p13071: non-invasive blood glucose monitor -...

P13071: Non-Invasive Blood

Glucose Monitor System Level Design Review

Jared Bold, Yongjie Cao, John Louma, Andrew Rosen, Daniel Sinkiewcz

S21 Antenna

Cable to LabVIEW

Device Under Test (DUT)

KGCOE MSD Technical Review Agenda

KGCOE MSD Page 1 of 2 Technical Review Agenda

P13071: Non-Invasive Blood Glucose Monitor

Meeting Purpose:

1. Overview of project 2. Confirm Customer needs and Specifications 3. Review variety of concepts designs 4. Propose our selected design 5. Generate new ideas

Materials to be Reviewed:

1. Project Description and Objective 2. Work Breakdown Structure 3. Customer Needs 4. Customer Specifications 5. Functional Decomposition 6. Concept selection process 7. Risk Assessment 8. Project Plan

Meeting Date: April 5, 2013

Meeting Location: Room 09-4435

Meeting time: 10:00 – 11:30 AM

Timeline:

Meeting Timeline

Start time

Topic of Review Required Attendees

10:00 Introduction for the Project Prof. Slack, Dr. Venkataraman

10:10 Work Breakdown Structure Prof. Slack, Dr. Venkataraman

10:15 Customer Needs Prof. Slack, Dr. Venkataraman

10:25 Customer Specifications Prof. Slack, Dr. Venkataraman

10:35 Functional Decomposition and Block Level Diagrams Prof. Slack, Dr. Venkataraman

10:55 Concept Development and Chosen Design Prof. Slack, Dr. Venkataraman

11:10 Risk Assessment Prof. Slack, Dr. Venkataraman

11:20 Project Plan Prof. Slack, Dr. Venkataraman

KGCOE MSD Page 2 of 2 Technical Review Agenda

Project Description . Project Background: Blood glucose monitoring is a valuable tool not only used by diabetic individuals to maintain a healthy lifestyle, but also by physicians caring for patients. Today's accurate monitoring systems are invasive, requiring direct access to a patient's blood for accurate analysis. The blood glucose meter pricks the finger in order to obtain a drop of blood from which a discrete glucose level can be determined. Continuous glucose measurements can be obtained by placing a glucose sensor subcutaneously, which delivers measurements to an external system. There is a distinct lack of noninvasive glucose monitoring alternatives that can provide the same level of accuracy.

Problem Statement:

Develop a non-invasive real time monitoring system that measures blood glucose. The system should use a microstrip antenna to measure reflection and transmission of a synthesized signal. These measurements should be comparable to a network analyzer.

Objectives/Scope:

Improve accuracy of current noninvasive glucose monitoring system

Provide a method of real time monitoring of patient's blood glucose levels

Archive measurement data for future analysis

Obtain a transmission signal and perform a vector measurement

Deliverables:

Improved accuracy of reflection vector measurements

Compact printed circuit board layout

Introduce calibration system to further increase accuracy measurements

Visual representation of data through LabVIEW graphical user interface

Expected Project Benefits:

Current blood glucose monitors are invasive and discourage multiple measurements. There are many benefits to having a well designed non-invasive blood glucose monitor. It will allow patients to continuously monitor their blood glucose and will encourage the patients to monitor their levels more often. The system will also allow for data archival, so a history of blood glucose levels can be analyzed.

Core Team Members:

Jared Bold

Yongjie Cao

John Louma

Andrew Rosen - Project Manager

Dan Sinkiewicz

Strategy & Approach .

Assumptions & Constraints:

The team will use a two antenna system to measure both the transmission and reflection coefficients of the user's limb. The system must be designed to minimize undesired effects on the antenna system, such as coupling. A calibration system for the measurement circuit will be designed to improve measurement accuracy. The data must be processed and displayed through LabVIEW and compared real time to automated Network Analyzer measurements to verify accuracy.

Issues & Risks

Difficulty measuring transmission through arm

The antennas might couple or the "creeping wave" effect could alter measurements

Peripheral devices could be difficult to integrate successfully

Patient could be at risk of slight shocks if the system short circuits

Summary of Ben Freer’s Thesis

The present work on blood glucose monitors focuses on the possibility of a monitor that

non-invasively measures blood glucose levels using electromagnetic waves. The technique is

based on relating a monitoring antenna’s resonant frequency to the permittivity and conductivity

of blood which in turn is related to the glucose levels.

Using the Agilent 85070E dielectric probe and an Agilent 8720B network analyzer, the

dielectric permittivity and conductivity of twenty different blood samples was measured over a

frequency range of 1GHz – 10GHz. The Cole-Cole model was modified through curve fitting to

in-vitro data that includes a factor representing glucose level. The desired frequency sweep range

for the monitor was then determined to be 200MHz to 2GHz.

