY UTILITY VEHICLE FOR PEOPLE WITH PHYSICAL DISABILITIES

Designers: Jennifer Long, Summer Martin Client Coordinators: Kris Geroux,

Supervising Professors: Dr. Timothy N. Burcham Department of Agricultural & Biological Engineering

Mississippi State University Mississippi State, MS 39759

INTRODUCTION The modern All-Terrain Vehicle (ATV) has increased the number of individuals participating in outdoor recreational riding. The ATV is a mainstay for hunt-ers and recreational riders because of its ability to traverse rough, narrow trails. Unfortunately, many individuals with disabilities have limited access to remote areas due to transportation limitations. Some wheelchairs have limited mobility when operated on non-firm surfaces, while others are too heavy and lack the necessary energy reserve to traverse rough trail conditions. To facilitate safe deep-woods access for handicapped individuals, the Trail-Ready Utility Vehicle (TRUV), Figure 8.1, was designed and con-structed according to the width of a standard ATV, thus allowing access on narrow trails.

SUMMARY OF IMPACT Ease of transportation to and from various hunting sites is a principal concern for hunters with disabili-ties. The Physically Challenged Bowhunters of Amer-ica organization reports that prior to the opening of the first disabled-only hunting tract in the State of Virginia, handicapped hunters had to be pushed through miles of wooded trails. The special features of the Trail-Ready Utility Vehicle allow individuals with disabilities to enjoy the outdoors.

TECHNICAL DESCRIPTION A review of present methods of transporting indi-viduals with disabilities to remote wilderness loca-tions, an evaluation of narrow rough access trails, and an examination of the limitations of disabled in-dividuals yielded the objectives for the TRUV. The TRUV is to be safe, low-cost, lightweight, ATV-towable, capable of traveling narrow trails, and tai-

lored to the transportation needs of the individual with disabilities.

The main frame, side supports and side ramp of the TRUV are fabricated from 2-inch and 1-inch square steel tubing. Two ATV tires are positioned at the rear and mounted on rubber torsion axles. This provides optimum floor space, minimum width and weight, ease in entrance and exit, and a low center of gravity. The main frame is constructed of 2-inch square steel tubing with a 1/8-inch wall. This material is also used in the tongue and in the frame supporting the axles. The remaining steel members are 1-inch square tubing with a 1/12-inch wall. These members in-clude staggered ladder bracing in the main frame, ver-tical side supports, top rail and the ramp framing, and bracing. The original center X-brace in the main frame was replaced with two longitudinal members positioned according to the distance between wheel-chair tires. These two members are connected with additional sections of 1-inch square tubing.

With tires in the rear, stiffness of the 500-pound ca-pacity axle system was tested. For load testing, an electric wheelchair was obtained from the T.K. Martin Center at Mississippi State University. With the axles in the rear, the front region near the tongue experi-ences the most deflection. Unloaded, the front, left corner of the floor frame is positioned 12 inches above the ground. With the new axles hitched to the ATV, deflection was noted with zero load, with a wheel-chair centered on the frame floor, and with the wheel-chair and a 190-pound person standing at the left, front corner. During motion, the vehicle rides com-fortably and adjusts well to challenging ground sur-

Chapter 8: Mississippi State University 105

faces at the low speed of 15 mph without causing the ATV to become off-balance.

The ramp/door of the TRUV is 64 inches x 47 inches. This provides ease in entering and exiting the TRUV. A 32-inch panel folds down after the innermost panel is pulled up to the side. For additional accessibility or maintenance, the ramp may be removed at anytime. Figure 8.2 shows the frame of the ramp without the top surface.

Two steel plates, mounted behind the box frame, pro-vide points of attachment for wheelchair tie-downs.

The nylon straps, manufactured by Welch Hydraulix Company, are locked into the steel plates.

The TRUV satisfies all performance objectives. The TRUV is 130 inches long, 45 in wide, and stands 46 inches tall. With the addition of the roll cage, side panels, jack, steel fenders, and camouflage covering, the TRUV will be an even more valuable tool for the disabled hunter.

The total construction cost of the TRUV is $1,253.90.

Figure 8.1. Trail Ready Utility Vehicle (TRUV).

Figure 8.2. TRUV Ramp.


ROLLER WALKER WITH SPRING-ACTIVATED BRAKING SYSTEM FOR A PATIENT WITH

CEREBRAL PALSY Designers: Angela Myers and Darby Shook

Supervising Professors: Dr. Gary McFadyen, Dr. David Smith, Dr. Joel Bumgardner, Dr. Philip Bridges, and Mr. Rusty McCulley

Department of Biological Engineering Mississippi State University Mississippi State, MS 39761

INTRODUCTION A specialized roller walker was designed for a client with cerebral palsy (Figure 8.4). The individual has more involvement of the right side, causing him to di-rect most of his weight to the left side of his body. The individual possesses only gross motor skills, but is active and capable of maneuvering a rolling walker. The frame had to be designed to the patient’s height, stance width, and stance depth.

SUMMARY OF IMPACT Individuals with physical conditions affecting their ability to perform the routine tasks of everyday life of-ten use ambulatory assistive devices. Cerebral palsy is an example of a disorder that causes reduced mus-cle performance, which may require the use of an am-bulatory assistive device. Walkers are one type of as-sistive device used to add gait support by providing a wide base stance and improving stability to anterior and lateral portions of the body. Although walkers are effective, not all individuals with disabilities are able to use standard walkers. Rolling walkers may be more efficient compared to the standard walker for people with limited upper body strength.

TECHNICAL DESCRIPTION

The material used had to be capable of withstanding repeated applications of concentrated force. The wheels had to be able to adapt to common surface frictions, overcome floor obstacles, and withstand typical weather conditions. In addition, the two rear wheels had to be able to withstand the pressure of an applied brake pad. The brake system had to be easy to engage with small amounts of force. Finally, it was

important that the brake stop the rolling wheel effec-tively without causing damage to the mechanism.

The walker has three main components: the frame, the wheels, and the braking system. An arm piece and a seat were added to the frame for comfort. The frame is

Figure 8.3. Roller Walker.


a solid rectangular structure consisting of 1'' ASTM A36 structural steel with welded joints. The walker stands 31'' high, 21'' wide, and 22'' deep (Figure 8.3). On the right hand bar is an arm support located 3'' from the front of the structure. An adjustable seat suspended from the left side of the walker can be re-tracted across the walker.

The front wheels are made of a hard synthetic rubber with a diameter of 5'' and a tread width of 1.5''. The rear wheels have a diameter of 4'' and tread width of 1''. The wheels are made of neoprene rubber and were obtained from the Darcor Company in Ontario, Canada.

The braking mechanism is a push-down spring-activated system. A solid steel block with dimensions of 2.25'' x 1.25'' x .75'' was welded to the base of the frame. A spring located in a plane perpendicular to the brake pad allowed for the brake action. When a force is applied to the frame, the spring compresses and engages the brake.

The welded frame provides adequate support and the braking system operates effectively.

Figure 8.4. Braking Mechanism.


WHEELCHAIR SEAT WITH AIR ROTATION TO RELIEVE PRESSURE

Designer: Suzanne Hutchinson Coordinator: Dr. Smith

Mississippi State University Supervising Professor: Dr. Gary McFadyen

Department of Biological Engineering T. K. Martin Center for Rehabilitation

MSU, MS 39762

INTRODUCTION A wheelchair seat was designed to relieve and rotate pressure by alternating airflow through the seat. This system is portable and can be used by both electric and manual wheelchairs.

SUMMARY OF IMPACT Many wheelchair users remain seated in their chairs for an average of 14 hours a day. If users have no means of shifting their weight, occlusion of blood ves-sels can occur in high-level pressure areas of the sup-port surface. By automatic rotation of pressure points, this seat will prevent such occlusion of vessels from occurring, especially in the area of the ischial tuberosities.

TECHNICAL DESCRIPTION The system has two components, the seat cushion and a control box that straps on the back of the chair (Figure 8.5). The cushion contains rubber tubes that inflate and deflate in a set pattern for predetermined time cycles. The system is designed to support the user at alternating points on the seated area of con-tact, decreasing the inhibition of blood flow. A 12-volt 7-amp/hour, rechargeable battery powers the system. The cushion has a foam base to support the user, in case system failure occurs. Testing with a pressure mapping system demonstrated pressure re-lief and rotation.

The seat cushion control box is packaged in a water-proof bag, color-coordinated with the cushion in royal blue. The seat system was designed for average user specifications. The weight limit is 150 pounds, with a safety factor of 2. The seat was designed to be convenient and easy to operate. One power switch is

placed on the armrest of the wheelchair to control the system. Once power is on, the cushion is fully auto-matic. A timer that has two independent time settings controls rotation. The on time setting activates the pump and opens one of two solenoid valves. The two solenoid valves control airflow in two groups of tubes (Figure 8.6). When the off time setting begins, the pump is turned off and a latching relay switches the direction of airflow. When the on time setting begins again, the pump inflates a different set of tubes. The first inflated set of tubes gradually deflates through an exhaust port on the attached solenoid valve.

The cushion consists of a 2-inch foam base of me-dium-soft foam. Four groups of four tubes lay hori-zontally on the foam base. The rubber tubes each have a 1-inch diameter. The groups alternate in an odd/even pattern of inflation. There is foam support on all four sides of the cushion. This seat is then cov-ered in a replaceable waterproof covering. The final covering of the seat is made from 100% cotton, ma-

Figure 8.5 - Active Pressure Relief Cushion With Control Box.


chine washable, lightweight material. The material breathes, allowing for moisture evaporation. Velcro attaches the covering, thereby enabling removal for washing. Air tubes, 3/8 " Tygon tubing, connect the cushion to the control box on the back of the chair.

Inside the control box, the tubes are connected to 3-way, 2-position solenoid valves. The solenoid valves are connected to a latching relay that switches power flow between the two valves. This creates the alter-nating inflation pattern. The relay and pump are connected to a timer that has two independent time settings. When power is supplied, the on time begins and the pump and relay receive power. When the in-flation time is up, the timer switches to its off time cy-cle. Removal of power turns the pump off and causes

the relay to switch position. When off time is com-plete, on time begins again, and the pump creates air-flow through the other tube groups. The power switch on the armrest of the chair controls the system.

This system is fully automated and easy to operate. After a full day’s use, a power cord coming from the control box can be plugged into an ordinary power outlet to recharge the battery. Recharging should be done overnight.

The final cost of this project was $333.00. The T. K. Martin Center for Rehabilitation provided use of test-ing equipment at no cost.

Figure 8.6. - Air Tubes Imbedded in Cushion.

111

CHAPTER 9 NEW JERSEY INSTITUTE OF

TECHNOLOGY Department of Electrical and Computer Engineering

Newark, New Jersey 07102

Principle Investigator:

Stanley S. Reisman (201) 596 3527 [email protected]


PC INTERFACE ENVIRONMENTAL CONTROL UNIT

Designer: William Cham Client Coordinator: Susan Drastal, Kessler Institute for Rehabilitation, West Orange, New Jersey

Supervising Professor: Dr. Stanley Reisman Department of Electrical and Computer Engineering

New Jersey Institute of Technology Newark, New Jersey 07102

INTRODUCTION The purpose of this project was to develop a PC inter-face to activate an environmental control unit.

SUMMARY OF IMPACT This device allows the control of appliances, lights, etc. by means of the PC. Whatever means are used to control a PC can be used to control the environment. Since the power line is used for transmission, the con-trol PC can be placed anywhere in the home.

TECHNICAL DESCRIPTION The unit consists of two parts, a PC interface and X10 technology. The PC interfaces with the control unit by means of an RS 232 cable connected to a serial port of the computer. Codes from the PC are passed through the RS232 port to the microprocessor, where they are converted into X10 codes. These codes are then sent to an X10 transmitter that puts the codes on the power line, and are picked up by the appropriate receiver to control the corresponding device.

X10 technology entails a communications language that allows compatible products to talk to each other

via the existing 110-volt electrical wiring in the home. A Lynx 10 microprocessor is used to decode the sig-nals from the PC and send them to the X10 transmit-ter module.

The signaling sequence consists of 11 bits that in-clude a two-bit start sequence, a four-bit house code, and a 5 five-bit key code. A bit is represented by bursts of 120 KHz carrier superimposed on the 60 Hz AC power and is produced by gating the carrier for about 1 ms., synchronized with the zero crossings of the 60 Hz signal.

The X10 units are first addressed by sending the house code and unit code. This operation tells the units to expect a command. In this way, several units on the same house code can be addressed simultane-ously. Next, a command or series of commands is sent to the units.

The approximate cost for the prototype unit was $120. This includes the microprocessor and X10 modules.

Chapter 9: New Jersey Institute of Technology 113

SPEECH RECOGNITION FOR AN ENVIRONMENTAL CONTROL UNIT

Designer: Guhan Raghu Client Coordinator: Susan Drastal, Kessler Institute for Rehabilitation, West Orange, New Jersey


New Jersey Institute of Technology Newark, New Jersey 07102

INTRODUCTION This project investigated the use of speech recognition technology to control an environmental control unit. This unit allows for control of up to four devices.

SUMMARY OF IMPACT Speech recognition is an increasingly attractive choice for control of appliances, tools, toys and com-puters. Persons with disabilities can benefit greatly from being able to control their environment through voice commands. With this project, radio frequency (RF) technology allows control from a different room or from a different part of the room. The person with disabilities can therefore remain stationary and con-trol appliances, temperature, and lighting anywhere in his/her home.

TECHNICAL DESCRIPTION The system consists of three modules: a voice recogni-tion module, a logic circuit with RF transmit-ter/receiver, and four line carrier decoders. The voice recognition module recognizes spoken commands and relays the command to the logic circuit, which decodes the signal and provides a pulse to the trans-mitter. The transmitter in turn sends a signal to the receiver that activates a device, such as a door, lamp, or television. The hardware was chosen because of its ease of use and minimal expense.

The voice recognition chip used is the HM2007, which was trained to recognize four words. Once trained, a word is spoken into the microphone and a number 01, 02, 03, or 04 is displayed. The voice kit was purchased pre-assembled except for the outputs from the board that would then connect to the logic circuit.

The HM2007 voice kit has an accuracy of detection in the 60 to 70 percent range. Although this is not ac-ceptable for a commercial system, it is acceptable for this prototype system. The fact that the kit comes as-sembled and is inexpensive made it appropriate for this project, despite its reduced accuracy. One possi-ble reason for its poor performance is the quality of the microphone. Future work will investigate the use of a better microphone. The logic circuit consists of three sub-modules. The first sub-module receives a signal from the voice board and classifies it. The sec-ond sub-module takes the output of the first sub-module and provides a single one-second pulse. The third sub-module uses the one-second pulse to pro-vide an electronic contact closure for use on the RF transmitter. The contact closure simulates the push of a button on a remote control, thereby sending a signal to the RF receiver. Originally a microcontroller was to be used instead of the logic circuit. However, no tim-ing information was available from the voice board so that a microcontroller could not be synchronized with the voice board. The RF transmitter/receiver module is connected to the logic circuit. Once a signal pulse is received from the logic circuit, the transmitter (RC5000 PHR02 Home Automation Remote) relays the pulse to the receiver. The receiver (RC5000 PAT01 Home Automation) then sends a signal through the home’s 120-volt AC circuitry. A line carrier decoder (PAM01 AGC Appliance Module) decodes the signal. If that decoder is set to receive that particular signal, it will turn on the device to which it is attached. The approximate cost for the prototype unit was $245, in-cluding the voice recognition board. Future iterations of this project may be made less expensive if the voice board is custom made.


SPEECH RECOGNITION FOR ENVIRONMENTAL CONTROL OF A WHEELCHAIR

Designer: Michele Raff Client Coordinator: Susan Drastal, Kessler Institute for Rehabilitation, West Orange, New Jersey


New Jersey Institute of Technology Newark, New Jersey

INTRODUCTION This project is a continuation of the previous project (Speech Recognition for an Environmental Control Unit). The goal was to increase the command capa-bility of an environmental control unit to control not only the environment but also the wheelchair motion of an electric wheelchair by voice commands. To ac-complish this goal, the hardware and software of the previous project were expanded to allow up to 16 commands to be recognized (the previous project rec-ognized four commands). The device employs RF technology so that a person using a wheelchair can control the environment from a different room.

SUMMARY OF IMPACT People who use wheelchairs may have limited use of their hands or arms, leaving them unable to control wheelchair motion or environmental functions. Such patients whose speech functions are within normal limits can use speech recognition to perform control functions. A device that integrates wheelchair motion control and environmental control would be an asset to such individuals.

TECHNICAL DESCRIPTION This project is based on the design for the project pre-viously described. A voice recognition board is inter-faced to a logic circuit that decodes the voice com-mands and then controls a transmitter to send a sig-nal to an X10 transceiver, which is connected through

the power line to X10 receiver modules. For this pro-ject the HM2007 voice recognition board was used as well as the HK10A Super Remote Home Automation System, which includes a 6-in-1 IF/RF remote already interfaced with two X10 modules, one transceiver module and one lamp module.

In order to use voice recognition for wheelchair con-trol in addition to environmental control, a sequence of two or three commands is necessary to achieve the final result. For example, in order to turn on a light, the user would say, “lights, turn, on”. This multiple command sequence adds a great deal of complexity to the hardware and software.

The approximate cost for the prototype unit was $295, including the pre-assembled HM2007 voice recogni-tion board. Future iterations of this project would be less expensive if a custom designed voice board were used.

115

CHAPTER 10 NORTH CAROLINA STATE UNIVERSITY

College of Engineering College of Agriculture and Life Sciences

Biological and Agricultural Engineering Department D. S. Weaver Laboratories

Raleigh, North Carolina 27695-7625


Susan M. Blanchard (919) 515-6726 Roger P. Rohrbach (919) 525-6763


EVALUATION AND TREATMENT TABLE

Designers: Julie Crutchfield and Amanda Fody Client Coordinators: V. J. Tangella and Ellen Canavan

Tammy Lynn Center for Developmental Disabilities, Raleigh, North Carolina Supervising Professors: Dr. Susan M. Blanchard, Dr. Larry F. Stikeleather

Biological and Agricultural Engineering Department North Carolina State University

Raleigh, NC 27695-7625

INTRODUCTION When speech-language pathologists, occupational therapists, physical therapists, or psychologists work with children and young adults with severe disabili-ties, treatment and diagnostic activities often take place in the therapy room. In order to work effectively with children and young adults, therapists need a ta-ble with adequate space to perform varied activities. A table was designed to allow adequate space around and underneath to accommodate individuals in dif-ferent wheelchairs.

SUMMARY OF IMPACT The table permits more effective treatment and evalua-tion for individuals in wheelchairs, and accommo-dates diverse users.

TECHNICAL DESCRIPTION The tabletop (Figure 10.1) is made out of medium density fiberboard (MDF) covered by polyvinyl chlo-ride (PVC) laminate. MDF is formed by heating and pressure treating a wood flour and glue mixture. The board is not like particleboard because it has no air pockets or small holes within the material. It has the density of solid oak, which makes the material very sturdy as long as it is protected from the elements. The PVC covering provides protection.

The tabletop has dimensions of 45”x 37”x 1”. The edges are rounded to 0.4” with a router. The surface of the top has a rectangular area cut out four inches from the top of the ellipse. This holds the tilting workspace when it is completely collapsed and makes it flush with the table. The rectangle measures 18” x 12”. The flattened ellipse that has been re-moved from the front of the table is 22” x 9”. The el-lipse was flattened to create more room for the user. This also leaves 7.5 inches of tabletop to the left and

right of the user, decreasing the distance he or she would have to reach for something on the table.

Under the rectangular cutout is a solid red oak box, which houses the brackets that support the tilting workspace. The dimensions of the box are 20.25” x 13.875” x 2.25”, ample enough not to interfere with legroom. The bottom of the box has only six inches of oak extending from each sidewall. Wood does not cover the entire bottom of the box so that it is easier to clean. One end of each bracket is fastened to each six-inch strip on the bottom of the box. The other end is fastened to the tilting mechanism.

The tilting workspace is also MDF with a PVC lami-nate. It is 18”x 12” x 0.5”. The round is 0.2”, slightly less than the rounding of the tabletop, so it is flush with the surface of the table. The top center of the tilt has an indentation made by a router in the shape of the flush brass pull ring so the pull ring is flush with the workspace surface. The flush pull ring is used as a way to raise and lower the workspace without ac-tually having to hold onto it. This minimizes the number of pinch point areas on the table. The work-space is attached to the table with one piano hinge. The brackets are fastened to the back or underside of the workspace and support it in 14 different positions that range from 0 to 90 degrees.

The frame for the table is made from 2014-T6 (4.4% copper alloy) aluminum. The aluminum tubing is 1” x 1” x 0.25”. The frame is 34” on the short sides, 42” on the longest sides, and 11” to the left and right of the cut out. The frame is welded together at each of the four corners. A weld in each corner of the frame attaches the aluminum flange legs. The aluminum flange is made of the same alloy as the frame. Its di-mensions are 2” x 2” x 0.125”, and the hydraulic cyl-inders are attached to the flange with screws. One leg

Chapter 10: North Carolina State University 117

consists of a hydraulic cylinder attached to the 2” aluminum flange, which in turn is attached to the MDF.

Monarch Hydraulics, Inc manufactures the hydraulic cylinder unit. The hydraulic unit consists of four hy-draulic cylinders, tubing, and the pump house. The cylinders are attached to the pump house by the fluid-filled tubing. The tubing is held in place flush with the under section of the tabletop via ring slip ties screwed to the table. The pump housing is attached to the MDF on the underside of the table using a 0.25” aluminum plate, which has counter sunk screws.

The white, non-toxic, hydraulic fluid is pumped through the pump house, through the fluid lines, and into the cylinders when the manual lever is turned clockwise. After the fluid is pumped to the bottom of the cylinder, it causes an increase in pressure that lifts the tabletop off the ground against its own weight. To lower the table, the manual lever must be

turned in the counter clockwise direction. This re-leases the pressure, allows the fluid to return to the housing, and, in turn, allows the tabletop to lower to any desired position. Casters are attached to the bot-tom of the cylinders so the table can be moved from one place to another within the therapy room. Two of the casters have braking mechanisms for safety.

The final cost of the table was approximately $1500.

Figure 10.1. Evaluation and Treatment Table.


BICYCLE CART FOR A CHILD Designers: Laura Cruse, Jason Latta, Chad Myers

Client Coordinator: Beth Buch Tammy Lynn Center for Developmental Disabilities

Supervising Professors: Dr. Susan M. Blanchard, Dr. Roger P. Rohrbach Biological and Agricultural Engineering Department

North Carolina State University Raleigh, NC 27695-7625

INTRODUCTION A bicycle cart was designed for a child with devel-opmental disabilities (Figure 10.2).

SUMMARY OF IMPACT This project was designed for a family that enjoys ac-tive recreation. The family has been limited in what they can do together because of a daughter’s physical disabilities. She has limited control of the muscles in her neck and trunk region. She has movement in her arms and legs about but cannot protect herself from falling, so she must be strapped into any seat she uses. The cart enables the whole family to go on bicy-cle outings together.

TECHNICAL DESCRIPTION The bicycle cart was designed for a specific child but could be used for other children who have similar needs. The main design requirements for the cart were: 1) The frame should be sturdy and strong enough to support the child and additional supplies, such as medical equipment or food for a picnic; 2) The frame should be wide enough to prevent it from tip-ping over; 3) The seat should provide support for the child; 4) The seat should prevent the child from slid-ing out; 5) The seat should support feet and legs so that the child's legs do not dangle; 6) The seat should be adjustable as well as comfortable; 7) The clamp that attaches the carrier to the frame must be easy to attach and detach; and 8) The cart must fold quickly and easily to a size for easy transport.

The bicycle cart has four main components: the wheels, the frame, the side rails, and the attachment arm. The frame is square with rounded corners and lower supports. The wheels attach to the frame by way of a quick release mechanism that slides on and off of the aluminum wheel brackets located under the

frame. The frame is made of 6061 USA grade alumi-num tubing connected by welding pieces of solid aluminum round stock inside the tubing connection points. The side rails are attached near the corners of the frame. These rails are attached with bolts on plas-tic folding mechanisms. A horizontal roll bar is at-tached at the top of the side rails by bolts and has a plastic swivel for folding. On the front left underside of the cart is the attachment arm that clamps onto the bicycle frame near the wheel. The arm is attached to the cart by a pin that allows the arm to swing under the frame for transport and storage. The mechanism that attaches the arm to the bicycle is made of a ball joint and clamping device.

The frame is covered by eight-ounce coated cordura nylon that is sewn and bolted on. The seat is also made of eight-ounce coated cordura nylon, with ny-lon webbing for support and attachment. The web-bing runs under the bottom portion of the seat and at-taches to the cross members of the side rails. The webbing sewn to the roll bar also supports the back of the seat. On the seat is a pommel style harness made of the same webbing used in the seat. It is attached with a plastic backpack clamp.

The cart was analyzed for stress and deflection using simple beam point load calculations. The appropri-ate equations were selected from the Midwest Plan Service Structures and Environment Handbook, 11th ed. A safety factor of 1.43 was used. This safety fac-tor had a corresponding probability of failure of 1%. A yield strength of 37,000 psi was selected from the tables in the same handbook. The maximum allow-able stress was calculated to be 25,874.13 psi. The cart was originally designed to withstand a maxi-mum load of 100 lbs. However, it was found that the cart exceeded the maximum allowable stress at loads between 225 to 250 lb with deflections in the range of

Chapter 10: North Carolina State University 119

0.15 to 0.30 inches. The only deflection that exceeded this range occurred in the upper batten, where a de-flection of 0.81 inches was noted at a 175-lb load. The upper batten was designed to provide lateral stability for the side rails and was not intended to endure loads over 100 lb.

Tests of the cart were performed with a 215-lb man. The cart showed little deformation and handled well even in rough terrain.

The final cost of this bicycle cart was approximately $1000.

Figure 10.2. Bicycle Cart.

121

CHAPTER 11 NORTH DAKOTA STATE UNIVERSITY

Department of Electrical Engineering Fargo, North Dakota 58105


Daniel L. Ewert (701) 231-8049 [email protected]

Jacob S. Glower (701) 231-8068 [email protected] Val Tareski (701)-231-7615

[email protected]


VOICE RECOGNITION CLOCK Project Engineers: David Hagan, Jamie Metzger, Kim Cuong Tran

Client Coordinator: Marla Wagonman, Centennial Elementary School, Fargo, ND Supervising Professors: Dr. Daniel Ewert & Dr. Jacob Glower

Department of Electrical Engineering North Dakota State University Fargo, North Dakota 58105

INTRODUCTION As a part of a class project, a group of fourth grade students attempted to envision what common devices used today would look like twenty years from now. One of these ideas was an alarm clock that tells the time in response to a spoken request. The students realized that such a device could be built today, and further, this device would be useful to a person with visual impairment or blindness. The teacher for this class approached the project engineers and asked if such a device could be built for the fourth grade stu-dents.

For such a device to be useful to a person with visual impairment or blindness, specifications provided by the students stated that the alarm clock be portable, have a display that is easy to read (for persons who are not blind but have visual impairment), have a voice output to tell time when activated, and be acti-vated through voice input.

SUMMARY OF IMPACT: The finished clock was delivered to the students. In a class ceremony, the students presented the talking alarm clock to a student with blindness, who contin-ues to use the device. The collaboration between the elementary students and the project engineers re-sulted in a device that allows a person with visual impairment or blindness to more easily tell the time, a group of elementary students observing and becom-ing involved with the design process, and the shar-ing of a joy for engineering among the young students and the project engineers.

TECHNICAL DESCRIPTION The design of the Voice Recognition Clock centered around three components: the voice input, the talking alarm clock, and interface circuitry.

A HM2007 Voice Recognition Processor Demo Board was selected for the voice input. This board is an evaluation board for the Hualon HM2007 Voice Rec-ognition Chip, capable of recording and recognizing up to 16 different words or phrases.

The evaluation board comes fully assembled and ready to use. To program a word or phrase, the op-erator types the word that he/she is going to say (from 00 to 16) on a keypad, followed by a pound key, and speaks into a microphone. When that word is spoken again and recognized, the number (from 00 to 16) is displayed on a two-digit LED display and sent to an eight-pin BCD output port.

Arbitrarily, word #08 was selected as the word that will trigger the talking alarm clock. The buffer cir-cuitry looks for the spoken word #08. A flash of an LED on the evaluation board signifies that a word was detected, and then the number 08 appears on the LED display. Once detected, a one-shot closes an electronic switch.

A Radio Shack Alarm Clock Radio (Cat. No. 63-912) was used for the talking alarm clock. This alarm

Figure 11.1. Students During Construction. (From an Article in the Fargo Forum).

Chapter 11: North Dakota State University 123

clock has a large 1" LED display and a speech chip built in. When the operator presses a "Voice" button, a momentary switch is closed and the alarm clock "speaks" the present time. By shorting this switch with the output of the buffer circuitry, the operator is able to trigger the alarm clock by speaking whatever phrase was previously recorded in position #08 in the voice recognition board.

The final design of the clock is housed in a 14cm x 19cm x 16cm Plexiglas enclosure and weighs about 1kg. The keypad for programming the voice recogni-

tion board and the speaker are on the top of the clock. In addition, three buttons for setting the time, the alarm, and resetting the voice recognition board are placed.

The total cost was approximately $250.

+5

1k

3.9k

R

Q

TR

gnd Vcc

DIS

1k

+5

7404

Clock Button

S

CLK

D

R

Q

7474LM 311

10k22uF

7404

4th Bitfrom VRB(Word #08recognixed

LED Signal(from VRB)

Figure 11.2. Buffer Circuitry Between Voice Recognition Board and Talking Alarm Clock.


ALARM CLOCK FOR INDIVIDUALS WITH HEARING IMPAIRMENT

Project Engineers: Pierre Bartoo, John Hagan, Anishman Tripathy, Brian Volk Supervising Professors: Dr. Daniel Ewert and Dr. Jacob Glower

Department of Electrical Engineering North Dakota State University

North Dakota State University Fargo, North Dakota 58105

INTRODUCTION Individuals with hearing impairment have a difficult time finding an alarm clock that is capable of reliably awakening them in the morning. An alarm clock that shakes the bed of the owner was designed to provide a reliable and pleasant way for individuals with hearing impairment to awaken.

TECHNICAL DESCRIPTION The Alarm Clock for the Individuals with Hearing Impairment consists of four main components: an alarm clock, a radio transmitter, a radio receiver, and an “alarm.”

The clock module is contained on a pre-made board containing the clock chip, display LEDs, and the cir-cuitry, requiring only a 9V power supply to operate. A 9V wall transformer provides power to the clock module as well as to the speaker and radio transmit-ter.

When the alarm goes off, a +5V signal is sent to the radio transmitter and the speaker. The transmitter uses AM modulation on top of a 1 MHz carrier to transmit the alarm to the receiver.

Two oscillators are used in the transmitter. One is used for the carrier signal and the other is used for the modulated "ON" signal. A 20MHz programmable chip oscillator produces the modulated signal. Its fre-quency can be divided 256 times to 78.125kHz. A 12-stage binary ripple counter then divides this signal to produce a 1.2kHz signal. This signal is used to modulate a 1 MHz carrier using the following circuit.

By using a 1 MHz carrier modulated at 1.2kHz, a portable AM radio was used to test the functionality of the transmitter and to estimate the range. A two- meter range was easily obtained with little or no use

of antenna. For a reliable signal, a six-meter range would be preferable. To obtain a greater range and to remove the harmonics from the 1 MHz square wave used for the carrier, an amplifier and LC tank were added to the final stage of the transmitter.

A seven-transistor superheterodyne receiver was used for the receiver of the modified alarm clock. This radio receiver came in a kit and receives radio fre-quencies from 540kHz to 1600kHz - the standard AM band. For this project, the receiver was tuned to 1 MHz.

The output of the receiver (tuned at 1 MHz) detects whether a 1.2 kHz signal is detected by the receiver or not. If a 1.2 kHz signal is detected on the 1 MHz car-rier, a 2n222 transistor switch turns on a pair of mo-tors. These motors have off-balance loads on their shafts, creating the "shaking" of the receiver box.

