CHRONOS-CONTROL COMPUTER CONTROL USING TI CHRONOS Cihat Keser Yeditepe University

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

Data Layer Manages connection between Chronos and computer Polls Chronos For acceleration data Keeps a collection of previously received data Logic 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

 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)

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

Evaluation Results (Mouse)  Test subjects clicked on eight circles randomly drawn on screen, three times  Changed maximum mouse speed and repeated

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!