CHRONOS-CONTROLCOMPUTER CONTROL USİNG TI

CHRONOS

Cihat Keser

Yeditepe University - 2011

Presentation Plan

Introduction & Problem Definition Proposed Solution Concept Overall Software Design System Calibration Mouse Control Keyboard Control Evaluation Results

Section 1 of 7

«For me being online is everything. It’s my hi-fi, my source of income, my supermarket, my telephone. It’s my way in.» Lynn Holdsworth, screen reader user, Web Developer and Programmer

Introduction & Problem Definition

Introduction & Problem Definition (1)

Computers are already part of our daily life

All modern services are being

«computerized»

Human computer interface alternatives are

limited

Some people cannot use traditional

interfaces (mouse and keyboard)

Introduction & Problem Definition (2)

This project aims to provide an

alternative interface

Target user base is disabled people who

can still move (tilt) their head

Section 2 of 7

Proposed Solution Concept

Proposed Solution Concept (1)

Head acceleration data acquired using wireless head mounted accelerometer

TI Chronos is wireless and includes an accelerometer

Data analyzed by Java application and translated to keyboard or mouse input

Proposed Solution Concept (2)

Acceleration data converted to pitch & roll degrees

Not possible to calculate yaw using single accelerometer

Analysis works on pitch & roll degrees

Section 3 of 7

Overall Software Design

Overall Software Design

Data Layer• Manages connection between Chronos

and computer• Polls Chronos For acceleration data• Keeps a collection of previously received

dataLogic Layer• Chooses the appropriate analyse logic

depending on operation mode (keyboard, mouse or calibration)

• Passes any detected input events (output of analyzer) to the Operating System (OS)

User Interface Layer• Manages and updates the user

interface

Section 4 of 7

System Calibration

System Calibration

Analyzer needs to know the limits of the user

Calibration carried out by a wizard like

interface

Four steps are involved:

Neutral area detection

Usable area detection

Left click characteristics detection

Right click characteristics detection

Section 5 of 7

Mouse Control

Mouse Control (1)

Tilting head in any direction moves the

cursor

Simple speed adaptable relative mapping

used

New cursor location calculated relative to

old location

Cursor speed directly proportional to tilt

degree

Mouse Control (2)

Clicking only possible in «click mode»

Cursor movement disabled in click mode

Staying in neutral position enables click mode

Making a click movement, simulates mouse click

A successful click or timeout disables click mode

Mode switcher interface shows click mode status

Mouse Control (3)

Click movement detection done by analyzing past data collection

Peak and two closest neutral points found

Height and duration calculated

Compared to characteristic values obtained in calibration

Tilt angle versus time plots for (a) left (b) right clicks

Section 6 of 7

Keyboard Control

Keyboard Control (1)

Clicking the button on «mode switcher» while in mouse mode, switches

operation mode to keyboard

An on screen keyboard (OSK) is shown

OSK has special layout to compensate for head’s circular motion limitation

Keyboard Control (2)

Tilting head changes the selected key

Key navigation uses absolute mapping method

Usable tilt range divided to number of keys

Waiting on a key, simulates a key press event

To avoid navigation jitter, key stickiness parameter

proposed

Selected key changes only if multiple contionous data is

received to select it

Section 7 of 7

Evaluation Results

Evaluation Results (Keyboard) Test subjects typed

«the quick brown fox jumps over the lazy dog» three times

Changed waiting time to press a key (W) and repeated

Changed stickiness and repeated W = 700ms W = 800ms

210

231

240

216

Average time spent typing (seconds)

Stickiness ONStickiness OFF

Evaluation Results (Mouse)

Test subjects clicked on eight circles randomly drawn on screen, three times

Changed maximum mouse speed and repeated Average of all subjects

149156

178

Average time spent to click all circles (seconds)

Vmax=10pixelsVmax=14pixelsVmax=18pixels

Evaluation Results

Test subjects had difficulty using click mode

Simple speed adaption method for cursor

movement was partially effective

Special keyboard layout successfully solved

circuilar motion limitation problem

Keyboard jitter was not solved by stickiness

parameter

Thank You!