The final design consists of two units: the ra-dio/transmitter and the receiver/shaker. The ra-dio/transmitter is placed in a 20cm x 12cm x 5xm Plexiglas enclosure. This includes a 2cm LED dis-play for the time, buttons for setting the time and alarm, and a power jack for the 9V wall transformer. The receiver/shaker is placed in a 30cm x 10cm x 5cm Plexiglas enclosure and contains room for the motors, the receiver, and several batteries.

Field tests found that the receiver reliably detected the alarm at ranges of 3 meters without any external an-

RadioTransmitter

9:00 AM

Clock Module

1MHzReceiver

Alarm

Off-BalanceDC Motor

1MHz

Figure 11.3. Block Diagram for the Device.


tennas on the transmitter.

The total cost of the project was $182.

LM 741

LM 741

CLC 460

CLC 460

+5

20k

5.6k

DC Offset Adjust

1.8k

5.1k

5.1k

1.2 kHz

18k 5.5k

5.1k

1MHz Carrier

2.2k

1k

470pF 54uH

7.5k

5.1k

75k

Power AmplifierLC TankMixer

Figure 11.4. Circuit Diagram.

100

7.5k 0.1uF

560

2N222

68

+9

MotorwithOff-BalanceLoad

Signal fromAM Radio's Speaker



CAMERA FOR INDIVIDUALS WITH VISUAL IMPAIRMENT OR BLINDNESS

Project Engineers: Andy Freemeyer, Janna Harris, Tracey Tschepen, Stacy Barron Supervising Professor: Dr. Jacob Glower



INTRODUCTION: While a person with visual impairment may not be able to "see" with his/her eyes, he/she can still obtain information through the sense of touch. The goal of this project was to design a device that converts light intensity to a physical output, allowing the user to "feel" the image rather than see it.

SUMMARY OF IMPACT: The camera allows the light intensity of an object to be sensed by feeling the height of solenoids. Unfortu-nately, several difficulties were observed with the de-sign. First, the solenoids tend to chatter. This may be due to electromagnetic compatibility problems, ground loops in the design, or an exceedingly high gain in the buffer. Second, the solenoids do not pro-vide a firm surface. Weak springs were required so that the current demand of the solenoids was not ex-cessive. Weak springs, however, result in pixels that are too compliant when touched. Third, even with light springs this design required too much power. Before this design is expanded to a larger grid size, a better actuator must be incorporated.

TECHNICAL DESCRIPTION The light sensor consisted of a 5mm photovoltaic cell mounted in a handheld unit. Each sensor was placed in tubes 2 cm long to provide a 30-degree field of view for each sensor. Five of these sensors were placed in the handheld unit, as shown in Figure 11.7, allowing

the camera to observe a 30-degree x 90-degree region.

To allow the microcontroller to read the light level from the light sensors, a buffer circuit is used to am-plify the voltage produced from the sensors to a 0-5V signal. Two AD 626 instrumentation amplifiers pro-vide a gain of 100 for the sensor and remove any common-mode noise. A 0.47uF capacitor provides a low-pass filter with a corner at approximately 1 Hz to prevent aliasing at the A/D converter. A diode is then used to reduce the sensitivity of the sensor at high light levels.

For this device, the 6811 microcontroller acts as a five-channel voltage-to-pulse width modulation converter. The 0-5V signal from the buffer is read into the 6811 from Port E, an 8-bit A/D converter. Using real time interrupts, these inputs are read every 32.77ms. Each

Buffer 6811Microcontroller ActuatorLight Sensor

Power

Figure 11.6. Block Diagram of the Device.

Handheld Unit

PhotovoltaicLight SensorsImage

Figure 11.7. Sensors.

AD 626 AD 626

+5

1k

0.47uF

Ge Diode

PhotovoltaicCell

A/3

21

8 6

5

+

-32

1

8 6

5

+

-

+

-

Figure 11.8. Buffer Circuit.


time they are read, the value read from the A/D is copied to a buffer (Figure 11.8).

Five pulse-modulated signals proportional to the voltage read from the A/D converters are generated by the 6811 through the real time clock. Every timer overflow (time=00) causes an interrupt that sets the outputs from Port B high (the start of the PWM sig-nal). When the on-board timer exceeds the value in the buffer for a light sensor, the appropriate bit on Port B is cleared. This creates a 0-5V PWM signal with a duty cycle nearly 0% for a dark room and nearly 100% when the sensor is pointed at a white ob-ject in the room.

The actuators chosen for this project are five STA pull type solenoids from Lennex Corporation. These sole-noids require 24V to operate and provide a pull strength of approximately 0.3N. The iron shafts of these solenoids are connected by a spring to a rod above the solenoids. When no current is applied, the rod is fully extended. The 6811 can then control the height of these solenoids by adjusting the voltage ap-plied to the solenoid.

A 2n222 transistor serves as a power amplifier for the 6811 to drive the solenoid, as shown in Figure 11.9.

The cost was $502.

Height = Light Intensity

Top of Enclosure

Spring

Pull-TypeSolenoid

0% to 100%PWM Signal

+24V

Figure 11.9. Solenoid.

100

2N222

+24V

0-5V PWMSignal from

the 6811

Solenoid

Figure 11.10. Another Circuit for the Device.


EXERCISE ENHANCER Project Engineers: Jamie Hauser, Kasey Morlock, Jeremy Mattson, Don McAdoo

Client Coordinator: Jon Hinrichs, Hawley High School, Mawley, MN Supervising Professor: Dr. Jacob Glower



INTRODUCTION Exercise and conditioning are important for main-taining one's health. Exercise strengthens muscles, improves coordination, and may even improve one's mental state. Exercise is especially important for someone who is recovering from an accident, or for elementary school students with limited coordina-tion.

Unfortunately, while exercise is important, exercises are often inconvenient, requiring a physical therapist to ”encourage” and supervise, and expensive, as such programs are often not reimbursable by insur-ance. In addition, exercise programs may require individual attention - something a K-12 instructor is not able to provide when teaching a large class.

A device that is inexpensive, portable, computer con-trolled, and capable of monitoring one's exercises automatically, is a tool that could eliminate common concerns about exercise programs. Such a device would enable teachers to provide individual exercise plans for students with limited coordination, allow the students to work on their own, and to monitor their activity without taking time away from other students.

One type of exercise commonly used for conditioning and rehabilitation exercise requires the patient to hop back and forth as fast as he/she can for a set amount of time. Numbers are often painted on the floor, as shown in Figure 11.11, to facilitate the activity. A physical therapist or teacher then counts how many times the patient can do several different patterns (such as hopping from square 4 to 5 and back, 4 to 2 to 5 and repeat, etc.).

In this project, an instrumented floor connected to a PC was built. Design criteria were that the floor allow the therapist to prescribe the pattern to follow, allow

the therapist to determine the time of the test, have the total number of successful repetitions automatically counted and recorded on the PC, be portable, and be inexpensive.

SUMMARY OF IMPACT First, the Exercise Enhancer may allow instructors to better monitor the progress of students who are recov-ering from an injury or have limited coordination.

Second, the ability to better monitor the progress of students allows instructors to accurately assess the efficacy of different exercises.

Third, the Exercise Enhancer is completely auto-mated, so instructors may be able to work with more students at one time. The computer conducts tedious activities such as counting and recording the number of repetitions for each exercise.

This device was delivered to a high school for evalua-tion. Future improvements will make this device us-able by any physical therapist or teacher.

TECHNICAL DESCRIPTION The foot speed timer is a grid of nine squares that is set up on the floor. For this design, a 3.2m x 3.2m

1 2 3

65

987

4

Parallel Port

Computer

Figure 11.11. Grid.


square made of plywood was used for strength and cost effectiveness.

Each of the nine panels is made out of a separate 35cm square piece of plywood. Four doorstops are placed under each panel, raising them when no weight is applied. When a student stands on a panel, the doorstop compresses and a switch underneath the panel closes. In this way, a 3x3 keypad is created, allowing the instructor to monitor which square (if any) the student is standing on.

The nine switches in the floor panel are connected to the parallel port of a PC along with pull-up resistors as shown in Figure 11.12.

With this setup, the parallel port can be read using C++ for DOS. The readings for the student standing on each panel are summarized in Table 11.1. Note that by using the wiring shown in the previous figure, three pins should read high and three should read low at all times. This provides a error correction and allows the software to detect when the parallel port cable has not been connected to the platform.

Software to monitor the parallel port and detect these sequences was written in C++ for DOS. This software allows the operator to monitor the number of times the student completes an exercise as well as the time it takes to go between squares to 1/60th of a second.

The total cost for this device was $178.

Square Student is Stand-ing On

Data on Parallel Port

Pins 2/3/4/5/6/7

None 010101

1 100101

2 001101

3 000111

4 110001

5 011001

6 010011

7 110100

8 011100

9 010101

Table 11.1: Parallel Port Readings According to Panel.

31 2

4 5 6

987

+5

+5

+5

+5

+5

+5

Pin 2

Pin 4

Pin 6

Pin 25 (gnd)

All resistors 1k

Pin 7

Pin 5

Pin 3

Parallel Port



FORCE MEASUREMENT FOR PROSTHETICS Project Engineers: Scott Wandler, Randy Kahlstorf, Dan Lang, Bryan Smith Client Coordinator: Lisa Miller, St. Alexius Medical Center, Bismarck, ND

Supervising Professor: Dr. Jacob Glower Department of Electrical Engineering

North Dakota State University North Dakota State University Fargo, North Dakota 58105

INTRODUCTION: Physical therapists at a medical center requested a device to provide balance feedback to patients who use prosthetic legs. The device was to measure the weight a patient applies to his/her prosthetic limb, and display this weight to the patient.

It is hoped that, with biofeedback, patients will be able to "feel" how much weight they are applying to a prosthetic limb. This in turn may help accelerate the process of learning to walk with the prosthesis.

SUMMARY OF IMPACT This device was delivered to physical therapists at a medical center. Based upon their experience using this device, further refinements will be necessary.

TECHNICAL DESCRIPTION Since prosthetic limbs are relatively expensive and custom designed for each patient, it was not consid-ered feasible to place a force sensor on the limb itself. Instead, a device was sought that can be added to a shoe.

The Force Measurement for Prosthetics Device con-sists of two main components: a force sensor and a hand-held display. The force sensor selected was a pair of Air Nike running shoes. These shoes have an air pocket along the length of their soles. As the pa-tient places more weight on the shoe, the pressure in the air pocket increases. (Note: both Air Pippen bas-ketball shoes and Air Nike running shoes were used in this project. Air Pippen basketball shoes do not experience a significant change in air pressure when one stands in the shoe - almost as if the air pocket were decorative. The Air Nike running shoes proved to be much softer and more sensitive.)

To measure this air pressure, a hypodermic needle is inserted into the air pocket of the running shoe. This needle is glued to a piece of surgical tubing 1.5m long with a 100psi pressure sensor (Digikey part NPC-410) glued to the other end, creating a disposable needle/ pressure sensor unit. A second surgical needle is placed on a basketball pump for reinflating the shoes prior to use.

The output of the pressure sensor is amplified with a gain of 100 by an AMP04 instrumentation amplifier. This signal then drives a 10 segment LED bar display.

The LED bar display is controlled by a TSM-3914 chip. This chip has two reference resistances (Rlow and Rhigh) and Signal In voltage as its inputs. Rlow determines the voltage at which no LEDs are turned on. Rhigh determines the voltage where all ten LEDs are turned on. Intermediate voltages then activate a proportional number of lights.

Two potentiometers allow the operator to set the two control voltages. When the operator is not applying any weight to the show, the low set point is adjusted until no LEDs are on. When the operator places all of his/her weight on the shoe, the high set point is ad-justed until all LEDs are lit. From that point on, the LED display will show the approximate weight the patient is applying to that foot - from 0% to 100% of their weight.

The resulting design for this device costs $198 - 70% of which comes from the running shoes. By using off-the-shelf running shoes, this device should be usable for any patient with any shoe size. Further, since the air pocket can be reinflated (it leaks, however the pressure will remain for a day or two - long enough for a walk), the same pair of shoes can be used for a several patients. Finally, since the bar graph display


can be calibrated for each user, this device should be usable for both children and adults.

NPC-410

gnd

Out+

IN+

Out-

IN- AMP04

gnd gnd

+5

1k

Ref Adjust

Ref Out

Mode

Rhigh

Signal In

Rlow

V+

gnd

NC

Vled

+5V

-9V

+9V10uF

62

1.2k

25k

25k

5.1k 1.5k

TMS-3914LED Bar Graph

Figure 11.13. Circuit Diagram for the Device.


VOICE SPECTRUM ANALYSIS Project Engineers: Cheryl Bernstetter, Tanya Hylden, Scott Swanson

Client Coordinator: Louise Dignan, Human Communications Associates, Fargo, ND Supervising Professor: Dr. Jacob Glower



INTRODUCTION Learning to speak can be a difficult process. Even the smallest of words must be heard repeatedly over time before a plausible resemblance of the word is uttered. This process of auditory recognition is the primary method of learning to speak.

For individuals with hearing impairment, learning to speak may seem impossible. Limited auditory ability makes learning to speak difficult. Sign language and obtaining feedback from a hearing person may be the only means of communication for individuals with hearing impairment. Many of the electronic speech labs on the market can be very costly, cumbersome, and difficult to operate. In addition, learning to use these devices requires person-to-person contact, which can be a drain on a speech-language patholo-gist's time and resources.

With these obstacles in mind, the project engineers set out to design a method for helping individuals with hearing impairment learn to speak and pronounce words accurately.

SUMMARY OF IMPACT The portable PC and software will be tested and monitored by a professional from a communications firm starting in the summer of 1998. The feedback ob-tained through the initial use of the device will even-tually lead other design groups to improve the device to make it usable by any speech-language pathologist and/or client.

TECHNICAL DESCRIPTION Design Approach: One of the desired outcomes of this project was to use the clients' visual ability to help them learn to speak. Linguistic sounds can be broken up into distinct components called phonemes. Phonemes are com-

bined to form words. Phonemes are audibly distinct due to their formants, which are unique groups of waveforms of varying frequency and intensity. Spectrograms display these groupings, providing a visual representation of speech graph indicating time, frequency and intensity. This display would distinctly show the groupings of the waveforms, their frequencies, and their intensities, thereby giving a display unique to each word.

For example, the word “speaking” is displayed in a spectrogram on the following page. The horizontal axis displays time, starting with the /s/ sound on the left and ending with the /ng/ sound on the right. The vertical axis displays frequencies, starting from DC on the bottom to 10kHz on the top. Intensity is displayed showing the strongest sounds in bright colors and the weakest sounds in dark colors.

The /s/ sound contains a large amount of white noise and is seen by the first 20% of the sound. The /p/ is a sharp spike just after the quiet dark zone, one third of the way from the beginning of the word. The long /e/sound shows a clean signal with a strong overtone. /k/ is a sharp noise 70% of the way through the word. A soft /i/ followed by a /ng/ sound completes the word.

A desired outcome of this project is portability and user friendliness. If the software interface is written to be user-friendly, this teaching aid could be used independently of the speech-language pathologist. If it is designed to be portable, the client could take the device home and out into diverse environments, in-creasing the amount of practice time available to the client.

Cost is the greatest concern for this project. Most other electronic speech tools are very expensive, cost-ing up to $20,000. A lower-priced tool would enable


more speech pathologists to acquire this technology for their labs, increasing the resources for their clients.

In order to meet the desired outcomes, a laptop PC was selected for this project. These computers meet the requirement for portability, cost less than $2,000, have voice inputs built in, and have graphical dis-plays as required for this project. Further, by develop-ing software for a laptop PC, anyone who owns a PC will be able to use the software free of charge.

Functional Description Software routines were written for the PC using MATLAB.

First, the target signal must be chosen. This target de-fines the "correct" pronunciation of the word and serves as a target the patient is trying to match. Two options exist here: either a previously recorded .WAV file can be used as the target signal or a new .WAV file can be created. This flexibility allows the patient to use the device on his/her own time independent of the speech-language pathologist by using previously recorded files. The speech-language pathologist can also record new words for his or her clients as pro-gress is made.

Next, once a target signal is selected, the spectrogram of the target signal is displayed on the top half of the screen using several modified MATLAB routines.

Once displayed, the operator is prompted to try to match the word. A .WAV file is created, recording whatever the operator says. This file is then con-verted to a spectrogram and displayed on the lower half of the screen.

At this point the similarity or difference between the target and the attempt should be apparent.

If the operator wishes to try again, he/she may go back to the sound recorder, create a new .WAV file, and display the new attempt.

The cost for this project was approximately $2,500 - due to the requirement of a portable PC for the project and compilers for the design group. Once the soft-ware is finalized and compiled, the cost to the user should be nothing. If the user has a PC with Win-dows 95 and a microphone, he/she must simply in-stall the software.

Figure 11.14. Spectrogram of the Word "Speaking."

135

CHAPTER 12 NORTHERN ILLINOIS UNIVERSITY

Department of Electrical Engineering DeKalb, IL 60115


Mansour Tahernezhadi (815)-753-8568 Xuan Kong (815)-753-9942


VOICE PITCH ANALYZER Designers: Kumiko Tsuda, Von Monmany Richard Kwarciany, Jeff Schonhoff

Client Coordinator: Kelly Hall, Department of Communicative Disorder Supervising Professors: Dr. M. Tahernezhadi, and Dr. X. Kong

Department of Electrical Engineering Northern Illinois University (NIU)

DeKalb, IL 60115

INTRODUCTION A portable device for monitoring voice pitch was de-signed for patients with speech impairment. The port-able device assists therapists and their patients in ac-quiring information on episodes of exceedingly high pitch in everyday conversations.

SUMMARY OF IMPACT Speaking with unusually high volume and/or high pitch is believed to cause pathological conditions to the vocal cords, such as vocal nodules. Chronic hoarseness, breathiness, or complete loss of voice are the most common symptoms of vocal nodules. Ab-normal voice qualities such as these can be devastat-ing to one's job performance and can have profound psychological effects.

The primary method of treating patients with voice disorders related to vocal abuse is the monitoring of vocal habits. Typically, patients are asked to self-monitor their speaking habits throughout the day and make adjustments in their phonatory behaviors as indicated. This treatment strategy is often unsuccess-ful (although some additional techniques, not de-scribed, here) have proven successful in many cases.

A continuous monitoring device may be more effec-tive in objectively determining the individual's natu-ral voice pattern and providing feedback (through alerting sounds) when excessive high pitch or high intensity is detected. Whenever the normal pitch range is exceeded, the portable unit produces an au-dible tone alerting the patient. In addition, a total daily count is registered to further assist the clinician in monitoring the patient’s progress towards recov-ery. The portable speech analyzer meets the needs of many clients. The unit will ideally lead to fewer office visits and in turn to a reduction in healthcare costs for the patient.

TECHNICAL DISCRIPTION The portable device is battery operated and can be worn around the waist. Signal from either a throat microphone or lapel microphone is sampled and am-plified with an adjustable gain through the onboard A/D converter. Upon acquiring the sampled speech signal, digital signal processing algorithms coded in TMS320C50 assembly language perform voice pitch level calculations. The DSK board will generate a beeping sound if the voice pitch exceeds a preset threshold recommended by the clinician. The pattern of the audible sound is programmable based on the preference of the patient.

The main design requirements for this project were that it be: 1) portable and as small as possible for the patient to wear around the waist without any discom-fort; and 2) microprocessor based for ease of entering the patient-dependent parameters and for maintain-ing a log of episodes.

The design is carried out on the Texas Instruments TMS320C50 digital signal processor (DSP) DSK board. The fixed point TMS320C50 DSP provides 10 K of on chip RAM with an instruction cycle of 50 nsec. The DSK board comes with the Texas Instru-ments TLC32040C Analog Interface Circuit (AIC). The AIC is a highly integrated component that com-bines the functions of a 14-bit A/D, a 14-bit D/A, in-put anti-aliasing filter, output reconstruction filter, and a serial CPU interface. The AIC can be pro-grammed for various sampling rates, anti-aliasing frequencies, and input gains.

For the portable speech analyzer, the input speech signal from the microphone pre-amplifier is sampled at 8K Hz by the AIC. The algorithm for the portable speech analyzer uses two buffers of size 240 points (one frame). While one buffer is being filled, the other is processed. Four buffer status flags are used to con-

Chapter 12: Northern Illinois University 137

trol processing. The RBUFSEL flag is set to controls which of the two input buffers are currently being filled. PBUFSEL controls which buffer is being proc-essed. BUF1RDY and BUF2RDY indicate that the corresponding buffer is full and ready to be proc-essed. The main processing loop continuously checks for a full buffer. Upon finding a full buffer, the subroutine for the power calculation is called. Dur-ing the processing, the other buffer is filled by the in-terrupt service routine (ISR). In the power subrou-tine, the power associated with the 240 samples in the buffer is calculated. The calculated power value is then added to a running sum that calculates the aver-aged power of 10 consecutive frames. The averaged power is then compared with a set threshold. If the averaged power exceeds the threshold, then a warn-ing tone is generated. If desired, the output warning could also be realized in the form of a mechanical vi-bration. Data in the buffer are analyzed for the largest sample in the first and last third of the buffer to de-termine a clipping value. Two-thirds of the smaller of the two peak values is used to clip the data prior to pitch estimation routine as to remove components due to formant frequencies.

The Autocorrelation Method and Average Magnitude Difference Function (AMDF) method are two methods used for calculation of vocal pitch. Auto-correlation is a technique used to emphasize the periodic peaks and de-emphasize the non-periodic portions of a sig-nal by taking the windowed sum of lagged products of the signal. Auto-correlation shows a maximum at a first non-zero lag equal to the phonatory pitch. The AMDF method takes the absolute value of the win-dowed difference between lagged signal samples. The non-zero lag with the deepest value of ∆MDF indi-cates the pitch period. The pitch information is aver-aged over several frames. If the averaged pitch value exceeds a preset pitch threshold a warning sound or a mechanical vibration is produced.

The size of the portable unit is 4 5/16 by 2 11/16 by 2 1/16 inches. The housing contains the DSK board, the microphone preamplifier, the beeper unit, and the batteries. The portable unit consumes three 9-volt al-kaline batteries. The DSK board itself runs from two 9-volt batteries (+9 and –9 volts) and the microphone

preamplifier also requires a separate 9-volt supply. The current consumption during the loading of code from PC to the DSK is 240 mA with a minimum re-

quired voltage of 6.00 volts. During processing, the current consumption drops to 100 mA with a mini-mum required voltage of 4 volts. In order to save on battery life, in the absence of any input voice signal, the processor is put into the idle mode (via software) where the current consumption can be further dropped to 50 mA. The overall continuous running time for the portable unit is approximately 3 hours.

A three-digit display can also be incorporated to the design to display the number of times excessive pitch or high intensity occurred. A programmer BCD counter with asynchronous RESET (74HC160) is used. The BCD output is directly fed to the BCD-to-Seven Segment latch/decoder/display driver (74HC4511). A common cathode 7 segment LED dis-play is directly connected to 74HC4511. This ar-rangement is identical for all the three digits. How-ever, the ripple-carryout output of the counter driving the least significant digit must be given as the clock input to the next counter. The RESET and LOAD pins of the counters are tied to the supply.

The device was tested for detecting various levels of high pitch or voice signals, and in each case the de-vice was successful.

The final cost of the project is approximately $200.

Figure 12.1. Portable Speech Analyzer Internal View.


A DSP-BASED WIRELESS INFANT MONITORING DEVICE FOR INDIVIDUALS WITH HEARING

IMPAIRMENT Designers: Jeff Ciarlette and Greg Stringfellow

Supervising Professors: Drs. M. Tahernezhadi, X. Kong Department of Electrical Engineering Northern Illinois University (NIU)

DeKalb, IL 60115

INTRODUCTION A portable wireless device was designed to enable an individual with hearing impairment to monitor an in-fant by detecting when the infant is crying. The re-ceiver of the device can be housed like a pager and, in effect, page the individual with hearing impairment each time the infant cries.

SUMMARY OF IMPACT Persons with hearing impairment are often unable to use intercom-type infant monitoring devices. There-fore, alternative devices are essential. This infant-monitoring device relies on a digital signal processor to detect infant crying sounds. Once crying is de-tected, a paging device alerts the user by vibrating and activating a light emitting diode. With such a device, users may conveniently monitor an infant and still complete other household activities. The wireless DSP-based infant-cry-recognition system serves as a cost effective and convenient device for enabling an individual with hearing impairment to monitor an in-fant.

TECHNICAL DISCRIPTION Digital signal processing and wireless transmission are the two primary technologies employed in the de-velopment of this device. Digital signal processing is used to recognize the sound of an infant crying. Sound recognition is accomplished in real time through the use of a digital signal processor (DSP). The device utilizes the TMS320C50 DSK board, a low-cost DSP board equipped with 14-bit input/output analog- to- digital (ADC) and digital-to-analog (DAC) converters. The DSP receives a signal from a micro-phone located near the infant. Employing digital sig-nal processing algorithms, the DSP determines if the

microphone signal has the same properties as those of an infant crying. The DSP then sends a control signal to a wireless transmitter. The transmitter sends a digital code to a receiver using frequency shift keying modulation technique. Upon detecting the code, the receiver vibrates and activates a light emit-ting diode.

The design requirements for the wireless monitoring device were that it: 1) be able to recognize infant cry-ing sounds; and 2) consistently alert the caretaker of infant crying via a wireless system.

The infant crying sound detection is carried out on the Texas Instruments TMS320C50 digital signal processor (DSP) DSK board. The input speech signal from the microphone pre-amplifier is sampled at 8K Hz by the AIC. One can assume that the environment in which the infant-monitoring device operates will be relatively quiet. Sounds such as doors opening and closing and people moving past the device will probably be the extent of the common noises in the environment.

Speech recognition relies on the speaker to vocalize clearly and at a reasonable volume. Since infants do

DSP TransmitterMicrophone w/Preamp

Receiver VibrationDevice

PAGER

Figure 12.2. Block Diagram of the Wireless Infant Monitoring Device.

Chapter 12: Northern Illinois University 139

not make precise crying sounds at distinct volumes, the methods used to identify the crying sound are based on short-term energy and zero-crossing analy-sis. Short-term energy is the energy contained in a fi-nite length of the signal. It is defined as the sum of the squares of the samples in the 20 msec segment sliding on a sample-by-sample basis. Once the short-term energy exceeds a preset threshold, the algorithm indicates that an infant crying sound may be present. The threshold is chosen so that very quiet or distant sounds will not cross the threshold.

To make use of short-term energy practical, the mi-crophone preamplifier was designed with adjustable gain. This gives the user some degree of freedom as to how far the microphone can be placed from the infant simply by increasing the gain with distance. The sec-ond part of recognition is based on zero-crossings. Zero-crossings are the number of times the signal crosses the zero axis. There was an obvious trend in zero-crossing any time the infant started to cry. As a result, it was determined that using zero-crossing in conjunction with short-term energy could provide a suitable method for determining if the sound was the infant crying. The only concern was that other com-mon sounds would also share these characteristics. It was determined through real time testing that most sounds such as talking in a normal tone and doors closing were not recognized as the infant crying.

The firmware for this project consisted of a Texas In-struments TMS320C50 Digital Signal Processor mounted on small evaluation board called a DSK board. The DSK consists of the DSP, a power supply, an analog interface, two RCA sockets for analog input and output, and an RS232 connection to communi-

cate with a personal computer. The entire evaluation kit also included a debugger, an assembler, an in-struction manual, and sample programs that were used to develop the DSP program. A Texas Instru-ments TMS320C50 digital signal processor was used. It is operated at approximately 40 MHz and is only capable of fixed-point operation. The arithmetic logic unit (ALU), the accumulator, and its buffer are 32 bits. The TMS320C50 has 2K x 16-bit on-chip ROM, 9K x 16 bit on-chip RAM, as well as 1056 x 16 bit on-chip data RAM. It also contains 64K I/O ports and two se-rial ports for input and output.

The DSP was programmed to fill a buffer of samples with a length of 20ms. Since the analog to digital con-verter was programmed to sample at 8000 Hertz, the buffer contained 160 samples when filled. For each subsequent input sample, the oldest sample in the buffer is overwritten by the new input. Each time the buffer is updated with a new sample, its short-term energy is calculated. The energy is then compared to the threshold number stored in memory. The thresh-old level of the signal was determined in the simula-tion. If the energy exceeds the threshold, the DSP cal-culates the zero-crossings in the buffer. The number of zero-crossings found in the buffer is then compared to two values specifying the valid range of infant cry-ing zero crossing. These values were also found by analyzing the simulation results. If the number of zero-crossings falls between these two numbers, an output signal is sent from the DSP to the transmitter. The transmitter sends this signal, using frequency shift keying modulation technique, to the receiver, which activates the pager. The final cost of the pro-ject is approximately $300.

Figure 12.3. DSP-Based Wireless Infant Monitoring De-vice for Hearing-Impaired.

141

CHAPTER 13 STATE UNIVERSITY OF NEW YORK AT

BUFFALO School of Engineering and Applied Sciences

Department of Mechanical and Aerospace Engineering 335 Jarvis Hall

Buffalo, New York 14260-4400


Joseph C. Mollendorf (716) 645-2593 x2319 [email protected]


OPHTHALMOLOGIST’S OPTICAL LENS HOLDER FOR SLIT LAMP EYE EXAMS

Student Designer: David Leff Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department

State University of New York at Buffalo, Buffalo, NY 14260-4400

INTRODUCTION A slit lamp test allows an ophthalmologist to view the cross-section of an eye. A doctor holds a circular lens approximately the size of a quarter near the patient’s eye. Next he or she looks through a slit lamp to view a cross-section of the eyeball. The exam may be diffi-cult to perform if the doctor does not have full dexter-ity and strength in his or her hands.

This device addresses the client’s need to perform the slit lamp test. As a consequence of amyotrophic lat-eral sclerosis (ALS), the client has not been able to administer this test because of his inability to fully ex-tend his fingers. Also, his wrists are weak which de-creases his ability to manipulate the lens.

The client is able to grip objects that are roughly the same size and shape of a broom handle. The primary goal of this project was to design and construct a de-vice to maximize the doctor’s limited strength and dexterity allowing him to perform the slit lamp exam. Another goal was to make the device aesthetically pleasing.

A lightweight device in which the lens could be in-serted with a handle similar in size and shape of a broom handle was constructed. The shape and weight of the tool are designed for the ophthalmolo-gist to hold the lens near the patient’s eye, while pre-venting the device from becoming obtrusive to the pa-tient.

To increase the comfort of the device for the patient, a nosepiece was added to avoid the nose (Figure 13.1). A viewing port allows the patient to focus on a dis-

tant object through the bridge of the optical lens holder.

SUMMARY OF IMPACT The ophthalmologist with ALS uses the device to per-form the slit lamp test. However, he continues to re-quire assistance in lifting the eyelid of a patient. This device allows him to perform a standard portion of an eye exam and to maintain his professional ability.

TECHNICAL DESCRIPTION To meet the criteria of a lightweight, durable and aes-thetically pleasing device, a composite material of foam and fiberglass was utilized. To address preci-sion fit of the lens, a nylon insert was machined.

The device began as a foam cutout, the same size and shape as the finished lens holder. Three layers of a lightweight fiberglass (microglass) were glued to the foam with epoxy resin and allowed to dry. The use of fiberglass-coated foam gives the device a higher weight-to-strength ratio than titanium. To further in-crease the compressive strength of the device, an ep-oxy/glass microsphere filler was applied to the sur-face and allowed to dry. The device was then sanded and applied with a coat of primer to provide a neat finish. To eliminate unwanted reflection during an eye exam, the lens holder was painted a flat black. An improvement for the design may include the addi-tion of a device to lift the eyelid above the lens.

The total cost of materials and supplies was ap-proximately $35.

Chapter 13: State University of New York at Buffalo 143

Figure 13.1. Lens Holder as Seen by User.

Figure 13.2. Top View of Lens Holder.


WHEELCHAIR STEP NEGOTIATOR Student Designers: Yik Kan Leung, Matthias Kolodziejczyk

Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION The objective of this project was to design and build a portable ramp to enable a person in a wheelchair to safely climb one to three steps without a permanent ramp. By allowing the user access to elevated areas, the ramp decreases reliance on passers-by, thereby increasing the user’s independence.