An antenna was been designed, constructed and tested in free space. A simulation model

of layered tissue and blood together with an antenna was created to study the effect of changing

glucose levels. It is noted that the antenna’s resonant frequency increases with increase in

glucose levels. An analytical model for the antenna was developed, which was validated with

simulations. A measurement system was developed to measure the resonant frequency of the

antenna. A frequency synthesizer generates an RF signal over the desired frequency range of

200MHz to 2GHz. This signal is sent to the antenna through a directional coupler that generates

forward and reflected signals. These voltages are measured and the reflection coefficient is

calculated with a microprocessor.

As an experimental verification, two antennas were strapped one on each leg of a patient

with one antenna connected to the PNA and the other to the measurement system. As the patient

ingested fast acting glucose tablets, the blood glucose level was measured by a traditional

glucose meter. At the same time, a comparison of the resonant frequency of the antenna

measured by the PNA and by the measurement system showed good agreement. Further, it is

seen that the antenna resonant frequency increases as the glucose level increases, which is

consistent with the simulation model.

Non-Invasive Blood Glucose Monitor

Data Collection Calibration

Power SystemRegulation

Data Measurement

Data Analysis

Power Source

Voltage Regulation

Battery Pack

3.3/5V

Short Protection

Measure open, short, load, through

Low Power Mode/Indication

Transfer/store reference points

TX RF Signal (PLL)

RX RF Signal (S11) (REFLECTION)

Transmit Phase and Magnitude change to

μController

Filter RF Signal

Scale Signal

Filter RX Signal

Store

Transmit to computer

Labview GUI

USB

Calculate resonant over time

Plot Data

Archive Data

Calibration command

RX RF Signal (S21) (TRANSMISSION)

Filter RX Signal

Determine Change in Phase and Magnitude

Determine Change in Phase and Magnitude

ADC

Andrew Rosen-Project Manager

Power Unit

Computer

Measurement System

Microcontroller

John Louma (backup)

Jared Bold

Dan sinkiewicz

Yongjie Cao

PCB Layout

RF Transmission S21

Andrew Rosen (backup)

Jared Bold (backup)

RF Path

Antenna

Vector Measurement

Andrew Rosen

John Louma

John Louma(backup)

Dan Sinkiewicz

Andrew Rosen(backup)

John Louma(backup)

RF Transmission S11

John Louma

Yongjie Cao

John Louma(backup)

Yongjie Cao(backup)

Revision #:

Customer

Need #Importance Description Comments/Status

Measurement System

CN1 5 More accurate resonant frequency measurement Explore other options

CN2 5 Perform frequency sweep Other synthesizers?

CN3 5 Calibration System Short, open, load

CN4 3 Incorporate dual antenna system Measure transmitted and reflected signals

CN5 5 Verify antenna performance in real time Labview and network analyzer

CN6 4 Resolution (time) Sample rate

Microprocessor Data Handling

CN7 5 Communication with PC Wired VS. wireless

CN8 5 Controlling frequency sweep

CN9 3 Resolution (bit size)

PC Data Analysis

CN10 4 Parse data Labview

CN11 5 Real time update Labview

CN12 5 Display data Labview

CN13 2 Archive data

Physical Attributes

CN14 5 Compact PCB

CN15 5 Non-invasive

Functionality

CN16 4 Battery power Portable

CN17 2 Low power notification

CN18 3 Ergonomic fit on a limb Arm or leg?

CN19 4 Power conservation Low power when not used

Cust. Need #: enables cross-referencing (traceability) with specifications

Importance: Sample scale (1=must have, 2=nice to have, 3=preference only), or see Ulrich exhibit 4-8.

Description: organize as primary and secondary needs (hierarchy) -- Ulrich exhibit 4.8

Comment/Status: allows tracking of questions, proposed changes, etc; indicate if you are meeting the need ("met") or not ("not met")

Spec. # Importance Source Function Specification (metric)Unit of

Measure

Marginal

ValueIdeal Value

Comment

s/Status

Measurement System

S1 5 CN1 Antenna Performance Accuracy of measurement system compared to Network Analyzer KHz 15 10

S2 5 CN4 Power absorbtion Power of transmitted signal mW 200 150

S3 4 CN2 Frequency Sweep Check for resonant frequency between 200 MHz and 4 GHz MHz 200-4000 200-2000

S4 5 CN3 Calibration Time required for calibration Seconds 60 1

S5 4 CN4 Resonant Frequency Determination Bandwidth of Narrowband Antenna MHz 15 10

S6 5 CN4 Resonant Frequency Determination Bandwidth of Wideband Antenna MHz 200-2000 100-3000

