Innovative Control System for Users with Disabilities via Head Motion Input

1. Chronos-controlcomputer control using tI chronos Cihat Keser Yeditepe University - 2011

2. Presentation Plan • Introduction & Problem Definition • Proposed Solution Concept • Overall Software Design • System Calibration • Mouse Control • Keyboard Control • Evaluation Results

3. Introduction & Problem Definition 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

4. 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)

5. 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

6. Proposed Solution Concept Section 2 of 7

7. 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

8. 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

9. Overall Software Design Section 3 of 7

10. Overall Software Design

11. System Calibration Section 4 of 7

12. 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

13. Mouse Control Section 5 of 7

14. 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

15. 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

16. 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

17. Keyboard Control Section 6 of 7

18. 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

19. 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

20. Evaluation Results Section 7 of 7

21. 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

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

23. 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

24. Thank You!