SUMMARY OF IMPACT A major aspects of the ramp design is a braking fea-ture, providing the wheelchair user time to move and grasp the rear wheels after completing the action of moving the chair forward. Additional features in-clude its small storage size, tall guide rails, and sev-eral safety features.

TECHNICAL DESCRIPTION The main design constraints for the ramp were its weight and size. The length of the ramp is fixed, ne-cessitating extension to a length of eight feet.

Aluminum was used because of its high strength-to-weight ratio and low cost. To further reduce user burden the conventional large track was divided into two smaller tracks that may be deployed one at a time.

Each ramp is composed of three sections that tele-scope in and out of each other. When extended to the maximum length, the 36-inch sections reach a total length of eight feet forming an ascension angle (the angle between ground level and the ramp) of 10.8° when raised to a height of 18 inches. With the brak-ing feature described below, the majority of users will be able to use this ramp design to gain access to ele-vated areas.

Each section of the ramp is made up of two aluminum C-channels and a base plate. The two C-channels are welded onto the sides of the base plate. The C-channels provide the necessary support and act as guide rails for the user’s safety. The placement of the

C-channels also prevents the wheelchair from moving

backwards. Since the front wheels must rotate 180 degrees for the wheelchair to change from moving forward to backward, with a distance of 7 inches be-tween the guide rails, the front wheels do not have sufficient room to rotate the full 180 degrees required for the change between forward and reverse move-ment. Instead the front wheels rotate approximately 60 degrees before being stopped by the guide rails and thus are prevented from moving backward. This braking effect stops the wheelchair from unintention-ally rolling down the ramp and allows the user time to grasp the rear wheels after moving forward.

The outer section is 3 5/8 inches high by 9 and 5/8 inches wide. The middle section is 3 and 5/16 inches high by 9 and 5/8 inches wide, and the inner section is 3 inches high by 9 inches wide. All three sections

When the inner section is fully protruded, a peg lo-cated on the inner section locks the inner ramp to the middle ramp, thus locking both the inner and middle

Figure 13.3. Wheelchair Step Negotiator.


section in place with a 6-inch overlap. This prevents the inner section from sliding apart from the rest of the ramp. The middle section also has a similar peg to lock onto the outer ramp.

The ramp will not deflect or bend when supporting a weight of 500 lbs or less, thereby enhancing the cli-ent’s sense of stability and safety.

The total cost of materials and supplies was about $180.


BOOK RETRIEVER Student Designers: Maya L. Easley, John Evan W. Gorski, Sanjeev Khurana



INTRODUCTION Some individuals have difficulty using library facili-ties effectively due to limitations with reaching. Av-erage library shelves ascend to approximately seven feet. However, the reaching limitations of an individ-ual using a wheelchair are between four and five feet. The lower shelves are accessible, but additional assis-tance is required in retrieving books from beyond five feet.

The presence of a book retrieval device within library facilities may have a positive impact by increasing accessibility for patrons with disabilities and other individuals who have difficulty reaching books from high shelves. Along with increasing accessibility, the Book Retriever enhances independence for individu-als with disabilities.

The Book Retriever incorporates features of reaching devices currently on the market. However, such de-vices are generally designed to handle small objects, such as pieces of paper or articles of clothing. De-vices currently on the market do not possess the strength and durability needed to grasp large, rela-tively heavy books. Therefore, a much sturdier device was necessary.

SUMMARY OF IMPACT The Book Retriever assists individuals in obtaining books from shelves above their reach. It will allow li-braries to be more accessible to patrons with disabili-ties.

TECHNICAL DESCRIPTION The Book Retriever is composed of the following six components: cable, arm, hook, and chute, and a bicy-cle brake lever with calipers. All parts except the cali-pers and cable are aluminum. Aluminum was chosen as the main material due to its high strength-to-weight ratio.

The development of this device evolved through in-vestigative processes of observation, simulation, analysis, experimentation, and evaluation. When reaching for or removing a book from a shelf, a person hooks the book with a finger to pull the book from the rest and then grasps the book. Thus, the optimal de-sign closely simulates the hand and limb motion in-volved in book retrieval. For this reason, a hook and jaw (caliper) system was used.

The brake handle, calipers, hook, and chute are mounted on the arm. The arm is constructed of alu-minum tubing with an outside diameter of 7/8” and a length of 50 3/16”. The caliper is 4 ½” in length and has a maximum span of 1 ¾”. The calipers have a quick release mechanism allowing the operator to reduce the span for grasping thinner books. To close the calipers, a brake handle is squeezed, similarly to a bicycle brake. A cable attached to the lever and the calipers follows the motion of the lever and pulls the calipers closed. The hook snags the top of the book-binding and tilts the book forward enable the opera-tor to grab the book with the calipers. Once this is accomplished, the book is released into the chute where a net is attached to catch the book. A spring hinge attached to the chute allows the chute to be bent back when pressed against the bookshelf. This elimi-nates interference of the chute while using the hook

Figure 13.4. Shelf Book Retriever.


and calipers. The weight of the Book Retriever is 2.5 lbs and the mechanical advantage is six.

The designers would like to thank the following peo-ple for their cooperation and efforts: Edward Herman for his insight and previous knowledge of working with the Americans with Disabilities ACT (ADA) subcommittee in dealing with handicapped accessi-bility on campus, Professor Colin Drury in the Indus-

trial Engineering Department for his vast knowledge of ergonomic design, and Kenneth Peebles and Roger Teagarden for their help in converting the design from paper to a working prototype.


Figure 13.5. Calipers, Hook and Chute.


PORTABLE LIFT FOR WHEELCHAIRS Student Designers: James K. Adams and David Leff Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION Height differentials are often difficult obstacles for people in wheelchairs. Available devices to assist in the negotiation of such obstacles are generally expen-sive and bulky. The main purpose of this project was to design and construct a portable device to assist a person in a wheelchair independently negotiate height differentials of up to 18 inches. Such a device will help persons in wheelchairs ascend curbs, trans-fer into and out of wheelchair transport vehicles, and ascend other such height differences. A permanent ramp, curb cut, or wheelchair conversion van would not be needed.

SUMMARY OF IMPACT An assistive device was successfully constructed to safely lift the wheelchair to the expected height. It has a compact, sleek design for increased comfort of the operator. The lift rises simply by manual inflation with an air pump. When deflated, the lift can easily be stored in the trunk of a car or the back of a van. The airlift is rated for a 300-pound load.

TECHNICAL DESCRIPTION The appeal of the airlift is its weight (approximately 40 pounds) and storability (deflates to about 36” x 24” x 4”). The lift is constructed of one 19” x 19” heat-sealed, reinforced, nylon/urethane bellow sup-plied by Gagne, Inc. The bellow weighs approxi-mately two pounds. The bellow was manufactured with pre-drilled bolt holes around the perimeter. On the top and bottom of the bellow are 36” x 24” x ¾” plywood plates. The plates are mounted on the bel-low with three-quarter inch machine screws set into an aluminum flange plate and rubber gasket. When the bellow is inflated with a simple, double-action air pump, the wheelchair is raised. The airflow can be regulated by the quick disconnect valve.

Limiting horizontal movement during inflation was important. Scissor-action metal crossbars were thus

used for stabilization. 1018 cold-rolled steel was used for the bars and angles. The two bars on both 36” sides are pinned together at the center with shoulder bolts. One McGill cam follower was used on each bar to allow smooth motion along the track on the angle iron. The track was welded using 7011 rod. Increased stability may be achieved by adding crossbars to the two remaining sides.

While steel supplies exceptional strength and stabil-ity at a low price, it adds substantial weight. Substi-

Figure 13.6. Portable Lift in Down Position.


tuting high-strength plastic crossbars would substan-tially decrease the weight, but would increase manu-facturing costs. High strength-to-weight, fiberglass foam plates may be substituted for the wood, decreas-ing the weight as well. This would also significantly increase the total cost of production. These advanced modifications would decrease the total weight of the lift by more than half.


Figure 13.7. Portable Lift in Raised Position.


ASSISTIVE GLOVE: A MECHANICAL EXOSKELETON TO AUGMENT HAND STRENGTH

AND CONTROL Student Designers: Sean Selover and Piotr Frey



INTRODUCTION Some individuals cannot use their hands to perform daily tasks. An assistive glove was developed to augment hand strength. Ideally, the glove allows the individual with a disability to sustain a tighter grip on various objects.

The assistive glove is designed to aid people who suf-fer from muscle injuries or diseases of the nervous system, such as myasthenia gravis or muscular dys-trophy. These diseases may cause people to lose con-trol in their hands. In such situations, people are un-able to perform necessary tasks and must rely on as-sistance from others. The glove compensates for the individual’s lack of motor control by replacing the mechanisms necessary for flexion of the hand and phalanges. The glove requires minimal use of the in-dividual’s thumb for proper operation.

SUMMARY OF IMPACT The use of the assistive glove returns some lost func-tions of the debilitated hand. While wearing the de-vice, a person can pick up and hold objects from 0.5 to about 4 inches in diameter. The glove can also be used to carry larger objects (boxes or piles) where the hand needs to be hooked. The glove demonstrates mimicry of the components responsible for flexion of the human hand.

One disadvantage of the glove is a loss of sensitivity, resulting from the lack of contact between the object surface and the palm and fingers. The greatest ad-vantage is increased independence.

TECHNICAL DESCRIPTION The device consists of two components, a wrist brace manufactured by DONJOY® and a flexible hand piece attached to the brace. The user places his or her hand on an object and, using the opposite hand, pulls and fastens the wrist lever, causing the glove to wrap around an object. The hand-piece is designed to closely mimic the mechanics of the human hand. It consists of three movable sections (with effective length corresponding to the finger length) connected to each other. This allows the links to bend together, in the way that fingers of a hand wrap around an ob-ject while holding it.


Figure 13.8. Assistive Glove.


Figure 13.9. Grabbing Mechanism Being Activated.


EMERGENCY VACUUM-PACKED NECK SUPPORT

Student Designer: Tomasz R. Targosz Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION The objective of this project was to design a neck sup-port for emergency purposes. The neck support is for temporary use only, up to two hours. Commercially available neck supports do not provide the maximum support possible.

The vacuum-packed coffee sold in grocery stores in-spired key features of the design. The requirements for the neck support were that it: be rigid when in use, provide custom fit, permit production in large quanti-ties, take up as little space as possible when in stor-age (preferably to be stored flat), and be inexpensive to manufacture.

SUMMARY OF IMPACT The vacuum-packed neck support is an excellent sub-stitute for current neck supports. It provides a greater amount of support while meeting the storage and cost requirements.

To apply the neck support, one must wrap it around a patient’s neck and engage the Velcro. The vacuum is drawn using a manual vacuum pump. For final ad-justment, the Velcro is disengaged, the fit of the neck support is tightened, and the Velcro is re-engaged. The final adjustment is necessary to reduce a gap be-tween the neck support and the patient's neck, which results from a decrease in volume as the particles in-terlock.

TECHNICAL DESCRIPTION Rigidity was the most crucial requirement of the de-sign. Drawing vacuum and interlocking the filler ma-terial particles with each other ensured rigidity. Other filler materials were used in experiments (poly-lite gardening product and ground coffee grains.) The advantage of polylite is its low cost, but the dis-advantages outweighed that advantage. Polylite is a

brittle material. When pressure is applied, polylite disintegrates into dust-like particles. The filler mate-rial must remain intact before and during use. The advantage of ground coffee grains was their resis-tance to disintegration, provided they were well ground. The coffee grains also interlock well with each other. The disadvantage of coffee is its high cost.

Figure 13.10. Neck Support as Worn Evacuated.


Although the coffee is not the ideal solution, it dem-onstrates that the principle works. For commercial purposes coffee can be substituted with materials with similar properties, such as gravel.

When the pressure in the neck support equals the at-mospheric pressure inside the neck support, the neck support is flexible and molds to the contours of the person’s features. As the vacuum is drawn, the filler material particles interlock, creating a rigid structure that remains in the previously assumed shape. The neck support can be stored flat when not in use, which allows for stacking (see Figure 13.11).

A triangular opening was incorporated to provide ac-cess to the patient’s throat for performing an emer-gency tracheotomy.

A one-way valve was necessary to allow the air to be evacuated and to prevent the air from entering the in-side of the neck support when in use.

A Velcro strap was attached to both ends of the neck support to allow it to be kept in a wrapped position when in use.


Figure 13.11. Neck Support in Storage Configuration.


SHOWERHEAD-ATTACHABLE SOAP AND SHAMPOO DISPENSER

Student Designer: John A. Kyprios Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION The showerhead-attachable soap and shampoo dis-penser was designed for persons who experience dif-ficulty showering due to a disabling condition, such as arthritis or muscle weakness. This device assists people in showering by automatically mixing clean-sing material with water. This mixture results from dripping the cleansing material (soap or shampoo) into the oncoming flow of water from the shower-head.

SUMMARY OF IMPACT The device uses no electrical power nor pumps and is built with inexpensive parts. It works with the natu-ral force of gravity. The device has the following three major components: the material chambers, the hose equipment, and the bracket.

The soap and shampoo are stored in the material chambers. The chambers are connected to the hose equipment, which, when all components are assem-bled and attached, is located directly over the show-erhead. These two pieces comprise one unit adhered with epoxy. Velcro links this unit to the bracket, which is connected to the pipe leading to the shower-head.

An advantage of this device is that the plumbing of the shower remains unchanged, resulting in easy de-tachment and attachment to the shower as needed.

TECHNICAL DESCRIPTION The chambers containing the cleansing material are made of Plexiglas. The pieces used were cut specifi-cally to fit in baths where the clearance between the shower pipe elbow and the ceiling is small. For the shower where all testing was completed, the clear-

ance is less than 4 inches. This resulted in a compact design. The various pieces were cut and connected with silicon sealant glue to make a box 6 inches wide and 3.5 inches high. The bottom rear of the box was tilted upward to ensure a proper flow of material. The front side of the box was tilted for the same rea-son. A Plexiglas piece was placed in the middle of the box to separate it into two chambers for soap and shampoo.

The hose equipment was connected with epoxy to two 0.75-inch holes located in the outer bottom cor-ners of the front piece of the box, one in each chamber. The main piece of the hose equipment is the Y-valve. This is the control valve for the cleansing material flow. At the fully closed position, there is no flow of material. This is the shutoff for the system. Attached to the Y-valve are two plastic elbow tubes from where the cleansing material flows and meets the water coming out of the head. Where the plastic tubes con-nect to the Y-valve, a Plexiglas piece was inserted into the Y-valve to separate the two flows of material to prevent the mixture of soap and shampoo.

Finally, the bracket was made of Plexiglas pieces con-nected by silicon. The bracket has two hose clamps, allowing a connection to the shower pipe elbow. The bracket and chambers/hose equipment combination are joined with Velcro for ease of detaching and refill-ing.



Figure 13.12. Showerhead-Attachable Dispenser.


AUTOMATED GARBAGE BAG SEALER Student Designer: David Cheung



INTRODUCTION A garbage bag sealer can be used for effortless, neat, and odor-free disposal. Current garbage bag sealers are mainly for diaper disposal. There is no similar design for the household garbage bag on the market. The problem with sealers currently available is their limited size. A sealer makes a knot by twisting the end of a continuous plastic bag when a diaper is in-serted.

This device will benefit people who are physically unable to tie a knot in a bag. The heat sealer provides many advantages compared to the conventional ways of disposing garbage. The heat sealer creates a com-plete seal across the bag, preventing leakage of odors. There is no need to hold the bag to apply a twist-tie or to make a knot.

SUMMARY OF IMPACT New technology allows the use of heat to seal bags for easy, sanitary, and odor-free disposal. An advantage of the device is that only one hand is needed for op-eration. The device helps people who have difficulty making a knot in a garbage bag.

This device is designed for household kitchen use. With an attachable frame, it fits on most rectangular garbage cans (13 gallon capacity) with dimensions of 10 ½” x 15”. The device is designed to use AC power as it will be used in the kitchen. Unlike other knot-making devices, there is no need to replace accesso-ries (such as metal strips) because this device uses only electricity.

TECHNICAL DESCRIPTION The project is divided into two components, the frame construction and the heat-sealing device. A hand-operated impulse bag sealer from ABTEC, Inc. was used to develop the garbage bag sealer.

The following are the parts of the heat sealer: heating element, micro-switch, adjustable timer, and a high-to-low transformer. When the sealer is activated, an AC current flows through the transformer to reduce the voltage from 120 volts to 20 volts and then through to the heating element. The heating element warms when current flows through it to perform the sealing. When uniform pressure is applied, the bag is sealed smoothly.

To provide variety, a timer can be set from 0.5 to 2 seconds for specific amounts of plastic thickness. This enables people to buy different brands of gar-bage bags.

For safety concerns, the device is equipped with an adjustable timer to prevent over-heating or fire haz-ards. The device deactivates when sealing is com-plete. A micro-switch is used to control the device. The switch operates only when the gap between the sealers is closed. Preventing children from placing their fingers in the sealers is of paramount concern.

The device is operated at high-energy efficiency. There is no warm-up time required, and it only uses electricity within the set time.

The frame structure is built with lightweight alumi-num, and the attachable frame is built with thin metal sheet. Both are easily managed, as neither is heavy. The inner frame is attached to the outer frame with rivets. This allows people to remove the garbage bag from the can once sealed.

The heating element is mounted inside the inner frame. There is a bar that slides across the frame to close the gap with the heating element. A string is used to pull the bar across from the other side of the frame. To decrease friction between the bar and the frame, Teflon bushing is used as a bearing.



Figure 13.13. Automatic Garbage Bag Sealer.


ADJUSTABLE ANKLE SUPPORT TO RELIEVE COMPRESSIVE FORCES

Student Designers: Adam S. Lurie, John E. Harder III and Jonathan K. Hammond Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION Many people experience discomfort from compressive forces on the ankle as a result of injury or disability. Such injuries include a broken foot or ankle, a dam-aged Achilles’ tendon, bone spurs, ligament damage, foot surgery, and arthritic ankles. Current ankle sup-ports alleviate only plantar flexion and do not ac-count for compressive forces.

This device transfers compressive forces from the an-kle to the mid-tibial region of the shin, allowing peo-ple with the aforementioned injuries to walk without pain. As the ankle heals, increased force may be ap-plied for rehabilitative purposes as the user walks.

SUMMARY OF IMPACT The adjustable ankle support assists people in both the healing and rehabilitation phases of their recov-ery. Ankle braces used currently cannot be worn un-til the ankle is sufficiently healed because such braces do not transfer compressive forces away from the an-kle. Consequently, leg muscle atrophy is common. The ability to vary the compressive forces on the ankle allows this device to be utilized at an earlier stage of healing. The use of this device will decrease the re-habilitation time and reduce the need for crutches.

TECHNICAL DESCRIPTION The basic design began with a DONJOY High Tide Walker, part number 11-0179-x-06136. This walker consists of a washable leg sock and a plastic foot piece with a molded rocker bottom for ease of walk-ing. Riveted to the foot piece are two flap aluminum bars. These bars follow the contours of the muscle. There are three Velcro straps covering the length of the aluminum bars. The sock and straps are adjust-able with respect to the position of the bars. Three

other Velcro straps were attached to the foot piece and were not position-adjustable. Two of these straps were connected to the aluminum bars.

The first modification to the DONJOY brace required cutting through the flap aluminum bars 1 ¼” from the foot piece to remove the Velcro strap loops from the bars. Two shock absorption devices were then at-tached to control the distance of heel travel.

Each device consists of an upper and a lower tube. The lower tube has a bolt welded to the top and slides inside the upper tube. The upper tube has a washer welded to the top, through which the bolt on the lower tube slides. A nut is attached to the bolt to se-cure the device. Between the tubes is a spring, which controls the extent to which the shock absorber is compressed. This shock absorber is attached to the brace in the following manner: the larger tube is con-nected to the detached aluminum bar, and the smaller tube is attached to the bar and the foot piece. Each pocket consists of an air chamber and a valve stem.

This construction enables the heel to sink into the air pouch, applying a force to the ankle as the springs are compressed. This force is adjusted by changing the air pressure in the pockets. Once the spring is fully compressed, all additional force is directed to the shin.

The design of the adjustable ankle support has been tested, and the concept is successful. Additional in-vestigation into air pocket design could further im-prove this device.



Figure 13.14. Adjustable Ankle Support.


ASSISTIVE CAR SEAT TO FACILITATE

ENTRY AND EXIT Student Designers: Jim Mittag, Jason Gwin, Arthur Trombley III



INTRODUCTION The objective of this project was to design and build an assistive device to aid a person with a physical disability in entering and exiting a motor vehicle. Other devices fitting the overall description are often large and require modification to the vehicle. The in-tent was to design a device that could be easily in-stalled by the consumer with little or no modification of the vehicle. The design was also to be lightweight and as non-intrusive to the operator as possible. Low cost and easy operation were important considera-tions.

SUMMARY OF IMPACT The assistive device was successful in assisting a per-son in the entry and exit of a vehicle. The design mounts on an existing seat with little or no interfer-ence and is easily operated. It provides consumers access to an easy, reliable solution for a common problem and thus has potential to improve quality of life for many people.

TECHNICAL DESCRIPTION The device facilitates entry to and exit from a vehicle with minimal effort from the operator. It operates on a sliding mechanism. The top portion contains a cush-ion on which the person sits. When the person wishes to exit the vehicle, he/she swings his/her legs out of the vehicle and slides the cushion out of the vehicle.

The device consists of three frames. The first frame at-taches to the car seat. Bolts are arranged on this frame to allow for adjustability for different shapes and styles of seats. The second frame contains the shafts for the slider mechanisms. The third frame is the seat cushion and contains the bearings.

The frames were made from 1 ½ inch steel angle. Steel angle was used because of its strength and ma-chinability.

The cushion was made from 1 ½ inch foam, covered with canvas. This was bolted to the frame containing the bearings.

The bearings used were Frelon-lined linear bearings. This type of bearings was used because of cost and performance. The Frelon bearings withstand water and dust better than roller bearings. Before assembly, the parts were painted flat black for aesthetic appeal.

When designing the device, the following key points were considered:

• Stability while the user enters and exits the vehicle;

• Adaptability to different styles of seats;

• Lack of interference with the steering wheel, seatbelts and door opening; and

• Low cost.

The final design meets these criteria. The device does not interfere with any of the existing parts in an automobile. The device is stable in the open and closed position. The total cost of materials and sup-plies was about $200.


Figure 13.15. Assistive Car Seat.


EASY PUMP FUELING DEVICE FOR SELF- SERVICE GASOLINE DISPENSING

Student Designer: Christophe J. Day Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION For many people with arthritis of the hand, or other hand problems, pumping automotive gasoline may be difficult or impossible. An assistive device can sim-plify this routine task by keeping the gas pump on as the tank fills up.

The Easy Pump Fueling Device was designed to pro-vide hands-free support at any basic gas pump. The compact design allows for easy storage on a key chain or in a glove box.

SUMMARY OF IMPACT The focus of the device is to increase the independ-ence of people with disabilities. The completed de-vice meets all of the following design goals: simplic-ity, key chain size, ease of application and removal, and no additional resistance.

Despite the disabling of locking mechanisms on most gas pumps in New York State, this device allows peo-ple with disabilities to once again choose any gas station instead of only those with locking mecha-nisms.

TECHNICAL DESCRIPTION The device is primarily comprised of two compo-nents, the handle and the steepled arm.

The handle is made of a soft, rubbery thermoplastic material. The material for the prototype was obtained from a moldable athletic mouth guard. The geometry of the handle is of great importance. To achieve im-portant details such as a recess and protrusion, it was necessary to make a clay mold in which the heated thermoplastic could be set.

The steepled arm is also composed of a thermoplastic material. The material in the steepled arm becomes relatively rigid upon cooling. A key chain ring is connected to the steepled arm, making the device fail-safe by preventing the client from driving away with-out properly removing the device.

Coupling of the components was completed with a simple ball-socket joint. The ball and socket are stan-dard stock at local hobby shops. Twisting of the arm at the joint is a negative factor and is minimized by the use of a ball-socket joint. The purpose of the joint is to allow a mostly two-dimensional swinging mo-tion.



Figure 13.16. Easy Pump Fueling Device.


STOWABLE WHEELCHAIR UMBRELLA Student Designers: Michael Jordon, Michael Miller, and John Walsh



INTRODUCTION Most people in wheelchairs are not able to hold an umbrella while outside in the rain. A person in a mo-torized wheelchair may not have the strength to hold an umbrella, and a person in a manual wheelchair needs both hands to move.

To keep persons in wheelchairs dry in the rain, a de-vice to attach an umbrella to a wheelchair was devel-

oped. The device is detachable and can be mounted on many types of chairs from the rear handlebars.

Several design factors were important. The arm bringing the umbrella from a stored position to an open position must be easily movable. The stored po-

sition should not interfere with the normal activities of the user. The device must be completely detachable from the chair. When open, the umbrella must be po-sitioned properly.

SUMMARY OF IMPACT This device is intended to improve the quality of life for a person using a wheelchair. The user is kept dry and comfortable.

The device is versatile for easy attachment to different sizes of chairs. This feature increases the impact of the device because more people will be able to use it.

While there are canopies to shield wheelchair users from the elements, the canopies are large, obtrusive-looking, and difficult to store. This umbrella device is more compact, easier to operate, and is stored in a convenient location on the chair when not in use.

The device is easy to move. Retractable cords assist in all movements of the device. Persons with little upper body mobility and strength can use the umbrella.

TECHNICAL DESCRIPTION The device consists of two ¾” steel bars. One straight bar is attached to the rear handlebars of the wheel-chair with four hose clamps. The curved bar, known as “the arm,” is attached to this straight bar, allowing it to swivel. The bars are fitted inside a pair of alumi-num blocks. The blocks rotate with respect to each other with the use of a shoulder bolt. The umbrella is fixed to the end of the arm with hose clamps. The umbrella is also supported with machined sheet steel.

To assist the movement of the umbrella arm, retract-able cords are mounted on the wheelchair near or be-low the armrests. Each cord retractor is attached to the chair by nylon straps enabling the device to be easily adapted to different chairs.

Figure 13.17. Wheelchair Umbrella Stowed.


One drawback of the device is mild difficulty when mounting it on the chair. The device requires the use of a screwdriver or socket to tighten and loosen the hose clamps. Another disadvantage is the complex multi-step procedure required to open the umbrella.

The user may learn the procedure with practice. However, the procedure should be simplified in fu-ture work.


User Instructions for Wheelchair Umbrella

To Deploy

1. Unlock left cord retractor.

2. Pull out cord to black mark.

3. Lock left cord retractor.

4. Unlock right cord retractor (if locked).

5. Grab right cord, extend arm out a little and pull on cord to swing umbrella to the side.

6. Reach out and push button on umbrella (unfolds umbrella).

7. Reel in cord to bring umbrella towards body for coverage.

8. Lock right cord retractor.

To Bring to Stored Position Behind Wheelchair

1. Unlock right cord retractor.

2. Pull out right cord to black mark and lock right cord retractor (provides cord slack).

Figure 13.18. Wheelchair Umbrella Deployed.


WHEELCHAIR PROPULSION DEVICE Student Designers: James Poon, Peter Liu



INTRODUCTION An ergonomic method for manual wheelchair pro-pulsion was developed. Incorporating a relatively higher mechanical advantage, an ergonomically ad-vantageous system was designed, enabling reduced expenditure of energy during manual wheelchair propulsion.

Higher mechanical advantage is accomplished through a four-bar linkage mechanism, which also improves ergonomics with regard to the position of the input forces.

The initial cost of manual wheelchairs (some range to $1000) is prohibitive to the design of a highly inte-grated propulsion mechanism. Modularity was con-sidered in the design of this device to offset the poten-tial high initial costs. Further design considerations include simplicity and aesthetics of the device.

SUMMARY OF IMPACT The primary users of this device will be individuals who already own manual wheelchairs. The reduc-tion of the input forces reduces strain on the back by relocating the point at which the input forces are ap-plied to the arm level.

TECHNICAL DESCRIPTION The existing method of manual wheelchair propul-sion results in a high degree of strain on the user’s back due to a lack of mechanical advantage. The cur-rent system involves a four-bar linkage mechanism that relocates the point at which the input forces are applied and provides improved mechanical advan-tage to the system. The mechanical advantage is fur-ther optimized through fine analysis of the angles and lengths within the linkage mechanism, and an increased output angle to maximize the output with a standard input. This analysis is executed by com-puter calculations.

The highly visible nature of this device further intro-duced the criteria of a compact and aesthetic design. Further considerations included the following:

• Modularity, such that the device could be purchased as an add-on module;

• Compatibility with a majority of manual wheelchairs;

• Simple interface with overall wheelchair sys-tem allowing for easy installation without the use of power tools.

Figure 13.19. Propulsion Device Mounted on Wheelchair


• Flexible usage allowing for movement in for-ward and backward directions.

• Ergonomic quality with reduced input force.

Another goal was a lightweight construction. How-ever, this was offset by the need to incorporate steel for strength at the specific points where the force acts.


Figure 13.20. Close-Up of Drive Mechanism.


HEAT EXCHANGER TO PREVENT OR REDUCE EFFECTS OF EXERCISE-INDUCED ASTHMA

Student Designers: Victor Kosmopoulos, Aaron Mason, Matthew Torniainen Supervising Professor: Joseph C. Mollendorf, Ph.D. Mechanical and Aerospace Engineering Department


INTRODUCTION A temporary increase in airway resistance for several minutes after a person has stopped strenuous exer-cise is referred to as exercise-induced asthma (EIA). Approximately 12% to 15% of the general population is believed to suffer from EIA at some point during life. The exact causes of EIA are not entirely known, although several hypotheses exist. Primary agitators include cooling of the airway, water loss, and the temperature gradient. Currently, there are many pharmacological methods of dealing with EIA, but few non-pharmacological alternatives. Suggested non-pharmacological means to reduce this problem include warm-ups and cool-downs before and after exercise, continuous physical exertion, and warm, humidified air. Since the effectiveness of warm-ups and cool-downs varies and since continuous physi-cal activity is not always possible or desired, the ob-jective of this project was to design a device that warms and humidifies inspired air.

The device consists of two basic components, a breathing mask and a plastic tube used as a heat ex-changer. Air is breathed from the end of the tube and into the breathing mask. As the air travels to the mouth, it is warmed by body heat and moistened through small holes in the tubing. With this device one who suffers from EIA can reduce or even elimi-nate the effects after exercise has ceased.

SUMMARY OF IMPACT This inexpensive, reliable heat-exchanging mask al-lows people who suffer from EIA an alternative to pharmacological methods. This mask is simple to wear and durable for use during various exercises. Although the aesthetics are not pleasing, its weight is minimal.

TECHNICAL DESCRIPTION The goals of the design were to produce a heat- ex-changing device, which would be inexpensive, light-weight, reliable, durable, easy to assemble and strap on, safe, efficient, and aesthetically pleasing. The de-sign began as a counter-flow heat-exchanging me-chanical device. That design led to an electrical coil heating device and finally the simple device seen in Figure 13.21.

Heating and moisturizing of the air, while still allow-ing for a flow rate not restricting to the body, were of major concern. Due to the power required to achieve this temperature gradient, an unacceptably heavy bat-tery pack would be necessary for the counter flow heat exchanger and the electrical coil heater.

The current device is strapped to the body under-neath the clothing. During exercise the body pro-duces heat and perspiration as it attempts to achieve equilibrium. The body acts as a heat exchanger when inhaled cold air travels through the respiratory sys-tem and is exhaled as warmer air. The device utilizes the work of the body to heat the inspired air. The small holes in the tubing allow moisturizing of in-spired air, as the holes are near the moist body when the device is strapped in place. The tubing also facili-tates maintaining moisture from the exhaled air for the next breath of inhaled air. All goals of the design, except aesthetics, were achieved with this device.



Figure 13.21. Breathing Mask and Tube Heat Exchanger.