S7 4 CN4 Power absorbtion return loss of Narrowband Antenna dB -20 -15

S8 5 CN4 Power absorbtion return loss of Wideband Antenna dB -20 -15

S9 4 CN4 Phase change Max phase change degrees 180 180

S10 3 CN6 Sampling Intervals between measurements Seconds 60 15

Microprocessor Data Handling

S11 3 CN7 Data Transmission Time required for packet transmission Seconds 2ms 1us

S12 3 CN9 Analog to Digital Converter Bit resolution Bits 10 16

S13 5 CN11 Update Time Time between microprocessor transmission and data display Seconds 10ms 8ms

PC Data Analysis

S14 2 CN12 Data Display Amount of data points Data Points 20 240

S15 2 CN13 Data Storage Amount of data stored Bytes 1MB 1KB

Physical Attributes

S16 3 CN14 Printed Circuit Board Layout Size Inches 3x3 Less than 3x3

Functionality

S17 3 CN16 Power Source Battery Voltage Volts 5 3.3

S18 3 CN17 Low Power Notification Time before battery death Minutes 30 5

Spec. #: enables cross-referencing (traceability) and allows mapping to lower level specs within separate documents

Source: Customer need #, regulatory standard (eg. EN 60601), and/or "implied" (must exist but doesn't have an associated customer need), constraint

Description: quantitative, measureable, testable details

*This table can be expanded to document test results

Non-Invasive Blood Glucose Model

Incident Signal

Reset

Transmitted Signal

Resolution

P13071 Non-Invasive Blood Glucose MonitorLevel 0 Functional Block Diagram

Device Under Test (DUT)

Computer ( LabVIEW)Data to computer

Reflected Signal

Open, Short, Load, Through

USB

Battery PackPower Regulator

Hard Drive(Archive)

Plot Data

Math Manipulation

Port Choice

USB

Physical Button

P13071 Non-Invasive Blood Glucose Monitor

Level 1 Functional Block Diagram

Resolution

Arm/Sample

RF Synthesizer

Antenna (S11)

Vector Measurement

(Scattering Matrix)

Antenna (S21)

Vector Measurement

(Scattering Matrix)

Directional Coupler

Directional Coupler

RF Splitter

Inci

den

t

Inci

den

t

Tran

smit

ted

Reference

Reference

Reference

Reflected

Ref

lect

ed

MIcrocontroller

Level0 microSoftware.vsdx

POR (Power-on Reset)

Calibrate RF PathTransmit Calibration

Data to HostInitialize Synthesizer

Begin sweep command from PC?

Enter Low Power Mode

Transmit Synthesizer Signal

Measure S11Measure S21Send S Matrix to

PC / Store S Matrix in Flash

Sweep Complete?

No

No

Sweep Interval Timer Expired

Enter Low Power Mode

No

Yes

Reset

Brown Out

Stop

Microcontroller Level 0 Functional Block Diagram


Screening - GUI

Concepts

A B C D E

Matlab C++ Mobile Platform (Reference)

On board

Screen/processing

Selection Criteria LabVIEW

USB interface 0 0 - D -

Ease of programming + - - A -

Ease/ability to Interface with peripherals 0 - - T -

Familiarity + + - U -

M

Sum + 's 2 1 0 0 0

Sum 0's 2 1 0 0 0

Sum -'s 0 2 4 0 4

Net Score 2 -1 -4 0 -4

Rank 1 3 4 2 4

Continue? Yes


Screening - RF Synthesizer

Concepts

A B C D E G

VCO Crystal Reference DDS RF Mixer

Selection Criteria PLL

Frequency range - - d - -

Deviation from set frequency - + a 0 0

small footprint 0 - t 0 0

Input signal 0 + u 0 -

m

d

a

t

u

m

Sum + 's 0 2 0 0

Sum 0's 2 0 3 2

Sum -'s 2 2 1 2

Net Score -2 0 0 0 -1 -2

Rank 5 2 1 3 4

Continue? No No No Yes No No


Screening - Calibration

Concepts

A B C D

Mux with on chip loads External loads (Reference)

Selection Criteria None

Automated + 0 D

Ease of implementation - + A

Programming complexity - 0 T

Calibration - + U

Usability + - M

Space required + -

Sum + 's 3 2 0

Sum 0's 0 2 0

Sum -'s 3 2 0

Net Score 0 0 0

Rank

Continue? Yes No No


Screening - Communication Interface

Concepts

A B C D E G

USB Bluetooth Zigbee RS-232

Selection Criteria (Ben's Thesis)