UTENSIL HOLDER HAND BRACE Student Designers: Juyeun Yoo



INTRODUCTION Hand injuries or chronic hand conditions can impair the ability to pinch or articulate fingers. Patients may have pain while grasping utensils, or may be incapa-ble of holding utensils.

A prototype was designed to enable a person with limited use of his/her hands to hold with stability ordinary utensils such as a spoon, fork, razor, knife, or pen.

SUMMARY OF IMPACT The Utensil Holder Hand Brace assists patients with chronic or temporary hand conditions with tasks such as eating, writing, or hygiene. This design re-lieves pain from imposing pressure to the utensils and thus helps patients use the implements, even when unable to coordinate their fingers.

Most ordinary utensils fit into the Utensil Holder Hand Brace, thereby eliminating the need to spend money on expensive, custom-made utensils. Fur-thermore, the brace is easily maintained and easily slips onto a person’s hand.

TECHNICAL DESCRIPTION During creation this design, the basic hand shape and its kinematics were studied by observing differ-ent hand positions of persons holding various im-plements.

In building the prototype, the selected materials were Aquaplast and Polyform. The advantageous features of the material properties are shown in the Table 13.3.

Properties Description

Heating Time 150°F to 160°F water immersion for 1 minute.

Molding Material not required to be very hot, permitting direct placement in patient’s hand. Three to five min-utes working time.

Bond Ability For permanent bond, pinch heated surfaces together.

Table 13.3: Properties of Aquaplast and Polyform

The design of the utensil Holder Hand Brace was di-vided into the following segments: the holder, the ver-tical interface, the horizontal interface, and the hand piece.

The hand piece was made with Polyform, while the remaining components were made with Aquaplast.

Individuals with different hand sizes tested and evaluated the finished model and reported that it fit comfortably. The brace can hold objects of uniform thickness of 0.5 cm to 1.5 cm. Utensils neither move nor detach while undergoing a task.



Figure 13.22. Utensil Holder Hand Brace with Pen and Knife.

173

CHAPTER 14 TEXAS A&M UNIVERSITY

College of Engineering Bioengineering Program

College Station, TX 77843


William A. Hyman (409) 845-5532 [email protected]


OPTIMIZATION OF ENVIRONMENTAL CONTROL TO FIT A SMALL LIVING SPACE

Designer: Maxim Eckmann Client: Russel Rawlings

Student, Texas A&M University Supervising Professor: W.A. Hyman

Biomedical Engineering Program Texas A&M University

College Station, Texas 77843

INTRODUCTION An Infrared Point and Click subsystem was designed as a low cost environmental control system (ECS) in-tended for people with disabilities in a dormitory room. ECSs enable improved access to appliances and other environmental assets in their homes. The systems must be able to accept many forms of input from devices, such as sip/puff switches or push but-tons, and translate this input into many different forms of output.

Most ECSs are not optimized for the dormitory room environment; they have inappropriate functions that can be wasted. This waste reduces their cost effec-tiveness. Currently, the price of fully functional ECSs ranges from $1000 - $6000. Reduction of cost and op-timization of environmental control in small living spaces (like a dormitory) would make ECSs more available to and practical for college students.

SUMMARY OF IMPACT The adaptation of home automation for people with disabilities has greatly improved the accessibility in the home environment. The modern ECS has become sophisticated and is able to provide a large range of environmental controls and flexibility for users.

The current ECS appears to have the capability to adapt to any situation and almost any user. Almost complete control over appliances can be achieved. It would be possible to use all available functions in a house, but full functionality would not realistically be achieved in a small one-room environment.

The components of the Infrared Point and Click sys-tem were built and laboratory tested. The client did

not return to school. Thus, the subsystem remains untested in the field.

TECHNICAL DESCRIPTION OUTPUT METHOD: THE IR RECEIVERS A standard remote control, the Joystick TV Remote Control (detailed later), or a simple IR transmitter may be used to activate the receiver. A simple IR transmit-ter, designed with the client's abilities in mind, was built for use with the receivers. It features a 15-pin connector similar to those found on many joysticks. A schematic is shown in Figure 14.1.

This circuit uses 555 TTL IC’s (timer chips). In com-bination with the correct resistor and capacitor val-ues, the three 555 timers create square wave oscillator circuits at the desired frequencies. R1 is connected to pins 7 and 8 on the 555 timer IC. R2 is connected to pins 7 and 2. C is connected to pin 2 and ground. In-creasing R2 in comparison to R1 makes the duty cycle even. R1 should not be less than 1kΩ .

One 555 timer drives the infrared emitting diode. Its fundamental frequency must be 38 kHz for the opti-mal response in the IR receivers. The timer can be ac-tivated directly with pin 14, resulting in a positive output from an IR detector module in a receiver. Acti-vation of pin 14 issues one command.

The other two 555 timers oscillate at approximately 2 kHz and 5 kHz. These timers drive the main 38 kHz timer, creating 2 and 5 kHz bursts of the 38 kHz sig-nal. In an IR detector module, this produces square waves at 2 and 5 kHz, corresponding to two addi-tional commands.

Chapter 14: Texas A& M University 175

A lever style switch was built for the transmitter. Pulling on the lever results in an emission of a 38 kHz square wave IR signal. The control switches plug into the 15 D connector. Power is bridged by the switches through the transmitter's 6.5-volt battery pack (4 AA batteries), to pins 3, 6, and 14. Simple push buttons may be used as the switches, but there are many options that could potentially be used. The switch must use a 15 D connector and have the ap-propriate pin connections as given in this design to activate the transmitter.

The system uses a network of simple IR activated power relays. This provides control over lamps, on/off type appliances and the thermostat setback module.

Circuitry in the receiver stores the current state of the device. When a strong IR signal at the proper fre-

quency is detected, the state is toggled. Toggling of the state also toggles a 5-volt relay, the contacts for which are rated for an amount of power sufficient for the appliance. The relay bridges a connection be-tween the wall outlet and the appliance that is plugged into the receiver.

Figure 14.2 shows an electrical schematic for the IR receiver. The entire system is designed to run be-tween 5 and 6.5 volts, optimally. This voltage is pro-vided by a DC power source that plugs into a jack on the receiver. Note that the output from the IR detector module must be run through an inverter (74LS04), since it is originally active low. A 555 timer IC is used to create an oscillating square wave, serving as the clock. In this case, a NE556N (dual) timer IC was used because it was readily available. The IR detector module is a standard component, part #276-137, available from Radioshack. It measures approxi-

555

78

6

2

R047E4

R11E3

C31E-9F

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555

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R11E3

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D3Optional

Dip Pin 14

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5 kHz 2 kHz

D_IRInfrared

DIP Socket3

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1

7 8

14

1

3

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5

6

8

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12

14

15+6.5V

+6.5V

+6.5V

15 DConnector

Figure 14.1. Schematic of a Simple, Thee-Command IR transmitter.


mately 1.5 x 1.5 x 1 cm. Circuitry in the detector has a band-pass response of 38 kHz. The IR detector can recognize signals from the Switch Activated IR transmitter, or any standard remote control. The out-put of the detector is connected to pin 11 of the in-verter (74LS04), since it is active low and a high out-put is required to toggle the J-K latch.

The detector module is so sensitive that the operation of a TV remote control can trigger a receiver as far away as 15 feet. Therefore, optical obstruction of the receiver with a 0.5 mm thick piece of opaque material (such as aluminum or plastic) is employed to reduce sensitivity. When a remote control is within 3 feet of the receiver, toggling of the relay is effective. Direc-tion has an effect on selection as well, as the optical signal strength attenuates with increasing angle. Thus, both proximity and direction are employed to perform selection and activation simultaneously.

A J-K latch (74LS76) stores the state of the receiver. The latch receives a clock from the NE556N timer. If there is a DC signal at pin 4 of the latch during an upward clock transition, the state of the latch output

(pin 14) will change. The state output of the latch, pin 14, is used to activate/deactivate the magnetic switch in the relay. The signal is first passed through the hex inverter to buffer the signal. Current loading on the 74LS76 output may result in instability in the state.

A typical NPN transistor is used as a simple current driver; the TTL components are not able to provide enough current for some of the larger relays. The re-lay interrupts the power to one prong in a 3-prong adapter. The controlled appliance plugs into the adapter, which is then plugged into the wall. The re-ceiver is connected to this adapter by a cable.

JOYSTICK TV REMOTE CONTROL The Joystick TV Remote Control is a device modifica-tion of an existing programmable remote control. The main function buttons (power, volume, channel) on a One For ALL remote control are connected via rib-bon cable to a digital joystick. Some users with physical disabilities can use this improved joystick interface instead of the smaller buttons on the regular remote control, which are often difficult to manipu-

5

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1CLK

Vcc

Vcc

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98

8

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1 kOhm

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0.1 uF

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74LS76

NE556N

8 9

10

11

141

2

74LS04

IR DetectorModule

IRSignal

Vcc

Coil

120 V AC

IR Receiver Schematic

Figure 14.2. Electric Wiring Diagram of a Toggling Relay Circuit that Responds to IR Input.


late. Design specifics for this modification are avail-able from Dr. William Hyman, Biomedical Engineer-ing Program Chair at Texas A&M University. Materi-als used in the construction of this device cost ap-proximately $50.

INTEGRATION WITH OTHER SUBSYSTEMS Integration of the Infared Point and Click subsystem with other subsystems can provide most functions re-quested by the client. This system currently provides no definite solution for light switches. The basic re-ceiver could be used to interrupt the light switch cir-cuit. Otherwise, lighting can be controlled through the on/off toggling of lamps plugged into the receiv-ers. Temperature control is also available. Use of the Joystick TV Remote Control, existing garage door openers, and an RC100 or RC200 telephone provide the other functions requested by the client. Figure 14.3 shows the block diagram of this integrated sys-tem.

One function that cannot yet be implemented is con-trol over the blinds. A modified receiver must be de-signed for this control option. The state output of the latch can be tied to reversed relays that alternately supply power in one direction or another to a motor in the presence of an incoming signal. Latch output and IR detector output would be ANDed together with an AND IC at the connection to each separate re-lay magnet. The motor, with appropriate interface and gearing, could then be used to open or close the blinds.

DISADVANTAGES If a switch-controlled telephone is used, assistance is required to obtain the switch. Also, while depression of almost any button on a standard TV remote control can activate a receiver, use of the remote control on the receiver could inadvertently affect the television. Blind control, the least important function on the cli-ent's list, is not currently available.

The receivers' designs do not include an onboard power supply that can harness the needed current

from the incoming AC power. While a simple power supply could be implemented, the current design uses a 6V DC power supply that must occupy its own out-let. If there were a shortage of outlets, power strips would need to be purchased.

ADVANTAGES The system has eliminated complex centralized con-trol at a tremendous savings in cost. Each receiver's materials cost is approximately $25. This cost could be reduced by the integration of an onboard power supply.

The material cost of this system is $650. This in-cludes 8 receivers, 8 power supplies, 2 power strips, the Joystick TV Remote Control, and the RC200 phone. The telephone comprises the majority of the cost ($400).

Integrated System with IR Point and Click Control

StandardRemoteControl

38 kHzIR Emitter

Buttonw/ 15 D

Connector

IR ReceiverRelay

IR ReceiverRelay

Appliancesand

Lamps

LightSwitchesNot yet supported

ThermostatSetback

Controller

IR ReceiverRelayNot yet supported

TelevisionJoystick TV

RemoteControl

Voice orSwitch

2 GarageDoor

Controllers

SpecializedTelephone

PoweredDoor

Openers

Stationary Mobile

Figure 14.3. Environmental Control System.


AN ARM BRACE FOR USE BY PATIENTS WITH LOWER BACK TROUBLE

Designers: Price Bradshaw III and Robert Meltzer Client: Nicholas Cram, Director of Bioengineering

St. Joseph's Medical Center Supervising Professor: W.A. Hyman



INTRODUCTION An arm brace was designed for a patient who had re-cently undergone lower back surgery and required support of the right arm. The brace is composed of three components: a lower back support, a lower arm support band, and an extendable rod attached to a pair of universal joints (Figure 14.4). The device is light, reasonably comfortable, and easily secured.

SUMMARY OF IMPACT The client was a dentist who had recently undergone lower back surgery. The nature of his work requires long periods of time spent with his arms extended, causing lower back strain. The device reduces this strain by transferring the weight of the arm directly to the hips and legs. The design of the brace includes a set of steel rods that extend from the right arm to a back support belt worn around the waist. This de-sign successfully reduces strain in the lower back.

TECHNICAL DESCRIPTION The brace was designed for a specific patient but could be used for a number of individuals. The de-sign requirements for the arm brace were that it: 1) re-lieve the strain on the lower back caused by the exten-sion of the arm; 2) allow unrestricted range of motion of the arm; and 3) be lightweight and comfortable.

The arm brace is made of a standard lower back sup-port belt, a lower arm brace similar to those used for tennis elbow, a hollow steel rod, a threaded steel rod, a nut, two cotter pins, and two universal joints. One universal joint is riveted to the outside of the back support belt on the right side. A cotter pin attaches a 12” hollow outer rod with a 0.5” inner diameter to

this joint. A 0.5" nut is attached to a 0.5" threaded rod, 14” in length, to act as a stopcock. The nut can be used to change the length of the supporting brace by rotating it clockwise or counterclockwise. The threaded rod and attached nut are inserted into the hollow rod. The free end of the threaded rod is riv-eted to the lower arm support to complete the assem-bly (Figure 14.5).

The pair of universal joints at either end of the rods allows an almost unrestricted range of motion. The maximum extension distance of the rods is 26" and the minimum is 14". The device design is effective but the lower arm brace can reduce circulation if it is ap-plied improperly or worn for extended periods of time.

The approximate cost of the arm brace is $45.00.

Figure 14.4. Completed Arm Brace


Back support beltvelcro closurewith lumbar support pad

Steel rod

2 X universal jointsconnected with cotter pins

Arm braceattached to jointwith pop rivets

Figure 14.5. Arm Brace Assembly.


AUGMENTATIVE COMMUNICATION DEVICE Designers: Gretchen Meyer and Emily Stephenson

Client Coordinator: Mrs. Peddicord Music Therapist, Bryan Independent School District

Supervising Professor: W.A. Hyman Biomedical Engineering Program

Texas A&M University College Station, Texas 77843

INTRODUCTION Augmentative communication devices are used in many school and therapy settings with students who have few or no speech capabilities. These devices provide a means for students to express themselves and to receive audio feedback corresponding to spe-cific commands they have selected. An augmentative communication device can be defined according to the number of cells, or individual selections, the de-vice provides. These cells are associated with a spe-cific symbol or command. Each individual cell can be attached to an access mechanism that facilitates the audio feedback. The number and size of cells re-quired is dependent on an individual’s cognitive and motor abilities.

There are many different ways a user can access the system. These include touch, a remote switch, a scanning system, auditory scanning, and optical pointing. Finally, a digitized or synthesized speech recording and playback device must be integrated.

This project incorporated multiple remote switching devices (Figure 14.6). Four digital voice recorders, manufactured by Marlin P. Jones and Associates, were adapted for AC power. Each recorder used in this device can hold 10 seconds of speech.

SUMMARY OF IMPACT Two augmentative communication devices were de-signed for specific students, but can each be adapted for various users. The first device was intended for a seven-year-old boy with autism. He had minimal speech capabilities and could not communicate with his teacher. He had been using a device, designed by his teacher, that consisted of a large piece of paper with pushpins. Various objects were suspended on the pushpins to communicate when he wanted to

swing, color, eat, use the restroom, etc. The device did not provide auditory feedback.

Digital voice recorders were used to design an aug-mentative communication device with four cells. Each cell, consisting of a remote switch, has a picture that represents something the child might want to ex-press. When the switch is activated, the speaker plays a verbal message that corresponds to the stu-dent’s choice. The device gives the student a way to communicate and provides auditory feedback to fa-cilitate his speech development.

The second device was designed for a four-year-old boy with De George’s Syndrome, a disease that affects the immune system. Due to his weak immune system, this child had no interaction with anyone but his parents and doctors for the first three years of his life. This lack of interaction with others has severely af-fected his communication skills. A device similar to the first was used with primary design alterations in the cell specifications and the recorded speech.

Figure 14.6. Augmentative Communication Device


TECHNICAL DESCRIPTION Each voice recorder was originally designed for bat-tery (DC) power. Since the voice recorder continually uses power to maintain memory, the batteries die within two weeks. To resolve this problem, the four recorders have been converted to AC power by con-necting each in parallel to an AC/DC adapter (Fig14.7). The device can now use AC power from a wall socket and retain memory as long as it is plugged in.

Each voice recorder was purchased with a standard play switch built into the mechanism. Record switches are added using momentary push button switches. After the recorders were adapted they were enclosed in a 15.5" x 8" x 1.75" wooden box.

The total cost of each device is approximately $60.

PlaySwitch

RecordSwitch

PlaySwitch

RecordSwitch

PlaySwitch

RecordSwitch

PlaySwitch

RecordSwitch

AC/DC4.5/6 VDC

AdapterDCPowerJack

Figure 14.7. Device Configuration.


CLOTHES DRYER WITH FRONT MOUNTED CONTROLS FOR HANDICAPPED ACCESS

Designers: Jon Berkovich and Chris Stamper Supervising Professor: W.A. Hyman



INTRODUCTION A clothes dryer was adapted to make the task of do-ing laundry simpler for people who use wheelchairs (Fig. 14.8). The design of the device is simple. The ex-ternal control panel for the dryer was moved from the back to the front of the dryer and mounted with metal clamps. The internal wires were lengthened and a rectangular section of the dryer cover was removed to allow the wires to reach the controls. The dryer model was equipped with a front lint catcher, allow-ing the device to be used without external assistance.

SUMMARY OF IMPACT Moving the dryer controls from the back to the front of the appliance enables wheelchair users to more easily dry their laundry.

TECHNICAL DESCRIPTION The design requirements for the dryer were that it: 1) have a front lint catcher; and 2) have controls that are accessible from a seated position.

A GE model DDE 7500VALWH, serial number VA2 1 7 4 1 6 G, was used in this design. A 20" x 2" rectangular portion was removed from the front of the top cover of the dryer to provide space for the wires to reach the control panel. Each wire was lengthened by 6" using 150ºC, 12-guage electrical wire. Fourteen 16-guage male/female adapters were used to connect the existing wires with the new additions. Standard elec-trical tape insulated all wires exposed to the thermal environment of the dryer. Finally, two 2" oval stainless steel clamps were attached to each side of the dryer lid to ensure that the cover remained se-curely fastened.

The cost of the modified dryer was $160.


Figure 14.8. Front Mounted Dryer Controls.


ADAPTED SEE’N’SAY FOR CHILDREN WITH LIMITED DEXTERITY

Designers: Price Bradshaw and Rosalyn Metcalfe Supervising Professor: W.A. Hyman



INTRODUCTION Children with limited dexterity often have difficulty operating toys such as the See’n’Say, which require physical manipulation. Because the See’n’Say is op-erated by pulling a lever, it requires both strength and dexterity. This toy was adapted by connecting a push button to a circuit to activate the lever (Figure 14.9).

SUMMARY OF IMPACT The design was successful in allowing a child with poor dexterity to operate a See’n’Say with ease. Due to design limitations, the recordings were not played in full. Using a longer connecting chain may rectify this problem. In addition, the modified toy is not eas-ily portable because the wood base is too heavy and bulky for a small child. This design is the first step towards a workable solution.

TECHNICAL DESCRIPTION A ratchet and an industrial-strength circular fan mo-tor were wired into a timing device activated by a push button. The See’n’Say lever was connected to the motor and ratchet with 1/8” brass safety chain. A

sprocket type ratchet system was used to allow only unidirectional rotation. The timing device, referred to as a “one shot,” is commercially available from IDEC Industries. The device was used to engage the motor for approximately two seconds.

During the two seconds, the motor rotates, pulling the lever of the toy downward, providing energy for the operation of the toy. After two seconds the motor stops rotating and the lever returns to its initial posi-tion, allowing the See’n’Say recording to be played.

The See’n’Say is elevated on a 4” x 4” wood block to allow the lever to clear the ratchet. The entire system is mounted on ¾” plywood with L brackets.


Figure14.9. Adapted See’n’Say.

187

CHAPTER 15 UNIVERSITY OF ALABAMA AT

BIRMINGHAM Department of Materials and Mechanical Engineering

BEC 254, 1150 10th Ave. S. Birmingham, Alabama, 35294-4461


Alan W. Eberhardt (205) 934-8464 [email protected]


SHOWER CHAIRS FOR INDIVIDUALS WITH CEREBRAL PALSY

Designers: 1998 Mechanical Engineering and Materials Science Senior Design Students Client Coordinators: Dr. Gary Edwards, United Cerebral Palsy of Birmingham

Supervising Professors: Drs. Alan Eberhardt, B.J. Stephens, Laura Vogtle* Department of Materials and Mechanical Engineering

*Division of Occupational Therapy University of Alabama at Birmingham

Birmingham, AL 35294-4461

INTRODUCTION Shower chairs currently on the market have failed to meet the needs of clients with cerebral palsy and their caregivers. Shortcomings include:

• Frames too weak for heavier clients, failing with repeated use;

• Mesh backing uncomfortable and abrasive to skin;

• Castors prone to rust, restricting mobility;

• Users’ arms and legs protrude and catch in open sides;

• Clients may slide off seat; and

• Cleaning difficult due to low seat height.

Three different shower chairs were developed for three clients with varying conditions of cerebral palsy:

• an elderly man weighing approximately 300 pounds;

• a thin man with severe kyphosis of the up-per spine, fused spinal segments in his lower spine, and knee flexion contractures; and

• a young woman, weighing less than 100 pounds, having severe curvature of the spine and spasticity of the arms and legs.

Many issues are considered in the design of the chairs, including durability, comfort and safety.

TECHNICAL DESCRIPTION PRELIMINARY DESIGN The preliminary design establishes the foundation for the specific designs by focusing on the following five major areas: the structural frame, adjustability, mo-bility, seating, and safety. The material for the frame was AISI-Type 304, satin-finish stainless steel thin walled tubing that meets the requirements for high strength, low weight, corrosion resistance, and aes-thetics. The frame components are joined by gas ar-gon arc welding, according to specification AWS WP1-01. Certified contractors performed all tube bending and welding. The preliminary chair design is shown schematically in Figure 15.1. This struc-tural configuration was analyzed using Caesar II fi-nite element software (Algor Inc., Pittsburgh, PA) for a distributed load representing a reclined 300-pound person. All frame members and joints yield safety fac-tors greater than two. The 32.5-inch seat height makes cleaning easier for the caregiver.

There are two large solid rubber wheels in the rear and two smaller swivel type casters in the front to make the chair mobile. The brake-type casters are 4 inches in diameter and 1.5 inches in width, designed for a maximum 250-pound load. The metal compo-nents of the rear wheels and the front casters are stainless steel, ensuring durability and corrosion resistance.

Chapter 15: University of Alabama at Birmingham 189

A support arm attached to the backrest establishes the angled position of the backrest, which fits into two slotted sidebars (Figure 15.1). For the seat adjustment there is a prop-hinge installed under the seat on each side. To adjust the seat upwardly, a second horizon-tal support bar fits into two slotted sidebars attached to the front frame. There is a handle beneath the seat, enabling the caregiver to easily adjust the seat rest. The leg rest rotates outward and locks with a posi-tioning pin placed through pre-drilled holes.

Swing-away armrests provide easy transfer of the cli-ents into and out of the shower chair. A 1.5" diameter piece of tubing is welded to each side in the middle

near the base to act as a pivot. Another tube is welded to the front side of the chair to act as a har-ness for the swing-away armrest. The armrest is ro-tated by lifting it from the harness and swinging it toward the rear of the chair.

Fringe is welded to the bottom of the pivoting section to prevent the armrest from coming completely out of the rear tube. The armrests are fitted with padded side panels to keep the clients' arms from tangling during transport into and out of the chair. The foot-rest is designed to pivot from the leg rest as a solid piece, allowing the footrest to remain with the leg rest

22.00"

28.00"

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ITEMNO.

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M-06M-07M-08M-09M-10M-11

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1" DIA -12 GAUGE TUBE1" DIA -12 GAUGE TUBE1/4" THICK PLATE1/4" x 1 1/2" BAR1" DIA -12 GAUGE TUBE (39" LENGTH)1" DIA -12 GAUGE TUBE (18 3/4" LENGTH)1" DIA -12 GAUGE TUBE (22" LENGTH)1 1/4" DIA - 12 GAUGE TEEPADDED SEAT BELT1/4" x 1 1/2" BARPADDED SEAT24" DIA WHEEL4" SWIVEL LOCKING CASTERHANDGRIPBACK FRAME ASSEMBLY1 1/4" DIA TUBE (2.5" LENGTH)LEG REST ADJUSTMENT PLATELEG REST ADJ. PLATE (SEAT ATTACHEMNT)LEG REST HINGE ASSEMBLYLEG REST ASSEMBLYSEAT ADJUSTMENT ROD ASSEMBLYBACK ADJUSTMENT ROD ASSEMBLYARM REST FRAMEARM REST PAD3/8" DIA SOLID ROD, BENT AND COVERED3/8" DIA SOLID ROD, (24" LENGTH)COVERING MATERIAL FOR BACK FRAMECOVERING MATERIAL FOR LEGRESTSEAT FRAME ASSEMBLYFOOT REST ASSEMBLY

DESCRIPTION MAT'L

304 SS

RUBBER

NYLON

FOAM

GEL FOAM

FOAM

CLOTHCLOTH

304 SS304 SS304 SS304 SS304 SS304 SS304 SS

304 SS304 SS304 SS304 SS304 SS304 SS304 SS304 SS

304 SS

304 SS

304 SS

304 SS304 SS

304 SS304 SS

QTY.

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15

14

12

26

9

7

8

23 25

11

29

14

27

12

3

22

4

16

2 24

11 17

19

18

2028

30

13

25

5

10

16216

1

15

50.50"

35.25"32.50"

38.50"

23

24

Figure 15.1. Schematic of the Preliminary Chair Design.


in any position. The one-piece construction prevents the clients' feet from becoming entangled.

Since the clients’ skin comes in direct contact with the chair back and seat, comfort is extremely important. The backrest is made of awning material, which is soft to the touch, waterproof and durable. A clip-on padded toilet seat is use. It is durable yet comfortable, and allows easy access to the groin area for the care-giver. The clip-on feature allows it to be rotated 90 or 180 degrees for custom fitting.

A seatbelt is attached. Its locking device is located on the side of the chair frame to minimize discomfort. A pad attached to the belt prevents abrasion. A basket is attached to the backrest for storage of bathing items.

SHOWER CHAIR #1 Design Students: Robert Cooner, Leah Hardy, Dierdre Jackson, Lee Motes, Rafael Nunez, Otha Richardson, Sharron William-

son, Eddie Saunier

SUMMARY OF IMPACT This shower chair was designed for a thin, frail man with cerebral palsy. He weighs approximately 65 pounds. He has restricted hip flexion due to fusion of sacral and lumbar vertebrae, severe kyphosis of the cervical spine, and knee flexion contractures (45-60 degrees flexion). This chair enables him to shower without the fear of falling out of the chair and without pain. Unlike before, he is able to remain in the shower long enough to allow for appropriate hygiene.

TECHNICAL DESCRIPTION The primary design concerns were adjustability and comfort in both inclined and reclined positions. The client is extremely susceptible to pressure sores, so special attention was paid to seat and backing mate-rials. Adjustability of the seat backing was achieved via tie-strings that secure the backing to the frame and

allow the backing to be loosened or tightened as de-sired to contour with the client’s back. The footrest is constructed of a stainless steel plate, attached to the leg rest. The foot and leg rest are attached directly to the seat so that they move with it, maintaining the de-sired angle. The toilet seat substrate is an open back, vinyl injection molded material clamped onto the seat frame. The square seat was sized to be 18.375 square inches because of complaints that the previous 21-inch seat was oversized. This was overlaid with an inflatable seat cushion (RoHO Inc., Belleview, IL) to provide increased comfort. The center hole has an 8-inch circumference for access.

The total cost of this shower chair is $1205.27. This includes $805 for parts and $360 for fabrication.

Figure 15.2. Shower Chair.


SHOWER CHAIR #2 Design Students: Michael Ball, Tina Childress, Michael Gordon, Jana Jenkins, Kristi McLain, Mitch Mansfield, Darin Odom,

Tom Young

SUMMARY OF IMPACT This shower chair was designed for a 300 lb. man with cerebral palsy, mental retardation and partial blindness. Previously purchased commercial shower chairs were unable to support his weight and had failed in service. As a result, he was usually bathed in his wheelchair. This shower chair will extend the life of his wheelchair by providing an appropriate shower medium.

TECHNICAL DESCRIPTION In this design, specific areas of focus included the structural framework, ease of patient transfer from wheelchair to shower chair, comfort and safety. The client is above average in size, so the chair dimen-

sions are larger and the frame is made to support more weight than the average shower chair. To in-crease ease of transfer, the seat height of the chair is near the height of his wheelchair seat (approximately 26 inches). This structural configuration was ana-lyzed using Caesar II finite element software (Algor Inc., Pittsburgh, PA) for a distributed load of 1000 pounds, representing a worst case dynamic loading. All frame members and joints yield safety factors greater than two.

The total cost of this shower chair was $1,436.27. This includes $1028.11 for parts and $436.16 for fab-rication.

SHOWER CHAIR #3 Design Students: Shane Wolfe, Jeremy Wolfe, Jim Gaydon, Jana Jenkins, Lee Motes, Jeff Gordon, Mitch Mansfield

SUMMARY OF IMPACT This chair was designed for a young woman with se-vere cerebral palsy. Specific design issues in this case included comfort for her severely curved spine and prevention of her arm and legs extending beyond the chair, which has been problematic due to spasticity in her arms and legs. The completed chair relieves pain previously experienced by the due to ill-fitting equipment.

TECHNICAL DESCRIPTION The preliminary design met the basic requirements, with minor modifications. The height of the seat back

was extended to allow for head support in reclined positions. An 18 3/8" square-shaped, open front, padded seat was used. The seat is equipped with clips so that it can be easily removed, rotated, and re-positioned, allowing the caregiver to optimally orient the opening to accommodate the client’s spinal curva-ture.

The total cost of this shower chair was $1,500.57. This includes $798.57 for parts and $702 for fabrica-tion.


FOREARM MOTION/TORQUE ANALYZER Student: Michael Wheatley

Project Coordinators: Drs. Stephanie Delucas1, Edward Taub2 1Spain Rehabilitation Center, 2Department of Psychology

Supervising Professors: Drs. Alan Eberhardt, Martin Crawford, Evangelos Eleftheriou Department of Materials and Mechanical Engineering

University of Alabama at Birmingham Birmingham, AL 35294-4461

INTRODUCTION A forearm motion/torque analyzer was designed for patients recovering from strokes. It consists of a pad-ded arm support and a grip that is moved through pronation and supination of the forearm. Torque and rotational motion are visually displayed on needle gauges, permitting the evaluator a convenient meas-ure of relative improvement in wrist and forearm strength and range of motion. The guages also pro-vide visual feedback to the patient during rehabilita-tion therapy.

SUMMARY OF IMPACT Strokes may affect a person’s control of the muscu-loskeletal system and abilities to perform skilled be-haviors. There is a need for a therapeutic wrist mo-tion/torque analyzer to allow stroke victims and evaluators to observe supination and pronation mo-tor skills during rehabilitation. It also provides for limb isolation, variable resistance, comfort and versa-tility.

TECHNICAL DESCRIPTION The motion/torque analyzer consists of a padded arm support, a mobile grip, a box housing spring and damper resistance, and needle gauges for measure-ment of torque and rotation (Figure 15.3). The padded armrest is attached to the device by a latch on each side, facilitating storage and contributing to the mo-bility of the device.

The device restrains the patient's arm with adjustable nylon D-ring straps to prevent the use of the shoulder in rotation of the affected limb. A special set of gloves allows the patients' hands to be secured in a "gripped" position. The hand grip is configured to al-low ambidextrous finger positioning. Since the de-vice is to be used in a medical environment, all exte-

rior surfaces are non-absorbent and capable of with-standing repeated cleanings.

The grip is attached directly to a rack and pinion sys-tem that converts the rotational motion induced by the patient into linear motion. Two extension damp-ers are attached to the rack gear, one on each end (Figure 15.4). The stroke length of the cylinders was chosen so that a 170-degree rotation of the pinion gear does not exceed the stroke length of the cylin-ders. The hydraulic dampers increase or decrease the amount of resistance to motion in response to the rate at which they are deformed. The amount of resistance is a direct function of the rate at which the patient ro-tates his or her forearm. Additionally, the dampers do not increase resistance at range of motion ex-tremes. Instead, as the patient reaches the extreme, by reducing the rate of rotation, the resistance offered by the damper decreases. As the patient's motor skills improve, the resistance may be increased proportion-ally to the rate of rotation. The length of the rack gear is sufficient to accommodate 85 degrees of rotation in either direction. As a safety measure, the tooth spaces on the rack gear corresponding to range of motion ex-tremes are filled with epoxy.

Range of motion is measured directly from the shaft of the pinion gear, which is also the shaft to which the grip is attached. On the exterior of the device, a nee-dle attached to the shaft indicates the degrees through which the shaft is rotated (Figure 15.4). Two addi-tional needles attached to, but independent of, the shaft are used to indicate the maximum degree of ro-tation in both directions. The torque is measured ac-cording to the resistance offered by the damper. Since the diameter of the pinion gear is known, the torque will be the product of the damper force and the pitch radius of the gear. The damper force is measured by an extension spring attached in series to each of the


two dampers. The dampers are threaded into the rack gear on one end. The other end of the damper is threaded into an adjustable turnbuckle that attaches to the spring through an eyebolt. Pins passing through each of the adjustable turnbuckles indicate the displacement of the spring to torque gauges mounted on the exterior of the device. An indicator needle on the exterior of the device attached to the pin moves linearly as force is applied to the spring. It in-dicates the torque the patient is applying according to a calibrated scale on the exterior of the device. A sec-ond freely moving needle, not attached to the spring,

indicates the maximum torque applied. The same apparatus is used on both springs so that the torque may be measured in both directions. The adjustable turnbuckles allow the use of different springs and dampers to accommodate patients who are excep-tionally stronger (or weaker) than the average patient.

The total cost of the wrist motion/torque analyzer was $420.61. This includes $176.61 for parts and $244 for fabrication.

Figure 15.3. Wrist Motion/Torque Measuring Device.

Figure 15.4. Rack and Pinion, Hydraulic Cylinders, and Needle Gage Attachments.


WHEELCHAIR HEADREST DESIGN Designer: Aaron T. Joy

Client Coordinators: Dr. Gary Edwards, United Cerebral Palsy of Birmingham Supervising Professors: Drs. Alan Eberhardt, Martin Crawford, Laura Vogtle*

Department of Materials and Mechanical Engineering *Division of Occupational Therapy

University of Alabama at Birmingham Birmingham, AL 35294-4461

INTRODUCTION: A headrest was designed for a woman with cerebral palsy. It restricts movement of her head to the left, prohibits her chin from dropping, and offers support to her head and neck. The device is constructed using commercially available hardware and is custom fitted to the client's head, providing comfort and cosmetic integrity. A detachable forehead strap is fitted to the device to provide additional support and prevent forward movement.

SUMMARY OF IMPACT The head rest/support system is for a woman with cerebral palsy. The device allows her prolonged, ac-curate use of her augmentative communication device and facilitates eating and swallowing. The design provides comfortable support for extended periods of time throughout the day, with a detachable forehead strap that may be used when she is tired.

TECHNICAL DESCRIPTION Previous designs were not durable and had insuffi-cient infrastructure. They did not support the client’s chin and jaw, which tend to drop as she tired. Her previous headrest also interfered with her eyeglasses and the infrared sensor used for her voice activation board.

Initially, a negative mold was made of the client’s head and neck using plaster casting for subsequent fitting of components. From the negative mold, a positive mold was constructed for use in subsequent development. For the purpose of structural frame and attachment design, lateral and dorsal head forces were measured using a bathroom scale.

Rather than developing new components, commercial components were customized to minimize costs. The Whitmyer SOFT-1D (Whitmyer Biomechanix, Inc.,

Tallahassee, FL) was purchased because it met the criterion for chin support. It consists of left and right sub-occipital pads contoured to cradle the client’s chin from ear to ear. One-half to one-inch clearance was allowed for lateral and vertical movement, while inhibiting movement to the left and cradling her chin.

The device was constructed of 14 gauge carbon steel plate, covered by closed-cell polyethylene foam and by water resistant Lycra that is soft to the touch. The occipital pad was reduced in size relative to the cli-ent’s previous headrest to decrease interference with her eyeglasses during movement. The pad is pre-

Figure 15.5. Headrest for Woman with Cerebral Palsy.

Figure 15.6. Rear View of Headrest Showing Mounts.


fabricated with a continuous plate of 14-gauge carbon steel and is covered with the same materials as the sub-occipital pads. The device is shown in Figure 15.5.

The headrest is attached to the mounting system via a 12-inch WBI to BOCK vertical adjusting bar, an oc-cipital mounting bar, and a sub-occipital mounting fork (Figure 15.6). Each was constructed from seam-less carbon steel tubing. The vertical adjusting bar enables the Whitmyer system to be attached to an ex-isting BOCK square mount on the back of the pa-tient’s chair. The sub-occipital mounting fork con-nects both the left and right sub-occipital pads to the vertical adjusting bar. At the end of each rod is a 7/8-inch ball-rod, which attaches to the sub-occipital pad

by means of switch mount clamps, internally located in each pad. The occipital mount connects the occipi-tal pad to the sub-occipital fork with another 7/8-inch ball-rod.

A detachable forehead strap was attached to a pulley system and mounted to the headrest for prevention of vertical movement (Figure 15.7). The forehead strap is attached when the client is tired. The strap attaches to the occipital mount via a switch-mounting clamp.

The total cost of the headrest was $650. This includes $540 for parts and $110 for fabrication of the plaster molds.

CRITICAL! Ear clearancefrom cord of approximately 3/4"

Tension Adjuster

Position ABOVEuser's eyebrow

Side View of Soft-1 Headrest

Figure 15.7. Forehead Strap for Headrest.

197

CHAPTER 16 UNIVERSITY OF TENNESSEE AT

CHATTANOOGA College of Engineering and Computer Science

Chattanooga, TN 37403


Edward H. McMahon (423) 755-4771 [email protected]


BICYCLE FOR A SMALL CHILD Designers: B. Parr, B. Plemmons, B. Vandagrifff

Client Coordinator: Jamie Castle Tennessee Early Intervention System Supervising Professor: Dr. Edward H. McMahon

College of Engineering and Computer Science University of Tennessee at Chattanooga


INTRODUCTION A bicycle was designed for an energetic, healthy, in-telligent three-year-old boy with achondroplasia (dwarfism). The pedal-powered device enables the client, 28 inches tall, to propel himself in the same way as other children his age. The criteria were ease of mounting and dismounting, pedal power, safety, and durability. The physical restrictions were pri-marily influenced by his eight-inch inseam and an approximate 5 1/2" range of motion for his leg movement. The initial design was based on a go-cart frame; however, the family preferred a bicycle type device.

The design is based on a single downtube with no cross bar. A local world-class manufacturer of racing bicycles assisted in construction.

SUMMARY OF IMPACT The bicycle met the child’s needs. It was delivered with training wheels and sufficient adjustment in the seat to accommodate future growth. The bicycle was delivered with 12" wheels but was designed to also accommodate 16" wheels.

TECHNICAL DESCRIPTION The frame was specially designed and built to ac-commodate the dimensions of the client. It was im-portant that the client be able to get on and off the bi-cycle independently. Three frame designs were con-sidered and the one shown below was selected. The frame was made by a local bicycle manufacturer out of titanium tubing.

The components for the bicycle were standard, modi-fied as necessary. The front and rear sprockets each have 18 teeth. Either or both may be changed when the child is older. The crank was modified to a 3.5"

radius. The spindles, bearing cups, bearings, pedals, and wheels were standard, as well as the chain, fork and stem. A standard seat post was welded to the frame and a standard seat was attached.

The forks used were made for 16" wheels, although the wheels delivered with the bicycle were 12". Stan-dard training wheels were attached.

The cost of the parts for the bicycle was $275. The frame was manufactured and donated by the bicycle manufacturer.

Figure 16.1. Bicycle for a Small Child.

Chapter 16: University of Tennessee at Chattanooga 199

12.00

1.75

R7.75

R9.00

Figure 16.2. Diagram of Bicycle.


COMPUTER WORKSTATION Designers: A. Elkhadrawy, A Guider, R. Ng, T. VanHoesen

Client Coordinator: Molly Littleton Supervising Professor: Dr. Edward H. McMahon



INTRODUCTION A computer workstation was designed for use by a child. The client required a computer workstation with a monitor adjustment from 24” to 40". In addi-tion, the computer workstation should be mobile and fit through a standard doorway (36" wide). The key-board height was adjustable, and the keyboard could be moved in and out at an adjustable angle. A com-mercially available keyboard was attached to the monitor support. A motorized screw was used to ad-just monitor height. A stationary CPU support was built to accommodate a desktop or tower unit.

SUMMARY OF IMPACT The workstation met the client’s needs. The child is able to use the workstation while sitting or standing.

TECHNICAL DESCRIPTION There are two primary components, the frame and the adjustable monitor/keyboard support.

The frame was built primarily from 2" x 2" steel tub-ing. The overall dimension of the frame were 36L x 30"W x 12"H (excluding the casters). A triangular support was used on the right side of the frame. A square support was used on the left side of the frame to accommodate the CPU table.

The square tubing was miter cut and welded to form the frame. The CPU table was made from 3/4" White Melamine coated board. The frame base was com-pleted with 4" diameter nylon locking swivel casters. A strap was added to the CPU table to secure the CPU in transport.

The basis for the motorized lift was an electric screw-driven lift with a stroke of 12.5" and a lift speed of 10" per minute. The operating range was from 25.5” to 38". The motor was mounted to the frame. The shaft

end was mounted to the monitor shelf using a steel plate welded to a center sleeve. To stabilize the moni-tor tray, two steel pipes were welded to the frame. Two brass rods were attached to the monitor tray and fitted into the steel pipe. The monitor shelf was made of 3/4" White Melamine coated board. A strap was added to secure the monitor during transport.

The keyboard support and tray were purchased. The support was mounted under the monitor shelf. The keyboard can be adjusted up and down, in and out, and at an angle. The keyboard has a padded wrist rest.

Figure 16.3. Computer Workstation.


A power cord and three-way (up, off, down) momen-tary contact switch completed the construction.

The cost of the device was $600.

14"

36"

12"

2" X 2" Square Tubing

Linear Actuator

Steel Pipe 0.814" ID

Brass 0.8" OD

Melamine finishedparticle board

Melamine finishedparticle board

Figure 16.4. Diagram of Computer Workstation.


SUPPORTIVE DINING CHAIR Designers: S. Grody, M. Hobbs, J. VanSteenburg

Client Coordinator: Rick Rader Supervising Professor: Dr. Edward H. McMahon



INTRODUCTION A chair was designed to enable a client with cerebral palsy to sit at a dining table. In a standard dining room chair, the client had to sit on the edge of the seat so that his feet could reach the floor while he sup-ported himself on the table. This position made eat-ing difficult. Critical needs included support for the feet above the floor, an ability to get into the chair, and a sense of stability while in the chair. A chair was designed using PVC pipe. A sliding footrest and lightweight shoulder straps were added for support. The sliding footrest retracts when the client enters the chair and is slid forward to provide support for his feet while he is at the table. The client can enter the chair by himself. The shoulder straps enable him to remain upright.

SUMMARY OF IMPACT The chair allows the client to sit at the table and eat in an upright position. The removable cushions are eas-ily cleaned.

TECHNICAL DESCRIPTION A primary concern was the design of the moveable footrest. Mechanisms similar to those used on wheel-chairs were considered but would have made footrest adjustments difficult while the client's feet were un-der the table. The design selected was a chair made from PVC piping (Figures 16.5 and 16.6).

The back of the chair was designed for maximum support and rigidity. A second back support pro-vides handles for moving the chair. The sliding foot support was made by enlarging the inside diameter of the fittings so they would easily slide over the PVC pipe. The footrest is made from PVC cutting board material. The back and seat cushions were made of foam rubber covered with vinyl. The back cushion has snaps at the top and bottom and the seat cushion

has snaps on four sides for attachment to the PVC pipe.

The chair sits on 2 3/4" locking/swivel casters. The casters are attached to the PVC pipe frame by plugs in the bottom of the PVC frame, drilled for the caster shaft.

The PVC pipe and all joints were put together with PVC glue.

The cost of the device, including the cushions, was $300.

Figure 16.5. Photograph of the Chair.


6 1/4"

1' - 0"1' - 1"5"

2" - 6"

10 1/2"

1' - 2"

6 1/2"

1' - 11 1/2"

7"

3"' - 2"

8 1/8"

SEAT CUSHION

REAR CUSHION

Figure 16.6. Diagram of Dining Chair.


LAPTOP SUPPORT Designers: B. Bacon, M. Moss, B. Smith




INTRODUCTION The laptop computer mount was designed for a 26- year-old graduate with amyotrophic lateral sclerosis. The client uses a laptop computer and a voice synthe-sizer to communicate. This requires a tray to mount both the computer and an infrared device to access the voice program. It was necessary that the support be mounted on the left side of his wheelchair, be able to swing out of his way with ease, be easily removable and lightweight, and securely hold the computer and sensor.

SUMMARY OF IMPACT The mount met design criteria. The laptop mounts on a vertical bar on the side of the wheelchair and is easy to move out of the way to facilitate transfer to and from the wheelchair. The laptop can be easily re-moved from the mount by unlocking a gate latch and removing the tray and laptop as one unit.

TECHNICAL DESCRIPTION The vertical mount was made from 18" long 9/16" di-ameter steel tubing. A hole in the tubing and a 1/4" locking pin prevented rotation. The top of the rod was threaded.

A 2.5"x 2.5" x 8" block of aluminum was drilled and tapped for placement on top of the vertical support. The threaded connection was secured with a 10-32 set screw. On the face of the aluminum block, at right angles to the vertical support, two .5" holes were drilled. The two supporting rods for the laptop tray were made of aluminum 12" long and .5" in diameter. One end of each of the rods was threaded and screwed into the corresponding hole in the aluminum block.

The tray was made of .5" thick gray PVC board. It was 12.5" long and 10.5" wide. Four clear plastic .5"

diameter tube straps were secured to the bottom of the tray using screws.

A gate latch secures the tray to the mount. The receiv-ing portion of the latch was mounted to the alumi-num block with screws. The post portion of the latch was attached to the bottom of the tray using two screws.

The computer was secured to the tray using four 4" x 2" pieces of industrial strength Velcro. For additional safety, three small clamps were attached to the tray to secure the computer.

Figure 16.7. Laptop Support.


The cost of this device was $80.

6"8"

2 1/2" 12"

17"

1/2 inch diameter Al Rod(rod threaded into blocks)

Al block drilledand tapped

Figure 16.8. Diagram of Laptop Support.


PRINTER SUPPORT Designers: Scott Brown, Bryan Crawford




INTRODUCTION A printer mount for a wheelchair was designed for use by a client with quadriplegia. The client uses a Delta Talker, and augmentative communication de-vice, and desired a printout of the text he developed using the device.

SUMMARY OF IMPACT A mount used previously interfered with the client’s line of sight and did not provide the necessary clear-ance for the infrared signal to the Delta Talker. The new printer mount secures the printer in an optimal

position. It is simple to mount the printer. The mount allows easy access to change paper.

Figure 16.9. Printer Support.


TECHNICAL DESCRIPTION The basis for the design was an aluminum double gooseneck for a mountain bike. The tubular part of the gooseneck (which normally goes into the bike frame) was milled on an angle to produce a flat sur-face. Two holes were drilled in this portion for at-tachment of the printer mounting plate.

The printer mounting plate was constructed from a single piece of 16-gauge aluminum. Tabs in the plate support the printer and the printer paper roll. After the plate was cut the tabs were folded for the printer and paper. A 1/4” diameter rod was threaded on one

end and attached to the printer mount for the paper. It was held in place by a wing nut. The printer mounting plate was attached to the modified goose-neck by two bolts. To attach the printer mount to the rod that supports the Delta Talker, the four bolts were removed from the gooseneck and the mount was at-tached to the rod (where the bicycle handles would normally be attached). The printer is attached to the mount using Velcro.

The total cost for the device was $40.

Figure 16.10. Another View of the Printer Support.

209

CHAPTER 17 UNIVERSITY OF TOLEDO

College of Engineering Department of Mechanical, Industrial and

Manufacturing Engineering Toledo, Ohio, 43606-3390


Nagi Naganathan, (419) 530-8210 [email protected]

Mohamed Samir Hefzy, Ph.D., PE. (419) 530-8234 [email protected]


ADAPTATION OF A RIDING LAWNMOWER FOR A PERSON WITH PARAPLEGIA

Designers: Kevin Groff, Nick Homan, Ahmad Mamat, Shinta Maxfari, Rudy Santoso Mechanical Engineering Students

Client Coordinator: Dr. Gregory Nemunaitis Rehabilitative Medicine, Medical College of Ohio and St. Vincent Mercy Medical Center

Supervising Professor: Dr. Mohamed Samir Hefzy Biomechanics Laboratory

Department of Mechanical, Industrial & Manufacturing Engineering The University of Toledo

Toledo, Ohio, 4360

INTRODUCTION The purpose of this project was to adapt a riding lawnmower (Simplicity 6200) so that a person with paraplegia could operate it, while still maintaining the standard operation for use by able-bodied family members. The clutch and seat were modified. A clutch lever arm assembly was designed and built to allow the client to depress the foot pedal using hand and arm movements instead of leg and foot move-ments. The seat was replaced to provide maximum support for the client’s upper body and allow for easy transfer from a wheelchair.

SUMMARY OF IMPACT A clutch lever arm assembly was designed, built and installed in a lawnmower to allow the client to oper-ate it without use of his legs. This assistive device will allow this person to gain more independence in his daily living activities, thereby contributing to the improved quality of life for him and his family.

TECHNICAL DESCRIPTION Operation of the lawnmower requires depressing a foot pedal (clutch pedal) to engage the brakes and si-multaneously disengage the drive shaft. While the foot pedal is depressed, the gears can be changed. Re-leasing the foot pedal disengages the brakes and en-gages the drive shaft. Therefore, modifications of the clutch and seat were necessary to adapt this lawn-mower for use by the person with quadriplegia.

CLUTCH LEVER ARM ASSEMBLY, DESIGN, AND INSTALLATION The existing clutch is foot controlled, thereby elimi-nating the opportunity for a person with paraplegia to operate the lawnmower. A clutch lever arm assem-bly was designed, manufactured, and installed to al-low the drive system of the lawnmower to be engaged and disengaged using the operator's hands and arms.

The drive system of the lawnmower is a variable speed pulley system. The distance the foot clutch will travel backward, as the drive system of the lawn-mower engages, is contingent on the gear of the drive system. For example, if the drive system is in first gear, the return travel of the clutch will be approxi-mately one inch. Accordingly, if the drive system is in second gear, the return travel of the clutch will be ap-proximately two inches. In the highest gear of the lawnmower, the return travel will be equal to the total return travel of eight inches. The design of the clutch assembly must allow for the varied return travel dis-tance of the clutch.

Design criteria included that:

• The modified clutch assembly provide a stop-ping time the same or better than that for the ex-isting foot-controlled clutch;

• The drive system remain disengaged without assistance from the operator once the drive sys-tem is disengaged;

• Potential leg and foot obstructions for the opera-tor be eliminated;

Chapter 17: University of Toledo 211

• the clutch assembly be easily removable, so fam-ily members can operate the lawnmower with the foot-controlled clutch;

• it be cost effective;

• The structural integrity of the original mower be maintained; and

• The new clutch assembly be safe.

Several possible solutions were considered, including a hydraulic cylinder assembly, a screw drive motor assembly, a cable and pulley system, and a clutch lever arm assembly with a bottom pivot or center pivot. The clutch lever arm with a bottom pivot was selected. A lever arm, pivoted at the bottom with a rod hinged through a hole approximately six inches above the bottom of the lever arm, was connected to the clutch pedal. The lever arm assembly, located on the clutch side of the lawnmower, was mounted on the footrest. Pushing the lever arm forward forced the hinged rod forward and in turn disengaged the clutch and drive system of the lawnmower.

The design and manufacture of the clutch lever arm assembly included three components: clutch lever arm, push pull rod, and clutch pedal. Each of these included design of new parts, modifications of exist-ing parts, and calculations for critical design points.

CLUTCH LEVER ARM The lever arm, purchased from McBride Equipment, Inc., is the same as that used to raise and lower the mowing deck. It has a spring-loaded locking system, which allows the operator to disengage the clutch and use both hands to shift gears. The lever arm comes with a 0.125-inch thick steel base plate to en-sure secure mounting on the mower.

Three lever arm modifications were made. The first consisted of decreasing the width of the steel base 2.5 inches because the original width of the base was too wide and did not leave room for the operator to place his foot to the inside of the lever arm. This modifica-tion necessitated the removal of a large angular steel piece from the end of the rod through the lever arm base.

The second lever arm modification was a result of the first. Since the lever arm base had to be decreased,

only two bolts could be used to support and to con-nect the base of the lever arm to the footrest of the lawnmower. The existing holes in the lawn mower footrest are 0.25 inches in diameter. Design calcula-tions indicated that two 0.25 inch standard grade UNC-20 bolts would provide the required stability and strength needed for mounting. This required drilling an additional 0.25 inch diameter hole into the base of the lever arm. The location of the hole was de-termined through visual inspection and marked on site through the use of a scribe.

The third modification of the lever arm required relo-cation of the push pull rod hole. The original 0.625-inch diameter hole, six inches above the base of the lever travel distance of eight inches, was not sufficient for engagement and disengagement of the lever arm. A new hole was mounted 14 inches up on the lever arm. The lever arm is bottom pivoted, so the higher up

Figure 17.1.Modified Clutch Lever Arm.

Figure 17.2. Push Pull Rod Assembly.


the hole is along its radius, the more travel distance the hole provides. To provide additional adjustment in travel distance, a 6” x 2” x 0.25” (length x width x thickness) bracket with three 0.625-inch holes spaced 1.5 inches apart were manufactured. The new bracket, shown in Figure 17.1, was welded to the lever arm with the bottom hole 14 inches above the base of the arm. Figure 17.1 shows the modified lever arm.

PUSH PULL ROD The push pull rod of the Clutch Lever Arm Assembly transmits the motion of the lever arm to the clutch pedal. It consists of a 0.5 inch diameter steel rod 20 inches in length with a two-inch bend on one end, as shown in Figure 17.2. The straight end of the push pull rod is threaded up 8.375 inches from its end for 0.5inch UNC-13 nuts. On the two- inch bend end of the push pull rod, there is a 0.125 inch through hole for a standard cotter pin.

The bend end of the push pull rod goes through one of the three holes of the lever arm bracket, with a 0.5inch washer between the lever arm and cotter pin. There is also a 0.5 inch nylon bushing that attaches to the bend end of the push pull rod after it has been put through the lever arm bracket hole and before the cot-

ter pin and washer are installed. This nylon bushing decreases the slack between the 0.5-inch-diameter rod and the 0.625-inch diameter bracket holes.

The cotter pin and washer secure the push pull rod to the lever arm. On the threaded end of the push pull rod, there are two 0.5inch UNC-13 nuts snugly tight-ened against each other. On the rod end side of the nuts, there is another 0.5 inch washer that goes be-tween the nuts and the aluminum angle on the clutch pedal, through which the push pull rod is inserted. On the other side of the aluminum angle are two more 0.5 inch UNC-13 nuts tightened to snug tight condi-tion against each other for safety.

CLUTCH PEDAL The existing clutch pedal was modified so that it would not have to be removed with either clutch as-sembly in place. Figures 17.3 and 17.4 show the clutch pedal before and after modification, respec-tively. An aluminum angle was welded to the lip on the backside of the pedal. A 0.5625-inch diameter hole was located on the top side of the 3.75” x 3.5” x 0.25” angle in which the push rod would be inserted.

Figure 17.3. Clutch Pedal Before Modification.

Figure 17.4. Clutch Pedal After Modification.

Figure 17.5. Clutch Bar Before Phase 1 Installa-tion.

Figure 17.6. Modified Clutch Pedal Mounted On Clutch Bar After Phase 1 Installation.


The corners of the top part of the angle were rounded to remove the sharp edges and to provide a finished look.

FINAL ASSEMBLY Figure 17.5 shows the initial lawnmower clutch. The modified clutch pedal was reinstalled onto the exist-ing clutch bar as shown in Figure 17.6. The lever arm was then installed. Two 0.25-inch diameter UNC-20 bolts with corresponding nuts and washers were used to attach the base of the lever arm to the footrest of the lawnmower as shown in Figure 17.7. The bolts were tightened to snug tight condition using a hand ratchet wrench. Loctite™ bolt sealant was applied for final assembly. The sealant keeps the bolts from com-ing lose due to vibration during operation.

Finally, the push pull rod was installed. The push pull rod was screwed on to the rod using two 0.5-inch UNC-13 nuts approximately six inches up the thread from the end. A 0.5-inch washer was added behind the two UNC-13 nuts. Next, the threaded end of the push pull rod was inserted through the 0.5625-inch

diameter hole in the aluminum angle on the clutch pedal. The 2-inch bend end of the push pull rod was then inserted into the middle hole of the bracket welded onto the lever arm. A 0.5-inch nylon bushing was placed onto the 2-inch bend end of the push hole.

Next, another 0.5-inch washer was placed onto the 2-inch bend end of the rod, past a 0.125inch cotter pull rod, and into the middle bracket pin hole. A cotter pin was then inserted into the hole. Two other 0.5inch UNC-13 nuts were screwed onto the threaded end of the rod, approximately two inches away from the backside of the aluminum angle.

The two 0.5-inch UNC-13 nuts on the front side of the aluminum angle were adjusted to meet the comfort and accessibility needs of the operator. Finally, all four of the 0.5-inch UNC-13 nuts were tightened to snug tight condition against each other, ensuring se-curity and safety. Figure 17.8 shows a picture of the fully assembled clutch lever arm assembly.

Figure 17.7. Clutch Lever Arm Attached To The Footrest.

Figure 17.8. Clutch Lever Arm Assembly Fully In-stalled

Figure 17.9. Existing Lawn Mower Seat.

Figure 17.10. New Lawn Mower Seat.


SEAT MODIFICATIONS The existing seat of the riding lawn mower did not have a seatbelt and provided no support for the upper body. Without support and a seatbelt, the user could possibly be thrown from the lawnmower. A new seat and a seatbelt were added. The new seat met the fol-lowing criteria:

• Universal mounting to allow for easy installa-tion and minor modifications to existing equip-ment;

• Fold-up arms that allow for easy entry and exit;

• High backrest and armrests to provide support and security; and

• Comfort for other operators.

A seat from Northern Hydraulics was acquired and modified to attach a seatbelt. The backrest on the new seat is 16.5 inches, which provided an additional 3.5 inches of support. Two foam-cushioned armrests provide additional side support. During transfer, the armrests can be folded up to allow the user to slide onto the seat.

The seat was constructed of a steel frame, used for seatbelt attachment. Figures 17.9 and 17.10 show pic-tures of the existing and new seats, respectively.

The new seat had to be slightly modified for secure at-tachment to the lawnmower. The new seat had four, 0.25-inch diameter pre-drilled holes. However, the rear two holes did not line up with the existing mounting bracket. To remedy this, two additional 0.25inch-diameter holes were drilled through the steel frame of the seat. The seat was then attached to the existing mounting bracket using four 0.25-inch di-ameter bolts. To attach the seatbelt to the new seat, two, 3/8 inch-diameter holes were drilled through the steel frame of the backrest. The seatbelt was attached to the new seat using two, 3/8 inch-diameter bolts.

OPERATION AND EVALUATION OF THE ADAPTED LAWNMOWER The operation of the clutch lever arm assembly begins when, using his or her right arm, the operator firmly pushes forward on the lever arm of the assembly to bring the mower to a full stop and to lock the clutch into disengagement. Force is transmitted from the

arm of the operator to the assembly lever arm. Federal regulations require that the clutch assembly provide a mechanical advantage for the operator. The maxi-mum force needed to disengage the drive system (or conversely, engage the brakes) should not be greater than 50 pounds. It was found that the force that needs to be supplied by the arm of the operator to the assembly lever arm is approximately thirty pounds, which is less than the maximum force allowed by the federal regulations. From the assembly lever arm, the force is transmitted through the bracket to the push pull rod. The force is then transmitted along the length of the push pull rod and applied to the clutch pedal as a result of the two nuts pushing against the front side of the aluminum angle.

To release the clutch pedal, the operator pushes in the button at the top of the lever arm, releasing the spring-loaded locking system and slowly allows the clutch pedal to travel back and engage the drive system. The lever arm is forced back by the spring-loaded clutch pedal. The force from the pedal is transmitted through the angle on the pedal pushing against the two front side nuts.

Figure 17.11. Foot Clearance With Clutch Lever Arm.

Figure 17.12. Hand Clearance Between Lever Arms Assembly Attached.


Each component was evaluated while simulating the operation of the lawnmower by a person with para-plegia. This test was recorded on a standard VHS video and included the following tasks:

• Folding the arms;

• Securing the operator with the seatbelt;

• Checking clearance between the operator’s foot and the clutch lever arm assembly;

• Checking clearance between the mower deck lever arm and clutch lever arm assembly;

• Locking the clutch lever arm assembly to disen-gage the drive shaft;

• Changing gears;

• Releasing the clutch lever arm assembly to en-gage the drive shaft; and

• Simulating normal stopping using the clutch lever arm assembly and recording stopping times.

The test adequately displayed the effectiveness of the clutch level arm assembly and the new seat. The op-erator is provided ample body support, and the seat-belt effectively secures the operator to the seat. With

the clutch lever arm assembly attached, the operator still has sufficient clearance to place his/her foot on the footrest, as shown in Figure 17.11. Also, the clutch lever arm assembly does not interfere with the normal operation of the mower deck lever arm. Fig-ure 17.12 shows the distance between the clutch lever arm assembly and the mower deck lever arm. The clutch lever arm assembly can be locked in the for-ward position, disengaging the drive shaft, as shown in Figure 17.8. This allows the operator to use both hands to change gears. Finally, using the clutch lever arm assembly does not negatively affect the stopping time. Stopping times using the clutch lever arm as-sembly were compared to stopping times using the existing foot pedal and foot-activated stopping. The stopping times for the two methods were almost equivalent on average to 1 sec.

The total costs of the material were $240.00. The price of the seat was $97.52, and the lever arm was pur-chased for $95.00. These costs do not include ma-chining costs of cutting, drilling and welding.


DRINKING SYSTEM FOR PERSONS WITH QUADRIPLEGIA

Designers: Kathleen Church, Scott Campbell, Jason Wendle, Hussain Madoh, Mechanical Engineering Students




Toledo, Ohio, 43606

INTRODUCTION The purpose of this project was to develop a system that allows patients with quadriplegia to drink water independently while in bed when no assistance is available. The prototype can be mounted to any hos-pital bed. The unit includes an adjustable, flexible ex-tension arm that ends with a mouthpiece. The arm is welded to a sleeve into which a main support post slides. Such a post is typically located near the head of most hospital beds. Water bottles and a waterline are also supported by this post. The prototype mounted on a hospital bedpost is shown with the arm extended in Figure 17.13 and with the arm par-tially retracted in Figure 17.14

SUMMARY OF IMPACT Patients with quadriplegia have little or no control of the body below the neck. This makes it impossible for them to get a drink of water independently. Dehydra-tion becomes a problem when such individuals are without assistance.

Users are able to use this system and attain water by adjusting the mouthpiece location using only neck movement, provided the mouthpiece is placed by the user's head. This design is also effective for patients with limited use of one arm, as they do not need the mouthpiece by their heads all the times.