Power Usage during transmission + + + d

Power Usage during idle 0 + + a

Transfer speed + + + t

Power Supply + 0 0 u

Error rate 0 - - m

Distance of communication 0 0 0

Ease of implementation 0 0 0 d

Cost to implement - - - a

Space to implement - - - t

Ease of computer interface - - - u

m

Sum + 's 3 3 3 0

Sum 0's 4 3 3 10

Sum -'s 3 4 4 0

Net Score 0 -1 -1 0

Rank 1 4 3 2

Continue? Yes No No No


Screening - Processor

Concepts

A B C D E G

MSP430 Stellaris ARM C2000 Reference Hercules ARM Arduino

Selection Criteria PIC

I2C 0 0 0 D 0 0

UART 0 0 0 A 0 0

SPI 0 0 0 T 0 0

USB 0 - 0 U - -

ADC + - - M - -

Flash Memory 0 - 0 + -

Clock Speed 0 + + + -

GPIO - - - - -

Sum + 's 1 1 1 0 2 0

Sum 0's 6 3 5 0 3 3

Sum -'s 1 4 2 0 3 5

Net Score 0 -3 -1 0 -1 -5

Rank 1 3 2 1 2 4

Continue? Yes No No No No No


Screening - On Device Storage

Concepts

A B C D E

Removable SD card uC Flash Flash mem chip (Reference) Flash drive

Selection Criteria None

Storage Size + + + D +

Storage Speed + + + A +

Ease of Access 0 0 0 T 0

Ease of Implementation - 0 - U -

Cost - 0 - M -

Sum + 's 2 2 2 0 2

Sum 0's 1 3 1 0 1

Sum -'s 2 0 2 0 2

Net Score 0 2 0 0 0

Rank 2 1 2 2 2

Continue? No Yes No No No

P13071 Non-Invasive Blood Glucose MonitorScreening - Microstrip Antenna Designs

Concepts

A B C D E

Patch Dipole vivaldi Reference Bowtie

Selection Criteria planar

inverted f

size 0 0 0 D 0

groundplane + + - A +

bandwidth + - 0 T +

ease of design + + - U -

M

D

A

T

U

M

Sum + 's 3 2 0 0 2

Sum 0's 1 1 2 0 1

Sum -'s 0 1 2 0 1

Net Score 3 1 -2 0 1

Rank 1 2 5 3 4

Continue? Yes No No No No

MSD Project Risk Assessment

ID Risk Item Effect Cause Like

liho

od

Seve

rity

Imp

ort

ance

Action to Minimize Risk Owner

1

Compensating for Electrical Delay

Calibration won’t be accurate

Calibration 2 2 10 Develop a check in code to adjust for electrical delay

Andrew

2 Transmission through arm won’t work Inability to measure S21

Arm causes too much attenuation 3 3 5

Use appropriate power in design for microwave sensors Andrew

3 Coupling between antennas

Accuracy of measurement S11, S21

Antennas are place too close together 2 3 10

Place device in area this is unlikely to occur Andrew

4 Noise being introduced in Channel

Bad measurement of S11, and S21

Movement, body type, environment 3 2 9 Designed to reduce transience Jared

5 Synthesizer lock time Lengthen/restrict resolution

Switch time on synthesizer 1 1 6 Synthesizer choice Dan

6 Peripheral configuration issues

Peripheral devices won’t perform as intended

Inappropriately set registers 2 3 10 Dev boards for all peripherals Dan

7 Dielectric gel could affect measurement Could shift resonance

Dielectric not modeled properly 1 2 8 Research dielectric gel Andrew

8 Patient electrocution Could harm patient Short power to device 1 2 10 Power isolation Yongjie

9 Program hangup Loss of functionality Poor programming 1 3 10 Spend time reviewing code John

10 Not accurate reference signal

S11 and S21 will not be correct

RF splitter doesn’t work 1 3 10 Validate power splitter Andrew

12 PCB layout Not knowing how to do an RF pcb

13 Directional coupler Not working at right freq

Likelihood scale Severity scale

1 - This cause is unlikely to happen 1 - The impact on the project is very minor. We will still meet deliverables on time and within budget, but it will cause extra work

2 - This cause could conceivably happen 2 - The impact on the project is noticeable. We will deliver reduced functionality, go over budget, or fail to meet some of our Engineering Specifications.

3 - This cause is very likely to happen 3 - The impact on the project is severe. We will not be able to deliver, or what we deliver will not meet the customer's needs.

“Importance Score” (Likelihood x Severity) – use this to guide your preference for a risk management strategy

Prevent Action will be taken to prevent the cause(s) from occurring in the first place.

Reduce Action will be taken to reduce the likelihood of the cause and/or the severity of the effect on the project, should the cause occur

Transfer Action will be taken to transfer the risk to something else. Insurance is an example of this. You purchase an insurance policy that contractually binds an insurance company to pay for your loss in the event of accident. This transfers the financial consequences of the accident to someone else. Your car is still a wreck, of course.

Accept Low importance risks may not justify any action at all. If they happen, you simply accept the consequences.

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