TECHNICAL DESCRIPTION Designs with and without motorized arms were con-sidered. The motorized option was dismissed be-cause of safety aspects. If a system failure were to oc-cur, the user would be unable to move out of the path

Figure 17.13. Drinking Unit Mounted on a Hospital Bedpost with Arm Extended.

Figure 17.14. Drinking Unit Mounted on a Hospital Bedpost Post with Arm Partially Retracted.


of the arm and may suffer further injury. The proto-type consists of three main parts: the main support post, the water bottle, and the extension arm.

The main support post is typically made of 3/4-inch stainless steel tubing and slides into a sleeve located near the head of most hospital beds. The water bottle is supported from the top of the post with a bottle-holding gripper. The post also supports the excess water line, necessary for height adjustment, with a support hook, as shown in Figures 17.13 and 17.14. Additionally, the main post supports the extension arm by a 1-inch steel sleeve with two inline holes. Hand retractable plungers that fit these holes are used to adjust the position of the sleeve along the post, setting the height of the arm at the desired loca-tion.

The water bottle contains a machined hard plastic disc that seals its lower end. A quick disconnect valve is threaded into this disc, allowing the bottle to be easily removed for filling. Soft ¼-inch plastic tub-ing is used as water line and is attached to the lower end of the disconnect. This water line is connected to a check valve that prevents leakage. The check valve is mounted at the end of the extension arm. The mouthpiece is connected to the check valve and con-sists of a short 1/4-inch tubing. All non-plastic com-ponents that come in contact with water are made of corrosion resistant material.

The extension arm is welded to the steel sleeve of the main support post. The arm consists of four sections. The first section is a stay-put flexible PVC coolant hose (hard plastic tubing), 15 inches in length. The check valve is attached to one end of this tubing, while the other end is threaded into a 14-inch stainless steel tube (OD = 0.75 inch, ID = 0.68 inch)

that represents the second section of the arm. The flexible hard plastic tubing forming the first section of the extension arm allows adjustment of the location of the mouthpiece connected to the check valve. The third section of the extension arm is made of an iden-tical tube (14 inches in length) that is hinged to the second section.

The fourth and last section of the extension arm is the arm support truss and consists of two members, as shown in Figures 17.13 and 17.14. The first member is a 15-inch stainless steel tube hinged at one end to the second section of the arm and welded at the op-posite end to the post’s sleeve.

The second member of the arm support truss is welded, at 30 degrees, to the first member. This mem-ber is also welded at its opposite end to the post’s sleeve. Shoulder bolts, washers, lock nuts, and tubing caps were employed at all hinges. Self-adhesive Vel-cro was used to hold the water line to the extension arm.

Assistance is required to adjust the position of the ex-tension arm on the hospital bedpost and for the re-moval, refilling, and reattachment of the bottle. Assis-tance is also required to position the mouthpiece for patients with no arm movement. A sterilization solu-tion should be processed through the system at least once a week to ensure a clean water flow from the mouthpiece. This piece should be thoroughly and frequently washed.

On a mass production scale, the plastic disc that seals the bottle would be more efficiently produced by a casting operation instead of machining.


ASSISTIVE DEVICE TO START A PULL-START LAWNMOWER

Designers: Chris Nikazy, Ryan Short, Yousef Dewaila, Aaron Lemieux Mechanical Engineering Students




Toledo, Ohio, 43606

INTRODUCTION The purpose of this project was to develop an assis-tive device that allows a person with a physical dis-ability to independently start his pull-start lawn mower. This person has weakness in his grip strength and in his arms and shoulders. The device includes a pulley that redirects a downward force as-sisted by gravity to an upward pulling force. The pul-ley is attached to a small metal frame housing wheels that roll on top of one of the beams inside the client's barn as shown in Figure 17.15. Starting the lawn mower requires him to pull down on a handle bar at-tached to a rope that wraps around the pulley and at-taches to the pull start handle of the lawn mower.

SUMMARY OF IMPACT A unit was designed and built to allow a farmer with a physical disability to independently start his pull start lawn mower. This individual cannot control the strength of his grip and cannot pull up on a cord with adequate speed using his arms and/or shoulders. The unit was safely tested and operated by the client to his satisfaction.

TECHNICAL DESCRIPTION This assistive device is used to redirect the typically strenuous upward pulling force to a simple down-ward force that is assisted by gravity. The initial de-sign consisted of a large frame that would hold a pul-ley approximately eight feet above the top of the lawn mower. This frame was also to restrict the body of the lawn mower to keep it from lifting off the ground when the cord was pulled upward. However, it was

decided to use the client's existing barn as the frame, which reduced costs.

Figure 17.16 shows a close-up of the prototype. It in-cludes a pulley attached to a small metal frame that houses wheels that roll on top of a single beam in the ceiling of the client's barn. The frame is made of 0.25 inch steel plates. It consists of two vertical plates, 2 inches apart, welded to a horizontal rectangular plate (2.5 inches x 7.5 inches). The two vertical plates were

Figure 17.15. Assistive Lawn Mower Starter.


not rectangular in shape, each plate having a total height of 14.25 inches and a total width of 7.5 inches.

A sheave (pulley for small diameter wires and/or fi-brous ropes) rated at 1400 lbs. was used. The pulley had a bronze bushing and an outside diameter of five inches. The pulley was secured between the vertical plates using two pulley spacers, each being an ultra-high molecular weight polyethylene (UHMWP) rod, 1.25 inches in diameter and 0.625inches in length. Each pulley spacer was drilled through to allow the insertion of a 0.75inch-diameter drill rod that was two inches in length (which was equal to the separa-tion distance between the two vertical plates). Each end of the drill rod was drilled creating 3/8inch-diameter holes. The two pulley spacers and the sandwiched sheave were mounted on the drill rod, which was attached to the two vertical plates of the unit frame using 3/8-inch shoulder screws.

Four solid rubber wheels with hard tread and self-lubrication were used to allow the steel frame to roll on top of a single ceiling beam in the barn. Each rub-ber wheel was two inches in diameter and 15/16 inch in width. Each rubber wheel was secured between the two vertical plates of the steel frame using two spacers of UHMWP rod, 0.625 inch in diameter and 0.5 inch in length. Each rubber wheel spacer was drilled through to allow the insertion of 0.25 inch-diameter socket-head shoulder screws. Each of the four sets of three rubber wheel spacers was thus mounted on a 0.25-inch diameter screw that attached the unit to the vertical plates of the frame. The solid rubber wheels, the sheave, and the UHMWP were or-dered from McMaster-Carr Supply Company.

A one-inch diameter, 10-inch long aluminum rod was used as a handle; this allowed two hands to fit on the rod as shown in Figure 17.15. A 0.312 inch through hole was drilled in the middle of the handle to allow

for rope attachment. A 0.25 inch rope was used. The rope was attached to the handle, passed around the

pulley, and then connected to the lawnmower's pull-ing cord using a hook.

The prototype was assembled and tested successfully at the client’s barn under the supervision of his phy-sician. The total material cost was $80.00.

Figure 17.16. Pulley and Rollers.


ASSISTIVE DEVICE TO OPEN AND CLOSE LARGE JARS

Designers: Aaron Lemieux, Andy Laker, Mohammad Al-Nasser, Yaser Jamal, Mechanical Engineering Students

Client Coordinator: Dr. Greg Nemunaitis Rehabilitative Medicine, Medical College of Ohio and St. Vincent Mercy Medical Center



Toledo, Ohio, 43606

INTRODUCTION An assistive device was developed to allow a person with a physical disability independently to open and close jars of various sizes. The prototype consists of a strap wrench with a handle machined to allow it to slide into a metal block welded to a metal base, as shown in Figure 17.17. The base is bolted to a table-top for support. During operation, the handle slides into the block and opens jars, as shown in Figure 17.18. When the handle is turned around and in-serted in the block in the opposite direction, it closes jars. Using the strap as the clamping mechanism al-lows the prototype to be used on jars of different sizes, regardless of height or diameter.

SUMMARY OF IMPACT The client, a farmer, had lost sensation in his fingers due to a spinal cord injury. This device will assist him in canning produce grown in his garden or pro-vided to him by neighbors, as is the custom where he resides. The device is universal in that any person with a weakened or atrophied upper body may find it useful.

TECHNICAL DESCRIPTION The tightening/removal torques of commonly en-countered jars were determined by consulting with Owens-Brockway research and development labora-tory in Perrysburg, Ohio. Two items were picked at random from a grocery store: a salsa jar and a pickle jar. At Owens' laboratory, the jars were tested in a torque tester consisting of a steel jaw that gripped the base of the jar. The jaw was connected to a torque gauge that read both tightening and removal torques.

Torque was applied directly to the lid, as one would when opening a jar. For both jars, the average tight-ening torque was measured as 75 in-lbs. The average

Figure 17.17. Assistive Device to Open and Close Jars.

Figure 17.18. Device in Use by Client.


removal torques was 40 in-lbs. and 49 in-lbs. for the salsa and pickle jars, respectively. These results were consistent with the commonly used design guidelines indicating that the tightening torque is related to the diameter of the lid. A 70 in-lbs. torque is required to tighten a 70-mm metal lid. Conversely, it takes only 2/3 of the tightening torque to remove the lid; that is 46.7 in-lbs. to remove a 70-mm lid.

A survey of the heights of typical grocery store jars was then conducted to determine the height of the smallest typical jars that could be encountered. This was to determine whether the device needed a vari-able height adjustment to accommodate large and small jars. Based on 24 samples, it was found that common jars have an average height of 6.2 inches (± 1.4 in.) with a minimum height of 3.9 inches and a maximum height of 10.4 inches. Using these data, it was determined that only one height was needed to clamp all the jars surveyed.

The jar-clamping device consists of a Ridgid brand strap wrench manufactured by Ridge Tool Company, Elyria, Ohio. A steel block with a 3 x 3-inch base and 4-inch height, was used to support the wrench. The handle of the wrench was machined to enable the can to slide into the steel block.

Because it was difficult to drill a hole through the steel block that allows the machined handle to slide into it, the block was divided into two equal small

blocks, each with a height of two inches. Each of these small blocks was then machined such that when attached together, a through hole was created with a cross-section matching that of the machined handle.

Once the handle was inserted between the two small blocks, they were secured together using two 0.375-inch bolts. The bottom small block was welded to a steel base plate that was bolted to a tabletop using four 0.25-inch bolts. The base plate was made from 0.25-inch steel and was square in shape (16 x 16 inches). Figure 17.17 shows a picture of the unit. Figure 17.18 shows a schematic illustrating the ma-chining details of the two small blocks.

During operation, the strap of the wrench is tightened around the jar, generating a friction force that inhibits jar movement. To open a jar, it is placed within the strap with its bottom resting on the base plate. Pull-ing the loose end of the strap causes the strap to be pulled tightly around the jar. With the jar in the strap, the user places his hand on the lid and turns it, making the strap tighten further and causing the lid to be removed.

The device is also used to close jars when the handle is removed, turned around, and inserted between the two small blocks in the opposite direction.

The total cost of the unit including machining, parts, and dissemination material, was $180.00.

Minimum thickness .940

Match uniform thickness

R1.50 (optional)

.250 3.000

16.000

.3852.125

4.000

.375 x 2 Bolts

Figure 17.19. Schematic Showing the Machining of the Fixation Blocks Allowing Insertion of the Machined Handle (Dimensions in Inches).


REACHER DEVICE Designers: Kurt Hilvers, Jody Claypool, Andy Olszewski, Ahmad Al-Abdulrazzag,

Mechanical Engineering Students Client Coordinator: Dr. Gregory Nemunaitis

Rehabilitative Medicine, Medical College of Ohio and St. Vincent Mercy Medical Center Supervising Professor: Dr. Mohamed Samir Hefzy

Biomechanics Laboratory Department of Mechanical, Industrial & Manufacturing Engineering

The University of Toledo Toledo, Ohio, 43606

INTRODUCTION A heavy-duty reaching device was designed to allow persons with paraplegia or people with limited reach-ing capabilities to grasp an object from 6-8 inches in diameter and up to 25 pounds in weight. The unit consists of a hollow aluminum shaft, a nylon cable noose, a ratcheting lock grip handle, and two lock re-leases, one at the handle and one at the noose end. The reacher extends 5.5 feet away. Figures 17.20 and 17.21 show the device being used by an individual with paraplegia in his garage.

SUMMARY OF IMPACT A device was designed and built to allow an active person with paraplegia to reach and grasp heavy and large objects independently. Previously, his means of obtaining those objects was to knock them off the shelf with a rake, which was impractical and danger-ous. The reacher prototype allows him to reach those objects in a more convenient and safe manner. Many people have difficulty reaching up to a cabinet, or picking an item up off a shelf. Currently, the avail-able selection of reachers on the market is limited to those for grasping small, light objects from a short reach. The most common design in the market sup-ports objects up to 4 pounds and widths of up to 4.5 inches. This reacher supports objects that are up to 25 pounds and has an adjustable noose capable of carrying objects 2 to 10 inches in diameter with an ex-tended reach of 5.5 feet.

TECHNICAL DESCRIPTION Several design concepts were considered including jaw, telescoping, reel, and noose designs. Criteria in-cluded that the unit be lightweight, stable, safe, and easy to use. The noose design was found to be most

Figure 17.20. Reacher in Use.

Figure 17.21. Reacher in Use.


versatile. It better accommodates the needs of a greater number of consumers due to its better grasp-ing ability.

The noose consists of a 12-foot long cable, which wraps around any object being picked up. The cable tightens around the object, locking into position once it has secured a specific tightness. The shaft of the reacher is made of aluminum 3003, providing enough stability not to bend once the object has been removed from the floor or the shelf. The shaft has an OD of 1.5 inches and a thickness of 0.065 inch. Its length was predetermined to be 5.5 feet long, to provide the great-est amount of benefit for household use. Once tight-ened, the ratcheting lock-grip handle, which remains tight. This allows the user’s hands to remain free when they are retrieving the object from the noose end. The lock-grip design incorporates two releases. The first release is by the handle, which makes releas-ing an object from a distance easier. Also, this facili-tates placing an object on a shelf and changing from one object to another. The second release is at the noose end. This release allows the users to get the ob-ject once it has been lowered in front of them. A quick grip bar clamp from the American Tool Company, shown in Figure 17.22, was modified to make the handle and trigger assembly. The clamping ends were removed. The upper surface of the grip was milled down. The clamping part was inverted on its shaft, as shown in Figure 17.23. The shaft required machining. A hole was cut for the lock-grip handle to be inserted, and holes were tapped into the shaft for screws to secure the handle. A V-shaped rubber stop assembly was also mounted to the shaft at its grasp-ing end. This portion was added to the shaft to sup-port objects while they are gripped.

The handle operates on a sliding rod mechanism. The rod, which extends a distance of 12 inches from the back of the handle, slides through the top of the handle. As the handle is compressed, two metal strips that lie flat with the handle are tilted at an an-gle. Simultaneously, the strips grab the rod and pull it. The end of the rod in front of the handle is welded to a disk that slides along the diameter of the shaft. The disk, which is located in between the handle and the noose, is attached to the cable with lynch nuts. The other end of the rod is bent upward, perpendicu-

lar to the shaft. This bent portion acts as a handle to adjust the noose when it has not been secured.

The prototype was tested and evaluated by a person with paraplegia, as shown in Figures 17.20 and 17.21, under the supervision of his physician. Oper-ating instructions were clearly explained to the client before he attempted to use the device.

The client indicated he will use the device often and that the reacher will be a tremendous aid to him. Since some parts may become worn over time, it is suggested that the cable and the bolt connecting the rubber stopper assembly to the shaft be replaced after an extended period of use. It is also noted that the reacher's shaft is made of aluminum and will be be-come slippery if exposed to oil or water. The total cost of parts was $70.34. With mass production, the reacher's price would be almost half the cost of this prototype. The rubber stopper assembly could be molded into the shaft, which could be made of thin-ner aluminum or plastic composite.

Figure 17.22. Quick Grip Bar Clamp.

.

Figure 17.23. Quick Grip Bar Clamp After Modification


WHEELCHAIR BICYCLE-TYPE ATTACHMENT Designers: Brian Kremer, Chris Sneider, Maitham Taqi, Tran Nguyen, Muhaiman Ahmad, Mohamad Al-Kazimi,


Rehabilitative Medicine, Medical College of Ohio and St. Vincent Mercy Medical Center Supervising Professor: Dr. Mohamed Samir Hefzy



INTRODUCTION A bicycle-type attachment was designed for use by a person with paraplegia in a wheelchair. The client has normal control of his arms and upper body. The objective was to allow him to use his arms to propel himself by hand pedaling the attachment unit when it is temporarily connected to his wheelchair. During operation, the front wheels of the wheelchair are off the ground, thus making the structure, composed of the wheelchair and attachment unit, function as a tri-cycle. Operating this tricycle structure allows the pa-tient to exercise different muscle groups in his arms.

SUMMARY OF IMPACT This prototype was constructed for a person with paraplegia who is very active and enjoys outdoor ac-tivities with his family. Persons with paraplegia con-fined to wheelchairs often have limited opportunities to enjoy outdoor activities. Often, these patients can-not engage in public recreational activities because of the cost and availability of appropriate sporting equipment, such as racing wheelchairs. Using an af-fordable bicycle-type attachment unit that is easily connected to a wheelchair transforms it readily to a recreational hand pedaled tricycle.

TECHNICAL DESCRIPTION A bicycle-type attachment unit was designed to sat-isfy the requirements that it have no permanent at-tachments to the wheelchair, allow the user to propel himself using hand pedals, lift the small front wheels of the wheelchair off the ground during operation, and be safe, lightweight, and user-friendly, allowing the user to attach and detach the unit independently.

Figure 17.25 shows the different parts of the attach-ment unit and its connections to the wheelchair. The attachment unit incorporates a regular 24-inch bicy-cle wheel (not labeled in Figure. 17.25), a three-speed coaster brake, a front wheel bicycle fork, a steering arm, a crank-drive assembly (not labeled in Figure 17.25, but consisting of hand pedals, crank arms and a drive sprocket), a drive chain (not shown in Figure 17.25) and a connecting frame made from one-inch nominal steel tubing.

The front wheel bicycle fork has to be custom-fit to the three-speed-coaster brake hub, which usually pro-vides a rear wheel drive in most bicycles. The crank drive assembly drives the chain, which drives the three-speed-coaster brake that provides three forward speeds and allows the user to decelerate by using a reverse rotation motion of the drive sprocket.

The steering arm was welded to a headset that rotates within the steering tube, causing the front wheel fork

Figure 17.24. Tricycle in Use by a Client with Quad-riplegia.


to rotate also within the steering tube. A bracket was attached to the headset to provide a guide for the drive chain. Hence, the chain path is from the drive sprocket to the guide bracket to the three-speed coaster hub and back around to the drive sprocket. This path was selected to allow the chain to avoid contact with the fork and the connecting frame at all times.

The design allows the attachment to be connected to the wheelchair using clamps located on the connect-ing frame and secured to the wheelchair on each side of its supporting frame, just below the patient’s knees. These clamps were coated to prevent damage and/or slippage while attached to the wheelchair. They also have a cam-locking device to prevent them from be-coming loose. Also, the design allows the front wheels of the wheelchair to be supported by the at-tachment unit using two racks located on the bottom part of the connecting frame. The two racks, made of fourteen-gauge steel, were connected with a schedule forty steel channel.

During the attachment process, the user rolls the front wheels of his wheelchair into the two racks that pro-vide a stop. He then secures the front wheels in place by inserting a set of two pins in each rack. The user then turns down two screwjacks, one attached to each

rack, to lift the racks housing the front wheels, pro-ducing a slight backward tilt of the wheelchair. These hand-operated screwjacks allow for a clearance up to two inches off the ground. The user then ex-tends the upper part of the connecting frame using two turnbuckles, thus allowing the clamps to be se-cured to the supporting frame of the wheelchair. Fi-nally, the user turns up the screwjacks, converting the attachment unit and the wheelchair into a tricycle type structure.

Figure 17.24 shows the patient sitting in his wheel-chair with the attachment unit connected. During fi-nal testing, the patient was able to steer and drive the tricycle structure comfortably. It has been recom-mended to the patient to avoid high-speed turns to prevent turning over, as he has limited control of his torso movements. The patient indicated that while connecting the attachment unit to the wheelchair, turning down the screwjacks becomes difficult as the ground resistance increases. Screwjacks can be re-placed with pneumatic jacks, but this will compro-mise the simplicity of the design. Total expenses for materials and supplies were $625.00 with the bicycle wheel assembly (wheel and coaster brake) being the most expensive item, costing $150.00.

Description of parts:

6 lower support structure to base plate 7 lower support structure to steering tube 8 upper support structure to steering tube 9 turnbuckle10 steering arm11 reinforcement of upper structure12 reinforcement for upper and lower support structures13 headset going into steering tube14 steering tube15 front wheel fork16 wheel hub (3-speed coaster brake)

16151287

11 8

10 13 14 15

89

6 12 7

Figure 17.25. Bicycle type attachment


TEMPERATURE CONTROL SHOWER UNIT Designers: Ben Schaller, Christine Vance, Terry Baylis, Jason Grup, Seung-Jae Yi,


Rehabilitative Medicine, Medical College of Ohio and St. Vincent Mercy Medical Center Supervising Professors: Dr. Mohamed Samir Hefzy and Dr. Nagi Naganathan



INTRODUCTION The purpose of this project is to design and develop a temperature controlled shower unit to be used by a person with paraplegia who has little or no motor or sensory function below his arms. The unit allows the client to interactively select and set his preferred wa-ter temperature in the shower. The design of this unit incorporates a thermal mixing valve that provides op-timum temperature control, and a proportional-integral-differential (PID) controller that ensures a constant water temperature throughout usage. The valve is operated by a motor, which permits mixing cold and hot water within its body. A thermocouple measures the temperature of the mixed water and feeds it to the controller, which provides a feedback input to the motor allowing valve rotation. An anti-scald valve was also incorporated to prevent burns caused by scalding hot water that may result from system failure.

SUMMARY OF IMPACT A loss of sensation puts individuals risk for unknow-ingly injuring themselves with scalding water. Per-sons with motor and sensory loss may need assis-tance to adjust the water to keep a constant tempera-ture while washing, and while seated at the back of a bathtub on a tub bench, using a long handled shower head. With the use of a temperature controlled shower unit mounted inside the shower’s walls, pa-tients can independently determine water tempera-ture and take a shower comfortably and safely.

TECHNICAL DESCRIPTION The proposed design incorporates a thermal mixing valve that combines the output from hot and cold wa-ter supply lines into a single outlet stream having a

specified temperature. A unit composed of a PID controller, a direct-coupled actuator, and a thermo-couple, allows temperature control via an adjustable mixing valve.

Due to the wet environment, it was necessary for the control unit to operate at 24 volts and reduced am-perage. This required using a transformer to step down the power from the standard 110-volt service to 24 volts. The system and its components are shown in Figure 17.26

The thermal mixing valve was designed to sustain up to 75 psi of water pressure and to operate between 45 and 200 degrees Fahrenheit, which accounts for all possible conditions present in a typical household water system, whether it is supplied municipally or by a well with a pump. For simplicity, the system was designed to operate with a single motor where hot and cold streams are mixed within the body of the

Figure 17.26. Temperature Control Shower Unit. The System Includes: (1) Motor; (2) Mixing Valve, (3) Thermocouple, (4) PID Controller, (5) Transformer, (6) Hot Supply Line, (7) Cold Supply Line.


thermal valve. The valve is composed of body, stem, three o-rings, and a stem-retaining nut. The stem is a 0.75inch-diameter rod with two 0.5-inch holes drilled through perpendicular to each other and offset axi-ally 1.5 inches. The effect of the offset of the holes is to allow the motor to rotate the stem within the body of the valve 90 degrees. This allows the mix of the two inlet streams to vary from 100% cold flow to 100% hot flow with adjustable mixtures of hot and cold be-tween the extremes.

The stem diameter is reduced to 0.5-inches to allow for a retaining nut to hold the stem in position inside the valve body. The stem-retaining nut is made of aluminum and has a 0.50-inch hole through the cen-ter to slide over the stem. The retaining nut is threaded on the outside edge and threads into the valve body to prevent the valve stem from moving in the axial direction. Three nitrile o-rings (operating temperature between -65 and 275 0F) were employed to seal the opening where the stem exits the body of the valve, thus requiring three o-ring grooves to be machined into the valve stem. Two o-rings were used to prevent water from leaking out along the valve stem, and one o-ring to prevent leakage between the hot and cold streams.

A Watlow Series 965 PID controller was employed to regulate the temperature. The motor was selected to allow for slow rotation, which was required to reduce temperature fluctuation about the set point. A direct-coupled actuator, manufactured by Honeywell, with a stroke range of either 45o, 60o or 90o, was used. To measure the temperature of the mixed water, a T- type thermocouple with a working range of 32oF to 662oF was selected. Flexible romex wiring and connectors were employed in the final set-up. The thermocouple measured the temperature of the mixed water, and fed it to the controller, which subsequently compared it to the set temperature, and acted accordingly. The con-troller caused the motor to turn in one direction or the other, depending on whether more hot or more cold water was required in order to match the measured temperature with the set one.

A commercially available chrome plated brass anti-scald valve was added to the system. Since this valve

is small, it can be installed at any point between the gooseneck pipe and the hand held showerhead. The valve is designed to automatically shut off the water when the temperature reaches 114 ±5oF. A red reset button on the anti-scald valve can be pushed once the showerhead is directed away from the body to flush the hot water from the pipes.

The system was tested to determine the time required to respond to a significant temperature change. Two types of tests were conducted. In both tests, the valve stem was oriented to 100% cold water flow, approxi-mately 67oF. In the first test, the PID input tempera-ture was set at 215oF. The system responded by rap-idly adding hot water. In 90 seconds, the water was shut off when it reached an average of 111.5oF for two trials, which was within the designated rating of 114oF ± 5oF. In the second test to demonstrate how the PID controller determines the rate of temperature change and prevents temperature overshooting, the PID input temperature was set at 110oF. As the meas-ured temperature approached the set temperature, the rate of temperature change decreased. In about 90 seconds, the system stabilized with an average 2.15 seconds per degree over two trials.

The temperature control shower unit can be used with a standard long handled showerhead while the patient is seated on a tub bench at the back of the tub. One limitation of this system is that the mixing valve was designed to operate as a thermal-mixing valve only; isolation or shutoff valves were not included in the design of the prototype. The system can be im-proved if isolation valves are to be used for both hot and cold supply lines to start and stop flow. Fur-thermore, some improvements could be achieved if the 60° (instead of 90o) range of rotation of the motor were selected and if the orientation of the holes in the valve stem were altered. If the valve stem holes were less than 90° apart, the mixture would change more rapidly and would speed the response time of the en-tire system.

The total cost for materials and supplies was $500. The controller and motor were the most expensive items, costing $266.00 and $96.26, respectively.

229

CHAPTER 18 UTAH STATE UNIVERSITY

College of Education Center for Persons with Disabilities

Logan, Utah


Frank Redd, Ph.D. (801) 797-1981 [email protected]

Marvin G. Fifield, Ph.D. (801) 797-1981


AUTOMATIC ROCKING BENCH SWING

Design Team: Shawn Hawk, Troy Kunzler Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professors: Dr. Beth Foley, CCC-SLP, Center for Persons with Disabilities

Ms. Amy Henningsen, OTR, Center for Persons with Disabilities Utah State University Logan, Utah 84322

INTRODUCTION This project was designed for a young woman with autism who had a history of engaging in self-injurious or aggressive behavior when she was tired, bored, or frustrated. Her parents reported one of the few things that calm her during such episodes was to rock her for long periods of time, either in a rocking chair or on an outdoor porch swing.

This led to the development of an inexpensive auto-matic bench-type swing, in which the young woman was able to rock herself independently. Making the automatic swing mechanism safe and easy to use for the consumer was an important consideration. Be-cause she could use it independently, she was able to engage in an enjoyable, self-selected leisure activity. Her use of the swing provided the additional benefit of some much-needed respite for her primary caregiv-ers.

SUMMARY OF IMPACT This automatic swing was developed to meet the needs of one consumer and her family. However, the swing is appropriate for use by children (age 3+) or adults with a range of disabling conditions, who may benefit from the sensory stimulation and relaxation the swing can provide. Safety features include an ad-justable seatbelt, a padded seat, an adjustable um-brella to limit sun exposure, a weather-safe motor en-closure, and an easily accessible switch for the care-giver.

TECHNICAL DESCRIPTION The swing structure was made of 1.5" galvanized pipe for long lasting outdoor use. The framing di-mensions were made to hold a five-foot bench with room bilaterally to eliminate the possibility of pinch-ing hazards. The base is 4' x 7' with 8"x 8" steel pads used for supporting the swing in a level manner.

16” steel drive rods were used to give the swing added support in the desired location in the front lawn of the consumer’s house. The height of the frame structure is 6' 4" to accommodate the height needed for the free-moving swing.

The swing attachment is made from a 5/8" swivel with an internal bearing allowing free movement. The 5' wooden bench seat is attached to the 1.25”metal pipe swing frame. The motor is a ½ hp 110-volt AC gear motor with 30 RPM. The motor at-taches to the swing frame directly underneath the center of the bench. The motor also attaches to a steel base stemming from the lower steel frame work and is positioned in a vertical position allowing the actuat-ing arm to have unlimited lateral motion. The motor frame and bench frame are attached by an actuating arm with swivel couplers on both ends. The motor and actuating arm are encased in a protective cover to ensure safe operation.

Chapter 18: Utah State University 231

Figure 18.1. Automatic Rocking Bench Swing.


TRAILER-MOUNTED LIFT SYSTEM FOR HORSEBACK RIDING

Design Team: Justin Smith, Jeramy Jenkins Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professors: Dr. Beth Foley, CCC-SLP, Center for Persons with Disabilities

Utah State University Logan, Utah 84322

INTRODUCTION Lifting a person from a wheelchair to a horse is no easy task and the risk of injury to caregivers and con-sumers is considerable. The purpose of this project was to design an affordable lift system that would make the transfer from wheelchair to saddle easier and safer, thus making horseback riding a more ac-cessible recreational option for persons with disabili-ties.

SUMMARY OF IMPACT There are many equestrian organizations for people with disabilities in the United States. Few use lifts. A local organization that provides recreational activi-ties to its consumers with disabilities needed a lift system that was mobile and inexpensive. After sev-eral meetings with the recreational department of this organization, design criteria established were that the lift system:

• Provide a safe and easy means of lifting a person from a wheelchair on a trailer bed to above the horse’s back;

• Be adjustable and have lifting range of up to 5 feet;

• Easily pivot from the wheelchair position to the horse mounting position; and

• Be simple and cost-effective.

TECHNICAL DESCRIPTION This project incorporated three major components, in-cluding a trailer, a wheelchair ramp, and the lift sys-

tem. The trailer was 8' x 10' and had a height of 20" on its deck. Four adjustable stands were added at each corner to ensure stability and to provide for a flat surface when on uneven terrain. A wheelchair ramp was added, providing easy access to the trailer bed, easy removal, and storage on the trailer when trans-porting to a different site. The trailer and ramp were available on the market at reasonable prices.

The lift system was built to provide the recreational team a transfer method with substantial range and a quiet, smooth transfer.

The lift system was built on a 2' square base made from a 1/4" steel plate. A 44" x 2 1/4" steel pipe ex-tended from the base, with three gussets providing the rigid stand.

The lift mechanism was 6 feet tall and built from 1 3/4" steel pipe with a rounded plug at the bottom, providing a smooth pivoting point.

The lift arm was built from a solid 1 1/4" shaft with a 20-degree bend to keep the angle of motion in a more fixed position during lifting. The adjustable arm was inserted into the 1 1/2" pipe connected to the upright standing frame. The hydraulic cylinder was a stan-dard piece of durable medical equipment, therefore meeting safety standards.


Figure 18.2. Trailer Mounted Personal Lift Transfer System.


REMOTE-CONTROLLED MOTORIZED TOY VEHICLE

Designer Team: Delmer Brower, Dominic Florin, Craig Peck Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory

Supervising Professor: Dr. P. Thomas Blotter Department of Mechanical and Aerospace Engineering


INTRODUCTION An inexpensive simple kit was developed to modify a toy vehicle to be operated by remote control. It was designed for a child with cerebral palsy. Toy vehicles on the market need major modifications both for the safety of the child and the addition of the remote con-trol. The main modified components of this project are as follows:

• New safety harness

• Better roll bar

• Motor to control steering

• Motor to control speed

• Relay to control stop/start

The modified toy in shown in Figure 18.3.

SUMMARY OF IMPACT The major goals included the following:

• Safety for the child

• Easy and inexpensive modifications for parents

• Parent control of vehicle

• Enjoyable interface for the child

A kit was designed to utilize a remote control to oper-ate servomotors similar to a remote-controlled air-plane. A safety harness and larger roll bar were

added to the vehicle. An additional modification was made to enable the child to use the steering wheel without interfering with control of the car.

The kit includes complete instructions and all neces-sary parts to accomplish the modification or informa-tion on where to obtain parts.

TECHNICAL DESCRIPTION The modification involved converting a remote signal to enable the parent to steer, start/stop, and change speeds on the toy vehicle. Most remote devices (and the one chosen for this project) come with two small servomotors. Using mechanical switching, the gas pedal and the gears are operated by one or both of these servomotors.

Through preliminary tests, the torque required to turn the car was determined to be 250-ounce-inches. The size of the servomotor and its connection to the vehi-cle were designed accordingly. Utilizing a four bar linkage, the rotation of the servomotor was trans-ferred to the steering column.

For safety, the degrees of freedom on the steering col-umn were limited to plus and minus 30 degrees. This provided a large enough mechanical advantage to overcome this high torque with a smaller servomotor.

To meet the needs of the child with limited motor con-trol, a larger and more secure roll bar was added along with a safety harness to provide the child with needed support.

The final cost of the kit was approximately $270.


Figure 18.3. Remote-Controlled Motorized Toy Vehicle.


THE SIGHTSEER: ADAPTED OFF-ROAD VEHICLE Design Team: Casey Jensen, Kevin Geddes, Jim Nightengale

Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professors: Dr. Ralph Haycock, Manufacturing Engineering Advisor

Mechanical and Aerospace Engineering Department Dr. Clair Batty, Mechanical Engineering Department Head

Mechanical and Aerospace Engineering Department Utah State University Logan, Utah 84322

INTRODUCTION All-terrain vehicles (ATVs) are not designed for per-sons with disabilities to use safely. A prototype was developed to allow an individual with limited use of his limbs to operate safely an off-road vehicle.

SUMMARY OF IMPACT The Sightseer is an off-road vehicle designed to be op-erated by a person with a disability or any individual who would prefer a 4-wheel drive ATV with addi-tional safety features such as a four-way seatbelt har-ness system, roll cage, and safe return steering. The Sightseer vehicle is fully controllable by a person with limited use of one hand. Further testing is needed to determine whether a person with quadriplegia would be able to operate the steering controls if a joystick controller were provided.

TECHNICAL DESCRIPTION Design criteria were that the Sightseer be:

• Be accessible for entry of a person in a wheel-chair;

• Be safe and durable, with restraints and a roll bar to protect the driver;

• Be reliable, reducing the possibility of breakdown so that the user would be stranded;

• Have four-wheel drive;

• Have simple controls and few complicated parts.

• Have a top speed between 10 and 15 mph for safety; and

• Be designed to climb a 30-degree incline.

A 10 hp Briggs and Stratton gas engine was used to power the Sightseer. Two hydraulic motors were used to provide variable torque output and skid steer. The steering was designed so that if the hand control is released or centered, the vehicle will come to a stop. The vehicle has an electric start and is run by two lev-ers, which fit in one hand.

The vehicle is equipped with a harness over both shoulders and a lap belt to hold the user in a comfort-able, safe position. The seat is padded and has a high back for upper trunk support. Four chains were util-ized for the power and the steering, thereby enabling the operator to return for assistance if one chain were to break. Standard-sized ATV tires were used for easy replacement. The chains and all other moving parts are protected from accidental contact for safety.

A safety training session was planned and offered to the user.


Figure 18.4. Off-Road Vehicle for a Person with a Disability.


CHILD’S JOYSTICK-CONTROLLED GO-CART Designer: Justin Patton

Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professors: Dr. Beth Foley, CCC-SLP

Center for Persons with Disabilities Ms. Amy Henningsen, OT

Center for Persons with Disabilities Utah State University Logan, Utah 84322

INTRODUCTION Many children with physical disabilities cannot eas-ily operate standard motorized vehicles. Motorized vehicles adapted for use with a joystick control cost up to twenty times more than standard models.

The purpose of this project was to design a safe inex-pensive joystick-controlled motorized go-cart for a 6-year-old boy with motor impairment due to spina bi-fida. The child had a cart that had been adapted from a standard type vehicle, but it was difficult for him to operate, and the cart would not operate on the lawn area around his house. Furthermore, the seating sys-tem on his cart did not provide him optimal support and its long wheelbase resulted in poor maneuver-ability.

SUMMARY OF IMPACT Many youths with a range of cognitive or motor im-pairments could utilize an affordable, attractive form of independent mobility. There are several benefits from using this type of device, including the devel-opment of visual and motor skills, increased social activity, and outdoor recreational opportunities from which children with disabilities are often excluded.

The go-cart fabricated for this project incorporated many important safety features including a seat belt system, a foam wrapped roll-bar, a free floating front axle, and a low center of gravity.

TECHNICAL DESCRIPTION The main objective of this project was to enable any-one, including persons with limited mechanical skills, to construct a high quality, low cost, joystick-controlled go-cart using recycled equipment. Most of the basic components of the go-cart were taken from

motorized wheelchairs that had been discarded or outgrown by their operators. Design requirements in-cluded a short wheelbase for good maneuverability, a low center of gravity to compensate for the short wheelbase, and a seating system that would provide the operator with total support for his torso and legs.

The front wheels were extended 5", enabling the seat to be positioned in a safe operable position. Chrome rectangular tubing (3/4" x 1 1/2") was welded from the lower battery frame to the front axle. A solid shaft was fitted into the original frame pivot point and cov-ered with a chrome pipe for aesthetic value.

A child-carrier seat from a bicycle was adapted to provide added support to the user’s torso and legs. Half-inch closed cell foam padding was used to cover the seat, back, leg, and footrest areas.

The seat angle was set as the child sat in the cart while accurate measurements were taken. A front bumper was then added to give additional protection to the child and the go-cart framework.

Because this go-cart may be constructed from parts obtained from older motorized wheelchairs, which are often available at a low cost, the total cost of a similar project may range from only $200 to $500.


Figure 18.5. Child’s Joystick-Controlled Go-Cart


WHEELCHAIR DYNAMIC SEATING SYSTEM

Designer: Gary Malmgren Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory

Supervising Professors: Dr. Beth Foley, CCC-SLP Center for Persons with Disabilities

Dr. Paul Wheeler Electrical and Computer Engineering


INTRODUCTION Over two million Americans suffer from a debilitating condition known as decubitus ulcers or pressure sores. The sores occur as a result of prolonged pres-sure in the seating area. Individuals who use wheel-chairs are susceptible to them, especially if they are unable to make natural, manual shifts of their own weight.

The goal of this project was to create a dynamic seat-ing cushion to prevent pressure sores by alternating the air pressure in the cushion. The seat is designed to assist the natural shift of an individual, thus reduc-ing pressure between the individual’s buttocks and seating area, and facilitating blood flow through a pulsing action of high versus low pressure. This theoretically alleviates the problems of constant pres-sure experienced by individuals with limited move-ment utilizing wheelchairs. The completed prototype will provide a platform for further investigation of the project’s efficacy.

SUMMARY OF IMPACT In the sitting behavior of persons without a disability, there is frequent weight shifting from side to side and from front to back, which occurs unconsciously. This dynamic seating system would help one with a sig-

nificant motor impairment to simulate this natural weight-shifting pattern. Automatically controlling airflow throughout the cushion provides constant changes in the seating position for the individual. The programmable flow of air throughout the cushion acts as a natural shifting process, which helps allevi-ate constant pressure on certain points on the but-tocks most vulnerable to the development of pressure sores.

TECHNICAL DESCRIPTION To obtain a suitable design for this project, a dynamic cushion, designed by Roho, Inc., that provides an in-dividual with the lowest pressure differential be-tween the cushion and the posterior of the user was studies. Design specifications were then given to Roho employees, who produced the prototype. The new cushion has 90 separate air compartments in 9 different rows, divided in the middle of the cushion, resulting in 18 different controlled rows.

A diagram showing the pneumatic plumbing of the cushion is presented in Figure 18.6. A 12-volt pump provides the air pressure needed. A micro-controller controls the mechanical and electrical system.


9Intake

Exhaust

8Intake

Exhaust

7Intake

Exhaust

6Intake

Exhaust

5Intake

Exhaust

4Intake

Exhaust

3Intake

Exhaust

2Intake

Exhaust

1Intake

Exhaust

17Intake

Exhaust

14Intake

Exhaust

15Intake

Exhaust

16Intake

Exhaust

13Intake

Exhaust

12Intake

Exhaust

11Intake

Exhaust

10Intake

Exhaust

18Intake

Exhaust

Exhaust Manifold

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

SIntake

Exhaust

Intake Manifold

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

SIntake

Exhaust

Rotary VanePump(Electric)

PressureSensors

Figure 18.6. Mechanical Diagram.


THREE-WHEELED HAND POWERED CYCLE Design Team: William Ashworth, Shayler Backlund, Andrew Browning

Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professor: Dr. P. T. Blotter Mechanical Engineering Department,


INTRODUCTION A three-wheeled hand-powered cycle was designed to provide riders who have motor impairments with an affordable cycle that requires only the use of the upper body.

SUMMARY OF IMPACT Adapted cycles are typically unattractive, heavy, and overprotective. A cycle was designed to be easy to use, lightweight and fun. The design provides safe, affordable recreational exercise to individuals with paraplegia or other lower extremity disabilities.

TECHNICAL DESCRIPTION The cycle utilizes a standard tricycle configuration, is hand powered (cranked) with an internally geared, chain-driven mechanism connected to the front wheel and mounted directly in front of the rider. Steering is controlled using the same crank mechanism that powers the cycle. Braking is accomplished via front wheel reverse cranking.

The frame consists of a triangular main section and a rear suspension wishbone made of 6061 aluminum. The frame is designed to support a rider weighing up to 300 pounds under normal riding conditions. No-table frame components include a full seat in the re-cumbent position, standard bicycle headset, ergo-nomically correct hand cranks, and a rear shock ab-sorber. Other designs are available on the market, but

are prohibitively expensive and do not include a sus-pension system.

To ensure safety, a chain guard was placed over the drive system. This cranking system is designed to collapse under the weight of the rider in the event of a severe collision. A leg cross brace was provided for maintaining leg positioning.

The down tube has padding to protect the rider from leg bruises. The cycle also has reflectors. The use of a helmet is strongly recommended for all users. A dia-gram of the design is shown in Figure 18.8.

Figure 18.7. Three-Wheeled Hand Powered Cycle.


Figure 18.8. Three-Wheeled Hand Powered Cycle.


DUAL ADAPTIVE RECUMBENT TRICYCLE Design Team: Todd Lawton, Spencer Allen, Jason Eastman

Client Coordinator: Mr. Rick Escobar, USU AT Development and Fabrication Laboratory Supervising Professor: Dr. P. T. Blotter Mechanical Engineering Department


INTRODUCTION The Dual Adaptive Recumbent Tricycle (DART), a three-wheeled tandem bike, was designed to provide stable riding for two. The rear rider cranks with his or her arms while the front rider steers and pedals.

SUMMARY OF IMPACT The DART is a tricycle that allows two riders to travel together. The rear rider may have any level of ability. He or she may crank with his or her arms or just ride along; he or she is not required to balance or control the cycle.

TECHNICAL DESCRIPTION This tricycle was built in a tadpole configuration, with two front wheels providing the steering, and the rear wheel providing the power. It was designed to be recumbent, with full seats to support the riders and provide greater comfort.

The frame and seat of the cycle were assembled from 6061-T6 aluminum with an expected life of 20 years. To ensure continued usability, the cycle was con-structed using as many standard bicycle components as possible, including such items as brakes, wheels, derailleurs, and cranks.

To ensure safety, guidelines from the American Soci-ety of Mechanical Engineers Human Power Vehicle competition were followed, with exception of rollover

protection. This was considered to be unnecessary because of the recreational, low-speed nature of the project.

There are similar recumbent designs on the market. However, their costs are prohibitive for the average consumer. Also, current designs on the market do not provide the person in the rear position the capability of cranking with his or her arms.

Figure 18.9. Dual Adaptive Recumbent Tricycle.


Front Viewof SteeringMechanism

Figure 18.10. Dual Adaptive Recumbent Tricycle

247

CHAPTER 19 WAYNE STATE UNIVERSITY

Departments of Physical Medicine and Rehabilitation, and Mechanical Engineering

261 Mack Blvd Detroit MI 48201


Bertram N. Ezenwa, Ph.D. (313) 993-0649 [email protected]


WHEELCHAIR MOUNTING CLAMP FOR A LAPTOP COMPUTER

Designer: George Gauchey and Robert Lambert Supervisor: Dr. Bertram N. Ezenwa

Department of Physical Medicine and Rehabilitation, and Mechanical Engineering, Wayne State University Detroit, MI 48201

INTRODUCTION Computer clamps for persons who use laptop com-puters while seated in wheelchairs are generally de-signed for specific wheelchairs. Thus, when users re-place their wheelchairs the cost of a new clamp may be problematic. A laptop mounting device was de-signed for use on wheelchairs with rectangular seat base support.

SUMMARY OF IMPACT The client needed a sturdy, economic, and safe method of mounting a laptop computer directly to a wheelchair. The intent of this project is to design a mount that will accommodate a multitude of wheel-chair styles. The mount could also be used for attach-ing communication systems and other devices to hospital beds or floor-mounted tables. This technol-ogy may be used in the home, office, and automobile for attaching various items to chair frame structures.

TECHNICAL DESCRIPTION Design requirements were that the device:

• Be easy to manufacture;

• Be interchangeable from powered to non-powered chairs;

• Be designed for chairs with rectangular tubing frames;

• Be easy to assemble;

• Not require alteration of wheelchair seating material;

• Maintain computer positioning relative to the client regardless of chair tilt;

• Be manufactured from a lightweight, easy-to-machine material.

The design incorporated a wrap-around clamp fix-ture (see Figures 19.1 and 19.2). The wrap-around was sectioned into a three-piece unit with a split top. Figure 19.2 is a graphic representation of the clamp-ing system.

The exploded view (Figure 19.2) indicates all compo-nents required to manufacture and to assemble the clamping fixture. The fixture consists of a Jaw (1), Plate (2), Jaw (3), Plate (4), and eight ¼ - 20 cap screws of various lengths. Table 19.1 provides a breakdown of component costs on a prototype run compared to a batch run. The cost of the part when produced on a large production run will be significantly less than shown here. The costs shown are estimates for pro-duction. However, all materials and machining were donated for this project.

Aluminum was selected for construction material be-cause it is strong, ensuring safety and reliability, and lightweight, so that it will not add excessive weight to the chair. It is also easy to machine, which will help maintain lower production costs. For this prototype, conventional machining methods were used. In mass production, components could be machined in batch production, or basic shapes could be extruded or die cast then, machined.

Chapter 12: Wayne State University 249

A static analysis of the system revealed a safety factor of 23. Therefore, the chance of failure is remote. In addition, the AL 5052 material chosen has a yield strength of 27 kpsi and a tensile strength of 34 kpsi. In all evaluations of the system, the maximum shear stress theory was applied to determine failure and safety factors. No changes in material were required.

System testing was performed by mounting the sys-tem to a stationary tube and by performing a pry evaluation to determine if the device yielded or loos-ened. Pry evaluation consisted of applying an exter-nal load at the clamp mount surface. During testing, no failures were observed.


Figure 19.1. Wheelchair Mounting Clamp for a Laptop Computer.


3

1

2

4

4

Figure 19.2. Diagram of the Wheelchair Mounting Clamp for a Laptop Computer.

Table 19.1 Parts and Projected Costs for the Wheelchair Mounting Clamp for a Laptop Computer.

Part Number 1 Piece Production Run * 10 Piece Production Run *

Jaw (1) $60 $30

Plate (2) $20 $10

Jaw (3) $40 $20

Plate (4) $40 $20

¼ - 20 Cap Screw $5 $5

Total $165 $85


ADJUSTABLE PLATFORM FOR AUGMENTATIVE COMMUNICATION DEVICES

Designer: Jean Khalife and Todd Desantis Supervisor: Dr. Bertram N. Ezenwa

Department of Physical Medicine and Rehabilitation, and Mechanical Engineering, Wayne State University Detroit, MI 48201

INTRODUCTION Augmentative communication devices are useful tools for persons with disabilities at work, leisure, and school. The devices are normally situated in a fixed location. In some cases, the operator may need to be mobile while having access to them. The adjust-able platform for augmentative communication de-vices made it possible for a person who has decreased fine motor control due to cerebral palsy (CP) to con-tinue his employment in an environment that requires him to move his communication system from place to place from his wheelchair.

SUMMARY OF IMPACT This adjustable platform was designed to help a cli-ent with CP to easily and quickly move his augmenta-tive communication devices from one workplace to another. Ability to adjust the platform from 0 to 45° allowed the client to use various types of augmenta-tive communication systems, including laptop com-puter-based types. The platform’s height and width are adjustable to allow for use from wheelchair or while standing. The platform is easy to use with a quick setup time and can be disassembled to fit in small areas for storage. The casters allow portability with a simple anchoring system. All materials used are recyclable and of high quality for increased life and durability. The system will help the client or any individual with CP to obtain and maintain employ-ment.

TECHNICAL DESCRIPTION Specifications were that the platform:

• Allow the user adjust its height and the angle;

• Support a variety of communication devices, including laptop computers;

• Support a variety of weights;

• Be stable, with the ability to withstand offset loading with minimal vibration;

• Tilt up to a 45° angle to prevent light reflection on the screen;

• Be made of non-slip materials;

• Enable the user to move from room to room with devices attached;

Figure 19.3. Photograph of the Adjustable Plat-form For Augmentative Communication Devices.


• Be easy to use and allow for quick assembly and disassembly;

• Be portable, allowing easy movement to differ-ent locations and floor types;

• Be strong and durable;

• Fit in a small area after being disassembled; and

• Be economical.

Design Description Detailed drawings were generated using AUTOCAD software. The design consists of a base that is made from 2” x 2” steel tubes. One left and one right foot extend telescopically from the body. The feet and cen-tral extensions are made from 1.75” perforated square steel tubes. The platform is made from 3/4” particle-board Formica and is covered with a non-slip pad. The platform is mounted on a “T” shaped structure made from 2” x 2” steel tubes with hinges. All tubes have 1/8” wall thickness. Adjustments can be made in four different directions. The foot extensions tele-scope left and right to fit different sizes of wheel-chairs, while the central extension moves vertically for height adjustment. In addition to angle adjust-ment, the platform telescopes in and out to compen-sate for the difference in user sizes. The client re-quired a tilting angle up to 45°. With the use of the friction hinges, the angle exceeded 60°. The friction hinges can support up to 45 lbs.

As mobility was of great concern, the system was mounted on four rubber wheels. Two of the wheels can twist at 360° and are equipped with strong brakes. The two other wheels are straight to facilitate steering, minimize drift, and increase stability. Pins (7/16”) are used to hold the components in the de-sired position. Finally, the system was sprayed with a heavy industrial paint coat to prevent rust and im-prove its appearance. The chosen color, antique white, matches almost any furniture color.

Manufacturing and Assembly After accomplishing the detailed drawings and com-pleting the parts list, the system was constructed. The square tubes were cut to the desired sizes at a 45° an-gle using an automatic hydraulic saw. Light filing was necessary to eliminate the burrs and to allow

close alignment of the tube edges for proper welding. The tubes were aligned and welded together accord-ing to the designed shapes. To obtain a smooth sur-face, a grinding process was necessary to even the edges. Drilling for the holding pins and tapping for the mounting hinges were the last machining proc-esses. The system was then assembled and subjected to a bench test to evaluate its function.

While the system was being painted, the wooden platform was assembled. One stainless steel hinge was used across the platform to achieve the tilting op-tion. Two adjustable friction hinges hold it at the de-sired position. After all components were painted, the wheels were mounted. Finally, the system was evaluated.

Bench Test and Product Evaluation Initial design evaluations revealed concerns with cer-tain areas of the platform framework, which required stiffening to reduce the possibility of vibrations dur-ing operation. Reinforcements were added to distrib-ute the loading, thus eliminating the problem. After assembly, one of the four casters was noted to be not touching the ground. This misalignment was due to welding affection. Components were heated and ad-justed to minimize the offset. The casters were brought to an acceptable planar to eliminate the prob-lem. Heavy loads were placed on the end of the plat-form to simulate people leaning their partial or entire weight on the platform. There was negligible defor-mation.

Ease of adjustment of the framework was an impor-tant concern. Filing and grinding were necessary in some areas in order to improve telescoping smooth-ness. The last test included communication device re-tention to platform at maximum adjustment. Several types of laptops and devices were placed on the sur-face while it was tilted to an angle of 60°. The devices remained in place and no problems were exhibited.

It is estimated that the system will cost $492.85. How-ever, area companies donated all the parts for the pro-ject.


MOUTH STICK DOCKING STATION Designer: Tony D. Smith and Ibrahim A. AL-Homoudi

Supervisor: Dr. Bertram N. Ezenwa Department of Physical Medicine and Rehabilitation, and Mechanical Engineering,

Wayne State University Detroit, MI 48201

INTRODUCTION Some patients with quadriplegia use a mouth stick to change channels on their televisions. The mouth stick requires a receptacle for storage when not in use. The mouth stick docking station is a device used to hold a mouth stick for a patient with quadriplegia. The design is flexible, adjustable, comfortable, and re-liable. It enables the patient easily to grasp and re-lease the mouth stick.

SUMMARY OF IMPACT The design is adjustable and easy to use, thereby free-ing caregivers and enhancing the patient’s independ-ence. The system is portable and adaptable for vari-ous bed units, as well. With the unit mounted to a headboard, the patient still has freedom and space to carry out other activities. The unit is easy to reposi-tion for transferring patients in and out of bed.

TECHNICAL DESCRIPTION The mouth stick docking station is made of machined aluminum alloy attached to a flexible gooseneck. The gooseneck is mounted to a hospital bed frame using a triangular flange. The system is designed to prevent the mouth stick from falling out of place after its re-lease.

The choice of aluminum alloy enabled the reduction of the amount of force applied while holding the mouth stick. The system is illustrated in Figure 19.4.

Testing and Reliability: Tests were conducted to verify the success rate of adequately placing the mouth stick on the docking station. Each result was compared against a wooden docking station model with a success rate of 15 out of 20 attempts. The results of the tests indicated a suc-cess rate of 19 out of 20 trials. The increase in success rate may be attributed to the wider v-shaped alumi-

num prototype. Aluminum was chosen over wood for manufacture because the use of a wider wooden slot would jeopardize the structural integrity of the docking station. Although the wooden docking sta-tion integrity could be improved through greater bulk, increased mass may cause a large bending moment on the flexible gooseneck.

Figure 19.4. Mouth stick Docking Station.


Calculations for reducing the volume were made for the surface areas V1, V2, and V3. Weight reduction was achieved by machining off these materials. Three areas of reduction were considered, the two corner sections next to the taped hole and the bottom outer corner, as seen in Figure 19.7.

The total cost of the project was $115.89.

DockingStation

FixedAttachment

Gooseneck

Wooden Concept

Figure 19.5. Wood Concept for the Device.

Aluminum Concept

Figure 19.6. Aluminum Concept for the Device.

V1

V2V3


LAPTOP COMPUTER CARRYING SYSTEM Designer: Nail Azar, and Paul Jacovac



INTRODUCTION This project was developed for an adult with cerebral palsy who uses a laptop computer for communica-tion. The patient is ambulatory and needed more mo-bility at his job. His augmentative communication system must be available to him at all times. There-fore, a comfortable, ergonomically correct method for the safe transport of his laptop computer without his having to disassemble and place it in a carrying case each time is optimal.

The device is positioned in front of the patient to en-able him to see the monitor and access the keyboard with his hands. Frequently, his job requires him to guide two individuals with cognitive impairments around the store by holding their hands. The work-ing environment for his main activity has a tiled and carpeted floor with a small step separating the two. The aisles are large enough for adequate turn space.

SUMMARY OF IMPACT This laptop computer carrying system enables the cli-ent to have his communication system at his disposal at all times. The client can use it to safely transport his laptop computer in an ergonomically correct way to a variety of settings in his environment. The device was designed to be in front of him, while still permit-ting the freedom his hands to do other necessary operations. The design folds up well and is light enough to transport easily.

TECHNICAL DESCRIPTION Design considerations included that the device be lightweight, safety, compact size, height adjustability, ease of assembly and disassembly, ease of rolling ri-gidity, and static stability. The design consisted of crevices rather than pins for the main body. Support was added, as well as a wedge for mobility along with a twist key for simplicity. These criteria were taken and combined into a package that would fold up easily.

The material used was “off the shelf” lightweight aluminum. The two cross members on the base were for rigidity and a foundation for the support and main shaft. The targeted total weight was less than 20 pounds. The final product weighed 17.5 pounds. This design was viewed using CATIA, and further analysis showed that it was both statically and dy-namically rigid.

Performance Evaluation After completion, the system was assembled and dis-assembled repeatedly to ensure capability, repeatabil-ity, and ease of assembly. The device was rolled over concrete, carpeted floors, and tiled floors to guarantee dynamic rigidity and stability.

Tests revealed design specifications were met and sat-isfied the client’s needs.

Cost Analysis

Description Cost

Swivel Wheels 2” 51mm $14.36

4” Heavy Duty Strap Hinge $1.87

1” Narrow Non Removable Hinge

$1.53

Light “T” Hinge $1.47

1/8”X1/2”X4’ Aluminum Angle

$9.97

1/8”X1/2”X8’ Aluminum Angle

$19.85

1”X1/16”X48” Aluminum Square


Square

1”X3/4”X4’ Aluminum Square

$15.47

1/8”X36” Rod $1.47

Total $72.82

The estimated material cost of the project was $72.82

Figure 19.8. Laptop Computer Carrying System.


LOWER EXTREMITY EXERCISE SYSTEM Designer: Aaron Adams, and Tracey Matlock



INTRODUCTION The purpose of this project was to build a device to stimulate the lower extremities of a patient who had a stroke. The caregiver requested mechanical stimula-tion to weakened motor joints.

SUMMARY OF IMPACT The patient regained function on both sides. It is an-ticipated others could benefit from this mode of accel-erating stroke recovery.

TECHNICAL DESCRIPTION Various options were considered, including revising an existing massage system, such as, the “Foot Fixer” or the type of pad used on a chair. However, the sys-tem inputs could not be controlled and the inputs were not repeatable. The decision was to design a sys-tem with controllable frequency and vertical pitch on which the patient’s feet rest. By pulsating the pa-tient’s feet with vertical amplitude at variable fre-quency, pulses from the instrumentation transmit through the motor joints.

The original design called for a stationary platform on a set of turning rods instrumented with small bumps to make contact with the platform. During op-eration, these bumps would transmit pulses to the platform, which would then be sensed by the pa-tient’s feet.

To accommodate the demand for a robust system, the design was converted to a camshaft like design. The platform is made of metal. The design consists of two shafts, four brackets, four rollers (disks), four roller bearings, and two steel plates. As the shafts are timed accordingly, inputs can be controlled.

A cam or roller had to be set 0.125 inch off center to rotate about a shaft to enable the vibrating platform n to move vertically with a pitch of 0.125 inch. Initially, there were two shafts, 1.125 inches in diameter. The

ends of the shafts were turned down to 1" to fit the couplings for the cog gear. The vertical motion was created by four simple rollers, 2.5 inches in diameter. There was a hole drilled into the rollers to accommo-date the shaft. The hole drilled was 1.125 inches and was offset 0.125 inch from its center. The purpose of this offset was to create the elliptical motion required to obtain the vertical motion for the platform.

The four rollers were drilled and tapped along the outer perimeter to enable them to be fastened to the shafts. Also, these holes facilitated the indexing of the rollers to ensure that they line up perfectly. To al-low easy rotation, bearings were used. The four bear-ings were 1.125 inches in inner diameter, 1.5 inches in outer diameter, and 0.5 inches thick. To support the bearing and the rod, a bracket was fabricated. The bracket began with 3.5 inch by 5 inch by .5-inch stock. Then all four pieces of stock were simultaneously ma-chined down on a milling machine. The brackets were then drilled.

To ensure the four holes lined up perfectly, the brack-ets were again drilled and clamped together. The parts were then assembled to check fit. The bearings were not press fitted into the brackets. Instead, the

Figure 19.9. Photograph of Lower Extremity Exer-cise System.


bearings were secured using setscrews. There were two setscrews holding the bearings in place. To fasten the brackets to the plate, the eight holes were first drilled into the plate. Then the brackets were put in place and marked for accurate hole locations. Next the cog gears were added to one end of each shaft. The cog was tapered to create a press fit when tight-ened with a screw to the coupling. The bracket-to-plate hole locations were determined from the dis-tance center to the center of the cog and the timing belt. Once the locations were marked, the holes were drilled and tapped.

Subsequently, the platform was ready to be fully as-sembled. First the roller was secured to the shafts, lin-ing up all the holes. Then the bearings were placed on the shaft about 9 inches apart. Once the bearings were in place, the brackets were secured. The brack-ets were tightened to the bearings using setscrews. Finally, there were two shaft assemblies. Again the assemblies each consisted of the shaft, two bearings located approximately 9 inches apart, and two brack-ets, which held the bearings in place. These assem-

blies were then secured to the plate using flat -head screws. The mechanical displacement platform was then mounted to the control system. The mechanical platform was fabricated from donated materials. The two shafts, the plate, and the four rollers were also donated.

DRIVE MOTOR AND MOUNTING PLATFORM The plywood used to support the system was stan-dard ¾ inch. The platform has the dimensions of 18 inches by 32 inches and four industrial strength wheels mounted at each corner. The motor was a 90-volt Dayton ¾ HP motor with a Dayton variable speed controller. The motor was wired for an input of 120V to enable use in household applications. The patient or an caregiver can vary the 120V input to the controller by changing the voltage going into the mo-tor through a calibrated turning knob. The greater the voltage, the faster the plate vibrates.

261

CHAPTER 20 WRIGHT STATE UNIVERSITY College of Engineering and Computer Science

Department of Biomedical and Human Factors Engineering Dayton, Ohio 45435-0001


Chandler A. Phillips (937) 775-5044 [email protected]

David B. Reynolds (937) 775-5045


BILATERAL ACOUSTIC TRAINER Student’s Names: Chad Bogan, Karen Fox, Michael Papp

Client Coordinator: Ms. Elaine Fouts Gorman Elementary School

Supervising Professor: Dr. Chandler A. Phillips Department of Biomedical and Human Factors Engineering

Wright State University Dayton, Ohio 45435-0001

INTRODUCTION The Bilateral Acoustic Trainer is a keyboard redes-igned to teach preschool children proper use of an in-strument and to encourage bilateral movement in children who tend to use only one hand. The chil-dren become more disciplined since they must prop-erly play with the toy for the keyboard to respond to their actions. Also, children with limited use of one or both arms are more inclined to use the less domi-nant arm and hopefully increase dexterity in the weaker arm. The instrument is also adaptable for children with hearing impairments to enable them to seek enjoyment from a musical instrument, as well.

SUMMARY OF IMPACT The keyboard accommodates children who have lim-ited use of only one of arm such that they are required to use their non-dominant arm. It operates only when the child is using both hands with feet properly placed on the activation pad. In addition, it discour-ages children’s abuse of the keyboard. It automati-cally shuts off if being used improperly or if the child

steps off the floor pad.

The keyboard incorporates a switch, which allows the child to use only one hand. The keyboard case and keys were redesigned to withstand environ-mental stresses. The keyboard is functional for a va-riety of operators. It includes a visual display for children with hearing impairments. An additional switch, solely for the teacher, allows her to deactivate the bilateral component of the keyboard for children with use of only one arm.

TECHNICAL DESCRIPTION The floor activation pad acts as a power supply switch for the keyboard. The pad has an upper and lower plate made of plywood. A metal plate is lo-cated in the center of the plywood plates, which may be pressed together, causing the metal plates to make contact, thus closing the switch. The no-spring floor pad does not use springs, as it relies on the flexibility of the upper plate to allow the metal plates to make contact.

Figure 20.1. Bilateral Acoustic Trainer.

Chapter 20: Wright State University 263

The anti-bang device was designed to deactivate the system when the keyboard is struck with excessive force. The teacher must reset it. This feature is con-trolled by a simple set of switches, which rely on a linear spring to close a switch only when a preset force (determined by the spring coefficient) has been exceeded.

The keyboard is divided into fourths (as shown in Figure 20.1), with two sections being distinguished by green and two sections by orange. To satisfy the cir-cuitry of the bilateral control, a key from each green group has to be played simultaneously, or a key from

both orange groups must be depressed simultane-ously.

The logic behind the Bilateral Acoustic Trainer is shown in Figure 20.4. The decade counter is used as a toggle switch based on a signal being received from the bilateral on/off button. The OR gate closes the re-lay when two like color keys are pressed, when but-tons of different colors are pressed, or if the output of the decade counter is high, indicating the bilateral aspect of the keyboard has been deactivated. Figure 20.6 displays a portion of the existing keyboard, which illustrates the modification of the existing key-board circuitry necessary to detect when one or more keys in a group is being pressed. This is equivalent for a given color group of keys. The output increases for each progressive key on the keyboard. In essence, the pads, which are closed by a conductive plunger when a key is pressed, are shorted together to ensure current flow if any pad is closed. The diodes enable the distinction between one key in a group being played versus all the keys in the group being played simultaneously.

Upper Conductive Plate

Upper PlatformSpacer

Triangular Strip

Lower Conductive Plate

Lower Platform

Lead Wires

24.00 2.00.750

Figure 20.2. The No-Spring Floor Pad.

Piston

Upper Metallic Plate

Plastic Spacer Plate

Lower Metallic PlateWires

Spring

Figure 20.3. The Anti-Bang Switch Acting as a Force Transducer.


A continuity checking circuit senses when a key or

1

32

R

C

Grn. 1 Grn. 2 Orng. 1 Orng. 2

(Input high if key fromgroup depressed)

From keydetectioncircuits

From ButtonDetector

(high if buttondepressed)

5 Volts

To Speakers

Normally open Relaythat closes onlywhen final OR gategoes high. Closingallows signal toSpeakers

Figure 20.4. Logic of the Bilateral Control.

R

81

5V

Figure 20.5. Modification of Existing Keyboard.


The transistor is necessary because the diodes drop the voltage enough so the Schmidt trigger does not trigger when placed at the high end of the first resis-tor. The capacitor provides a small amount of de-bouncing to the circuit. The diodes are necessary to detect if only one key in a group is pressed, as shown in Figure 20.5. Since the Schmidt trigger inverts, the inverter supplies the entire detection circuit its de-sired output characteristic, namely high when a key is pressed. Conversely, the opposite is true when the desired output characteristic is low.

Figure 20.7 shows the quad analog switch in this cir-cuit used as a buffer, as the hex inverters could not provide sufficient current to completely activate the switch. There are four of these circuits, one for each group of keys. Since the input is high when a key is

pressed, the output is five volts to the circuitry con-trolling the visual display unit. The visual light dis-play shown in Figure 20.1 consists of four groups of lights corresponding to the four groups of keys. When a key is depressed, the corresponding column of lights is illuminated row by row, upward from the bottom. When the key is released, the lights go out. The cycle begins again when the key is pushed. The circuitry for the light display is controlled by a 555 timer that sets the speed for the LED activation. A decade counter is used in conjunction with the 555 timer to light them sequentially upward from the bot-tom. Transistors are used at the output of the decade counter to increase the current to the LEDs, thereby increasing their brightness.

The total cost of the project was $790.

5V

22k

22k

5V

This switch represents akey or button or agroup of keys. Thecircuit detects closureof his switch

Figure 20.6. Continuity Checking Circuit to Sense when a Key is Pressed.

From key detectioncircuit

(Input high when keyfrom certain colorgroup is pressed)

Quad AnalogSwitch(4016)

Transistorswitchws powerto the displaycircuit

To Loght Display Circuit

Figure 20.7. Quad Analog Switch Used as a Buffer.


ENVIRONMENTAL CONTROL UNIT Designers: Jeff Demchak, Jill Leighner, Jill McCollough

Client Coordinator: Karen Harlow Gorman Elementary School

Supervising Professor: Dr. Blair Rowley Department of Biomedical and Human Factors Engineering


INTRODUCTION An environmental control unit was needed to allow a person with severe cerebral palsy to control his sur-rounding environment. The user is a twenty-four- year-old male with severe spastic cerebral palsy. He uses a wheelchair. He is completely paralyzed, with the exception of the ability to blink both eyes and ro-tate his head about .25 inches to either side. The cli-ent is unable to manually change the channel on his television with a conventional remote due to his paralysis. The client is nonverbal. Consequently, the opportunity to choose or to express his desires has never been available. This project design enables the client to control his television set and two additional electrical devices through the use of a cheek button.

SUMMARY OF IMPACT This environmental control unit allows the operator to actively participate in the surrounding environ-ment and make his own choices, by controlling the television as well as other electrical appliances. This form of interaction with the environment increases the communication level in his home. Having a choice of the four options available to the user at a particular time allows different items to be disabled by the caregivers in case the device is used incorrectly by the client. These options also allow the device to meet the user’s needs in controlling only the options desired or the options that may be handled by the simple turning of a switch. With the built-in variable sequencing rate, the product accommodates different user reaction times. As the user becomes familiar with the device, the rate may be increased. Likewise if the condition of the user becomes more severe, the rate may be decreased.

TECHNICAL DESCRIPTION The unit consists of the following eight components: display case, user button, AC/DC adapter, X-10 modules, X-10 remote, remote extender receiver, uni-versal TV remote, and microprocessor. To operate the unit, the user button and power must be placed into the appropriate jacks; the remote extender receiver must be directed at the TV; and the electrical appli-ances to be operated with the X-10 controls must be turned on and plugged into the modules. The user then determines one of 15 option modes by activating the appropriate switches located above each of the four pictured options. If the switch for a pictured op-tion is activated, then that option is included in the sequencing pattern for selection by the user. Next, the unit is activated with the power switch located in the upper left corner of the display case. The unit then continuously cycles through the selected options, and the operator depresses the button when the desired option is available. The selected option is signaled by the momentary lighting of an LED positioned above each pictured option on the display case. When a choice is activated, the cycle continues until another option is selected.

REDLEDS

SPEED CONTROLKNOBMODE SWITCHES

ON/OFF SWITCH

Figure 20.8. Front view of the Environmental Con-trol Unit


A microprocessor is used for the basic control of this project, specifically the BASIC Stamp II, which has 16 input/output pins. The first four input/output pins, pins zero through three, are used as inputs to control the modes option.

Any of the four possible options can be switched on at any time. Each of the first four pins is connected to a switch that connects the input pin to a high source when switched to the on position.

The microprocessor program notices which of the four switches are thrown or any combination of those switches and activates output pins four through seven, which are connected to LEDs on the display menu, indicating a particular option to be available. For instance, if switches A and C are thrown, the LEDs above options A and C will toggle on and off until a choice is made or until a different mode is ac-tivated, thus allowing the user to expand options. If the user can handle only one option at a time, one switch can be placed in the on position making only that particular option available.

Pin eight is an input pin for an RC circuit. The resis-tance is varied by a potentiometer to form different RC time constants measured by the microprocessor. This potentiometer allows the user or the user’s caregivers to vary the rate at which the options are being scrolled through the menu display, thereby eliminat-ing the problem of having a fixed rate. The potenti-ometer is available on the front of the display case, and the rate can be adjusted by simply turning a knob. The variability of rates is such that the slowest is appropriate for first time users, while the fastest is quick enough for an advanced user.

Pins nine through 12 are used to activate the TV channel up, TV power, turn the first X-10 device on, and activate the second X-10 device, respectively. Pin 13 is used to continuously monitor the user button input. The remaining two pins, 14 and 15, are used to deactivate the first and second X-10 devices.

The total cost of the project is $630.

SOUTSINATNVSSP0P1P2P3P4P5P6P7

VINVSSRES

VDDP15P14P13P12P11P10P9P8

MICROPROCESSORX-10 REMOTELAMP OFF

X-10 REMOTERADIO OFF

X-10 REMOTELAMP ON

X-10 REMOTERADIO ON

X-10 REMOTETV POWER

X-10 REMOTECHANNEL UP

50KPOTENTIOMETER

BUTTONINPUT

ON/OFFSWITCH

POWER INPUT(AC/DC ADAPTER)MODE

SWITCHES

TRANSISTORS

Figure 20.9. Wiring Diagram.


ADJUSTABLE CHAIR HEIGHT Designers: James Marks, Kevin Spicer Client Coordinator: Debbie Accurso

Gorman Elementary School Supervising Professor: Dr. Ping He

Department of Biomedical and Human Factors Engineering Wright State University

Dayton, Ohio 45435-0001

INTRODUCTION This adjustable chair height project was developed to modify an existing wheelchair for a five-year-old child with Arthrogryposis Multiplex Congenita, in-volving fibrous stiffness of one or more joints. The client remains in his wheelchair during the day. Pre-viously, because of the fixed height of his wheelchair, the child had to be transferred to another chair when he wanted to work or play at various stations posi-tioned throughout his classroom.

SUMMARY OF IMPACT The adjustable chair lift raises and lowers the client’s chair to variable heights to accommodate different workstations throughout his classroom. The adjust-able chair height project allows the child to interact in a variety of situations with other children in the class.

TECHNICAL SUPPORT The client’s wheelchair sits approximately 13 inches off the ground. Some of the classroom workstations, a sandbox and workbench, are at a height of 25 inches off the ground, placing them out of the child’s reach when he is in his wheelchair.

The adjustable height chair involves lifting the chair manually with a screw jack, using a hand crank placed on the back of the chair. The chair is mounted to the top plate of the jack by two steel plates. The base of the screw jack is mounted onto a steel plate. The cylindrical base rails of the chair are replaced with rectangular steel rails of the same length. The steel base plate is then mounted on these new base rails. The 90° drill attachment (RAD) is attached to the base of the chair by a bracket. A steel adapter at-taches the 90° drill attachment to the jack. Another steel adapter attaches a universal joint to the opposite end of the drill attachment. The universal joint is

used to compensate for the drift experienced by the jack. One end of a steel rod is attached to this univer-sal joint. Another universal joint drill attachment sys-tem is then attached to the opposite end of the steel rod. A steel adapter attaches the hand crank to the 90° drill attachment. This system, along with the hand crank, is the gear mechanism used to rotate the screw, resulting in a change of chair height.

The hand crank mechanism is attached to the back of the chair by a slide-guide rail system. This system al-lows the position of the hand crank to remain con-stant as the chair moves vertically. The 90° attach-ment, RAD, is attached to the slide-rail system by a bracket. Another steel plate is attached to the lower part of the slide-rail system to add stability. The slide-guide system is attached to the back of the chair by a block made of ¾-inch plywood.

Two struts are used to help reduce the torque needed to raise the chair and provide stability, reducing the side-to-side motion of the chair. The struts are also

Figure 20.10. Scissor Jack Design.


used as a safety measure to control the rate at which the chair is lowered. These struts are attached to the back legs of the chair and rail base by means of a ball-and-socket system.

Two steel rods serve as leg guides at the front of the chair. One end of the rod is placed inside the leg. The opposite end of the rod is attached to the rail base of the chair by a nylon block. This block is designed to allow lateral movement of the rod, compensating for the drift experienced by the jack.

For mobility, four casters are placed at the ends of the base rails. The two front casters are rigid, while the back casters swivel to allow chair rotation. The back casters have a lock system that is implemented when the chair is raised or lowered.

A new footrest was made of ¾” plywood so the child’s feet would not be left suspended from the chair. Nylon bellows are attached to the front legs of the chair, as well as around the shaft and universal joints used in the hand crank mechanism, to prevent children from getting pinched between the guides and the legs of the chair as the chair is raised and lowered.

Execution of the lift is basic. Once the chair is wheeled to the desired table, pushing the tab at the side of the back wheel to the down position locks the back casters, making the chair ready to be raised. Then the person places one hand on the back of the chair to stabilize the person operating the crank and then turning the crank clockwise until the chair is at the desired height. The chair will remain in that posi-tion until the hand crank is used again.

To lower the chair to the original position, one hand is placed on the back of the chair, once again for stabi-lization of the operator, and the crank is turned coun-terclockwise with the other hand. The crank is turned until the chair stops moving. The chair is able to raise and lower within a specified range. It has a mini-mum height of 13 inches, measured from the floor to the bottom of the chair, allowing the chair to be used for the lowest table in the room. The maximum height attainable is 19 3/4 inches, again measured from the floor to the bottom of the chair, allowing the chair to be used with the highest table in the room, 25 inches.

The total cost of the project, excluding the donated manufacturing costs, is $710.

Figure 20.11. Adjustable Height Chair.


MULTI-FUNCTION SPEECH THERAPY APPARATUS

Designers: Jason Brookbank, Michael Eaton Client Coordinator:

Supervising Professor: Dr. Ping He Department of Biomedical and Human Factors Engineering


INTRODUCTION A multipurpose device was needed to aid speech-language pathologists (SLPs) in the treatment of pa-tients with a variety of speech disorders. Speech therapists often use Devices used by SLPs include metronomes, tape recorders, volume indicators, and delayed auditory feedback (DAF) systems. Tape re-corders are used to record a sample of the patient’s speech to examine and store for future use variables, such as breathing rate and articulation. Although standard tape recorders adequately serve this pur-pose, they require constant user interface to control the record and playback of the sample, requiring the therapist to expend therapy time rewinding and lo-cating the sample on the tape. Solid-state recorders such as those used in some answering machines ad-dress these problems, but can only record and play-back finite read-write cycles.

Although there are commercially available devices that measure volume levels, research revealed no prior single self-contained device designed specifi-cally for speech therapy that clearly displayed rela-tive volume levels. Metronomes are commonplace devices that produce a pulsatile sound at a variable constant frequency. There are many types of metro-nomes on the market, but few, if any are designed specifically for speech therapy.

SUMMARY OF IMPACT This multipurpose device will assist SLPs in the treatment of patients with speech disorders.

TECHNICAL DESCRIPTION The Multi-function Speech Therapy Apparatus util-izes a microprocessor to ensure no degradation in the sound quality regardless of the storage time. The met-

ronome used in this project is a simple 555 timer al-lowing for simple on/off switching and simple con-trol rate. The microphone pre-amp in this design is a simple transistor amp, which has the benefits of a single power supply, few components, low power consumption, and a desired built-in +2.5 volt offset. A TDA7052 headphone driver chip is also included in this design since it has the required bandwidth, the power output ability needed, and a single potenti-ometer to control the volume. A LM3914 chip is spe-cifically designed for driving a string of LED’s in the desired manner. This chip takes a voltage input, processes it with a comparator stack, and lights a cor-responding LED based on the input voltage.

This device offers several functions including the metronome, short delay, long delay, and visual feed-back. The metronome function is controlled with the metronome on/off switch and the metronome rate knob. The purpose of the metronome is to help gener-ate a fluid speech rate. The metronome is generated from an audible pulse occurring at an interval set by the delay control knob. The patient will usually say one syllable per beat. Therefore, the delay ranges from one to five beats per second.

The short delay function is controlled with the toggle switch (short delay on/off) and rotary switch (short delay length). The purpose of the short delay is to de-lay the speech of a person from 50 to 250 millisec-onds. This delay period can reduce stuttering. The delays are utilized therapeutically by starting the pa-tient on the long delay and then gradually decreasing the delay as speech improves.


The long delay function is controlled with the toggle switch (long delay on/off) and optionally by the manual Play/Record Control. The long delay can re-cord 16 seconds of speech and play the sample back. When the long delay mode is activated, it will check to see if the manual control is attached. If the control is not present, the MFSTA will automatically start re-cording a 16 second sample. When the buffer is full, the MFSTA will wait approximately four seconds and then play back the sample. Upon conclusion of the playback, the unit will start to record again. If the status of the short delay or long delay modes is changed while the unit is recording or playing back, the mechanism necessitates waiting for the unit to fin-ish the playback before the change occurs.

The visual feedback device (VFD) is activated by the power switch. The VFD has an arc of 10 LEDs, indi-cating the relative volume of the speaker. The indica-tor shows the volume of the speech the user is hearing over the headphones. The LEDs are color- and posi-tion-coded such that green is ideal, yellow being close and red being in the extreme. The left LEDs indicate “too soft;” center is optimal; and right is “too loud.” The threshold knob (calibration) adjusts the sensitiv-ity of the VFD to represent different desired volumes. This device is useful in any case where a second feed-back source is desired.

The total cost of this project is $790.

Headphone 2

Microphone

Headphone 1

Metronome rate

long delay ON/OFF

short delay ON/OFF

System Power

short delay length

Metronome ON/OFF

Volume

Figure 20.12. Diagram of Controls.


AUTOMATIC JAR OPENER Designers: Chong Kim, Rob Short

Client Coordinator: Ms. Donna Harlarcher Fairborn Community Services

Supervising Professor: Dr. David Reynolds Department of Biomedical and Human Factors Engineering


INTRODUCTION A device was designed to automatically open jars . It was designed for a client with scleroderma, a form of arthritis, which diminishes physical capabilities such as gripping. In the process of opening a jar, one must be able to stabilize the jar with enough grip strength to counteract the torque necessary to unscrew the lid. The three main objectives of this design include the vertical mount subsystem, the grip/interface subsys-tem, and the torque input subsystem. The vertical mount subsystem allows for vertical accommodation of various jar sizes. The grip/interface subsystem applies grip to hold various jar materials, provides the necessary counter-torque, and accommodates various jar diameters. Finally, the torque input sub-system applies grip to hold jar lids, provides the re-quired torque, and accommodates various jar lid di-ameters.

SUMMARY OF IMPACT Besides aiding those who suffer from scleroderma, an automatic jar opener would be useful for others who physically struggle to open a tightly sealed jar.

TECHNICAL DESCRIPTION The motorized Open Up Jar Opener manufactured by Appliance Science was the best match for the desired specifications based upon ease of use and manufacturing considerations. This pre-fabricated, readily available, motor-driven unit was a logical choice for use in a comprehensive design. Testing indicates that the device provides ample torque and

the device provides ample torque and can accommo-date a range of lid sizes. Because the device requires a normal force and a gripping counter-torque, the re-maining design considerations focused around adapting this device to the client.

A normal force of at least 50 lbf, but not more than 100 lbf is considered ideal. Also, space specifications are an important factor in the normal force generator. A laboratory scissors jack was used because of space ef-ficiency, fluid motion, and ease of use. The jar grip-ping system needs to be easily aligned under the cone of the opener and consists of employing a high nor-mal force and a friction-enhanced surface (rubber). This system is integrated with the scissors jack by coupling an adapted handle to the labjack power screw.

To obtain enough clearance for this handle, the Open Up is mounted to the labjack, which presses down onto the fixed jar when the crank handle is turned. Under the jar, silicone rubber (coupled with the nor-mal force generated by the labjack) acts to secure the jar. The ½-inch thick rubber mat also absorbs the ex-cess normal force generated as a lid is unscrewed. A 1/8-inch-thick aluminum frame with a Plexiglas door encloses the device. For additional safety, a double strain gage force feedback system is implemented to provide user feedback.

The total cost of this project is $890.


CRANK HANDLE

LOCKING SWITCH

SECURED POWER CORD

OPENING FOR POWER CORD

ALUMINUM FRAME

ZERO ADJUSTMENT

POWER FLIP SWITCH

DIGITAL DISPLAY(MATTERY HOLDER INREAR OF UNIT)

MOTORIZED CONE

FORMICA BASE

FORCE FEEDBACK

FRICTION PAD

ELEVATION INSERT

HINGE FOR PLEXIGLASS DOOR

FLEXIBLE POWER CORD

OPEN UP

LAB JACK

Figure 20.13. Front View of Automatic Jar Opener.


RTA BUS ANNUNCIATOR SYSTEM FOR PERSONS WITH VISUAL IMPAIRMENTS

Designers: Kimberly Clarkston, Bryan Jones, Tariq Sharif Client Coordinator: Jim Fourcade

Miami Valley Regional Transit Authority Supervising Professor: Dr. Thomas Hangartner

Department of Biomedical and Human Factors Engineering Wright State University

Dayton, Ohio 45435-0001

INTRODUCTION This project was completed in conjunction with a re-gional transit authority (RTA). The purpose was to increase the accessibility of public transportation for people with visual impairments. These individuals were assumed to be free of hearing impairment, such that detection of audible signals was not a concern. An audio annunciator system was installed in a bus with a speaker located outside the bus near the door. The announcement consists of the route number and final destination of the bus. The system is activated by the opening of the door and requires little effort by the driver.

SUMMARY OF IMPACT The current RTA buses have front and side signs to display the route number and final destination of each bus. Individuals with visual impairments have a difficult time obtaining this information without as-sistance. Therefore, the implementation of an audio annunciating system was critical.

TECHNICAL DESCRIPTION The design of this system involved a microprocessor, in which the voice recordings were stored on EPROM accessed by a QuikVoice sound chip. The informa-tion is transferred to an amplifier and out through a speaker. With the product being controlled by the bus driver, the code entered for the signs accesses the nec-essary information to make the corresponding audio

announcement outside of the bus. The announce-ment is triggered when the door of the bus is opened.

The sound chip is the VP-1606, which allows mes-sages to be recorded at sampling rates from 16K to 128K pbs. Increasing the sampling frequency in-creases the amount of memory required for a given number of messages. For this project, the desired sampling rate was 32K pbs. This chip also allows di-rect access to 64 messages recorded onto the EPROM. For this prototype, only 10 messages were recorded. Thus, only a single EPROM chip was required. After the chips were programmed, the QuikVoice sound chip was connected to the external EPROM chip.

The voice chip (VP-1606) was also directly connected to the microprocessor (MC68HC11 E9). The unit was then connected to the existing hardware, specifically to the thumb-wheel/visual display used by the bus driver.

The output of the unit was then connected to the am-plifier, which was connected to the speaker. The acti-vation switch for this unit is an internally connected relay, also connected directly to the dome light volt-age wire. When the front door opens, the voltage goes high, closing the relay and activating the system.

The total cost of this system was $660.

275

CHAPTER 21 INDEX

555, 174, 175, 265, 270 555 Timer, 174, 175, 265, 270

A Adjustable Table, 52 Alarm, 122, 123, 124 Amplifier, 82, 124, 127, 130, 136, 138, 274 Ankle, 158 Antenna, 124 Armrests, 164, 189, 213, 214 Arthritis, 154, 162, 272 Asthma, 168 Audio, 73, 84, 180, 274 AutoCad, 5, 7 AutoCAD, 5, 7

B Backpack, 38, 118 Battery, 108, 109, 136, 137, 168, 174, 180, 238 Bed, 39, 50, 86, 87, 97, 124, 216, 232, 254 Bicycle, 32, 118, 119, 146, 198, 207, 224, 225, 238, 242,

244 Blind, 1, 6, 122, 177 Board, 1, 2, 7, 13, 17, 19, 42, 45, 48, 80, 82, 113, 114,

116, 122, 123, 124, 127, 136, 137, 138, 139, 194, 200, 202, 204

Book, 146 Brace, 30, 104, 150, 158, 170, 178, 242 Button, 29, 36, 64, 78, 79, 80, 92, 98, 113, 122, 177, 181,

184, 214, 227, 263, 266, 267

C CAD, 7 Camera, 126 Car, 43, 65, 80, 84, 85, 86, 148, 160, 234 Cart, 40, 118, 119, 198, 238 Cause-Effect, 2, 78

Cerebral Palsy, 28, 51, 55, 64, 66, 86, 106, 188, 190, 191, 194, 202, 234, 252, 256, 266

Chair, 28, 29, 41, 43, 44, 55, 58, 66, 72, 73, 88, 89, 108, 109, 144, 164, 177, 188, 189, 190, 191, 195, 202, 230, 248, 258, 268, 269

Chassis, 5 Child, 36, 48, 56, 60, 70, 78, 82, 83, 84, 85, 118, 180,

184, 198, 200, 234, 238, 262, 268, 269 Children, x, 1, 36, 37, 41, 43, 44, 46, 47, 48, 49, 51, 56,

60, 61, 70, 74, 78, 82, 84, 86, 116, 118, 130, 156, 184, 198, 230, 238, 262, 268, 269

Clutch, 210, 211, 212, 213, 214, 215 Communication, x, 8, 9, 13, 132, 180, 194, 206, 248,

252, 253, 256, 266 Comparator, 270 Computer, vii, 4, 5, 8, 14, 37, 84, 86, 111, 112, 113, 114,

128, 139, 166, 197, 198, 200, 202, 204, 206, 240, 248, 252, 256, 261

Control, 14, 24, 30, 45, 50, 64, 72, 73, 78, 79, 83, 84, 85, 86, 88, 92, 97, 98, 100, 108, 109, 112, 113, 114, 118, 127, 130, 136, 138, 150, 154, 156, 158, 174, 175, 176, 177, 182, 192, 216, 218, 224, 225, 226, 227, 234, 236, 238, 244, 252, 259, 263, 266, 268, 270

Controller, 83, 226, 227, 236, 240, 259 Converters, 127, 138

D Database, 3, 8, 9 Decoder, 113, 137 Desk, 37, 53 Diode, 78, 126, 138, 174 DOS, 129 Driving, 137, 162, 270

E EPROM, 274


F Feed, 86 Feedback, 3, 6, 7, 70, 84, 85, 130, 132, 136, 180, 192,

226, 270, 271, 272 Feeder, 86, 87 Fiberglass, 61, 66, 68, 142, 148 Foot, 32, 42, 55, 58, 128, 130, 158, 190, 202, 210, 211,

214, 215, 223, 230, 253, 258

G Garage Door Opener, 177 Garbage, 156 Garden, 220 Gardening, 152 Gasoline, 162 Gear, 32, 58, 192, 210, 211, 214, 215, 230, 234, 258,

259, 268 Glove, 150, 162

H Hand Brake, 65 Head Injury, 78 Head Rest, 44, 194 Head Switch, 45 Horseback Riding, 232 Hydraulic, 116, 117, 192, 211, 232, 236, 253

I Incentive, 15 Infrared, 1, 72, 174, 194, 204, 206 Intercom, 138 Inverter, 175, 176, 265

K Keyboard, 200, 256, 262, 263 Knee, 188, 190

L Laser, 1 Laundry, 182 LCD, 82, 83 LED, 13, 72, 78, 79, 122, 124, 130, 137, 168, 230, 265,

266, 270 Leg, 32, 116, 158, 189, 190, 198, 210, 238, 242, 269

M Magnet, 177 Microcontroller, 113, 126 Microphone, 113, 122, 133, 136, 137, 138, 139, 270 Microprocessor, 3, 7, 82, 83, 112, 136, 266, 267, 270,

274 Modulation, 124, 126, 138, 139 Motor, 32, 58, 78, 80, 94, 98, 106, 124, 150, 160, 177,

180, 184, 192, 200, 211, 226, 227, 230, 234, 236, 238, 240, 242, 252, 258, 259, 272

Mounting System, 195

N NSF, ix, x, 1, 2, 3, 5, 10

O Orthosis, 10, 24, 30, 31 Oscillator, 82, 124, 174

P Photography, 6 Physical Therapy, 65 Plexiglas, 68, 86, 98, 123, 124, 154, 272 Plywood, 32, 37, 39, 45, 47, 49, 52, 55, 58, 61, 74, 128,

129, 148, 184, 259, 262, 268, 269 Polyethylene, 194, 219 Potentiometers, 130 Power Supply, 7, 37, 79, 124, 139, 177, 262, 270 Pressure Relief, 108 Pronation, 192 Prosthesis, 22, 23, 24, 130 Puff Switch, 174 Pulley, 195, 210, 211, 218, 219 PVC, 36, 39, 40, 46, 48, 49, 50, 52, 55, 56, 58, 65, 66, 68,

69, 73, 80, 88, 89, 116, 202, 204, 217

R Radio, 72, 113, 122, 124 Radio Shack, 122 RAM, 136, 139 Reading, 82 Receiver, 1, 64, 112, 113, 114, 124, 138, 139, 174, 175,

176, 177, 266 Recreation, 65, 74, 92, 98, 118 Rehabilitation, vii, 2, 5, 6, 42, 52, 78, 108, 109, 112,

113, 114, 128, 158, 192, 247, 248, 252, 254, 256, 258 Relay, 64, 108, 109, 175, 176, 177, 234, 263, 274

Chapter 21: Index 277

Remote, 14, 72, 73, 97, 100, 104, 113, 114, 174, 176, 177, 180, 234, 248, 266

Remote Control, 72, 73, 97, 100, 113, 174, 176, 177, 234 RF, 113, 114 ROM, 6, 14, 32, 85, 86, 132, 139

S Saddle, 232 Safety Factor, 108, 118, 188, 191, 248 Scanner, 7 Scanning, 180 Scooter Board, 48 Screwdriver, 164 Sensor, 126, 127, 130, 194, 204 Sensory Stimulation, 78, 80, 230 Shampoo, 154 Shower, 28, 29, 154, 188, 189, 190, 191, 226, 227 Showerhead, 154, 227 Ski, 28, 32, 188, 190 Ski Boot, 32 Soap, 154 Speech, vii, x, 1, 8, 9, 18, 113, 114, 116, 122, 132, 133,

136, 138, 180, 270, 271 Springs, 126, 158, 193, 262 Standing, 42, 52, 104, 129, 200, 232, 252 Steering, 56, 65, 160, 224, 234, 236, 242, 244, 253 Supination, 192 Support, x, 1, 6, 8, 9, 14, 29, 30, 32, 40, 41, 43, 44, 48,

54, 56, 60, 66, 69, 106, 107, 108, 116, 118, 144, 152, 153, 158, 162, 178, 189, 191, 192, 194, 200, 202, 204, 207, 210, 211, 213, 214, 215, 216, 217, 220, 221, 223, 230, 234, 236, 238, 242, 244, 248, 252, 253, 256, 258, 259

Swing, 74, 118, 180, 189, 204, 230 Switch, 45, 47, 73, 79, 97, 98, 100, 108, 109, 122, 124,

129, 156, 174, 176, 177, 180, 181, 195, 200, 230, 262, 263, 265, 266, 267, 270, 271, 274

T Table, 37, 46, 52, 86, 98, 116, 117, 129, 170, 200, 202,

248, 269 Telephone, 1, 8, 177 Texas Instruments, 136, 138, 139 Thermocouple, 226, 227 Timer, 82, 83, 85, 108, 109, 127, 128, 156, 174, 175,

176, 265 Toilet, 190 Toy, 49, 78, 80, 82, 83, 184, 234, 262 Toys, 36, 49, 113, 184 Train, 84 Trainer, 262, 263 Training Wheels, 198 Transmission, 112, 138 Transmitter, 64, 112, 113, 114, 124, 138, 139, 174, 176 Transportation, 104, 274 Tricycle, 61, 224, 225, 242, 244 Tub, 226, 227

U Utensil, 86, 170

V Velcro, 31, 32, 45, 64, 86, 108, 152, 153, 154, 158, 204,

207, 217 Visual Impairment, 37, 122, 126, 274 Voice, x Voice Synthesizer, 204

W Walker, 37, 56, 106, 158 Wheel, 28, 54, 55, 56, 65, 89, 98, 106, 118, 160, 219,

224, 225, 234, 236, 242, 244, 269, 274 Wheelchair, 10, 28, 37, 50, 53, 54, 55, 64, 74, 84, 86, 88,

104, 105, 108, 114, 144, 146, 148, 164, 166, 182, 191, 204, 206, 210, 224, 225, 232, 236, 248, 252, 266, 268

Work Station, 53