200 likes | 353 Views
Human Computer Interaction Institute School of Computer Science Carnegie Mellon University. Text Input to Handheld Devices for People with Physical Disabilities. Brad A. Myers and Jacob O. Wobbrock Human Computer Interaction Institute School of Computer Science Carnegie Mellon University
E N D
Human Computer Interaction Institute School of Computer Science Carnegie Mellon University Text Input to Handheld Devices for People with Physical Disabilities Brad A. Myers and Jacob O. Wobbrock Human Computer Interaction Institute School of Computer Science Carnegie Mellon University Pittsburgh, PA 15213-3891 bam@cs.cmu.eduhttp://www.pebbles.hcii.cmu.edu/assistive/
Motivation • Provide text entry for people with physical disabilities • For handheld devices like Palm Pilots • Also called Personal Digital Assistants (PDAs) • Also use Palm Pilots as interface to desktop computers
Part of the Pebbles Project • Investigate use of handheld devices like Palm Pilots and PocketPCs, and Smartphones at the same time as PCs and other devices P E B B L E S DAs for ntry of oth ytes and ocations from xternal ources. http://www.pebbles.hcii.cmu.edu/
First Steps • Support people with Muscular Dystrophy • Low strength, limited motion, but high accuracy • Tiny keyboard on handheld screens are good
Use Our Remote Commander • Palm Pilot application to control PC using the Palm • Extend tiny keyboard with other keys • Word completion • Other adaptations: no auto-repeat, no auto-off • Mouse control on same screen • Wireless or wired
But what about other disabilities? • Cerebral Palsy, Parkinson’s, Spinal Injury, and many others • Loose accuracy as well as strength • Tiny buttons are exactly wrong • Still can’t do Graffiti, etc.
New Design: EdgeWrite™ • Added custom template with a square hole to input area • Gain stability from edges • Travel along edges and into corners • Designed alphabet usinggestures inside of hole,along edges and intocorners
Alphabet Properties • Recognizes based on sequence of corners • Users can wiggle during diagonals • Not speed dependent • Easy to customize and adapt letter forms • Even user-driven • Letters “feel” normal • Use multiple strokes along edge • Presentation (only) uses arcs • No capitalization mode • Capitals end in upper left • No special mode for numbers • I on left, 1 on right
Actual Alphabet from User Studies • Wanted high guessability • Correlates with initial usability • Designed a technique to let users guess the gestures • Told users the rules • Then resolve conflicts if same shape used twice • Left multiple forms for each letter • Result: guessability improved from 51% to 80%
EdgeWrite on Palm • Novice able-bodied users • Same speed with Graffiti and EdgeWrite • But EdgeWrite 18% more accurate • Handicapped users • Too few for statistical significance, but dramatic • E.g., accuracy: 31% with Graffiti vs. 94% EdgeWrite • For example: • “The dog is going fast” vs:“The g i gbsiangu% fast”
EdgeWrite on Game Controllers • Some joysticks use a square hole • Current techniques are veryawkward: • On-screen keyboard • “Date-stamp” cycling letters at each spot
EdgeWrite on Wheelchair • Look at people who use powerwheelchairs • Custom hardware and softwareto interface to commercial joystick • Informally evaluated with 7 disabled power-wheelchair users • 6 with Cerebral Palsy, 1 with Multiple Sclerosis
Touchpad EdgeWrite • Adaptation that uses elevated edges around a Synaptics touchpad • May be easier for people with motor impairments
Results • Touchpad worked better than wheelchair joystick • Still pretty slow
EdgeWrite on 4 Buttons • Only need four corners • Implementation for any 4 keys • Four keys on the Logitech steering wheel • Not necessarily for text entry while driving • Text entry especially for navigation system
EdgeWrite with Trackball & Pointing Stick • Newest version • Many disabled users prefer trackballfor desktop pointing • EdgeWrite for desktop • Optimized for trackball and pointing stick • Also works with regular mouse • Highly parameterized • Input window can be transparent when in use • Has help, etc. • Up to 20 wpm
Initial Reaction to Trackball Version • One user in long-term trial • Spinal injury, quadriplegic, with some mobility of one arm • Given up on-screen keyboard in favor of EdgeWrite • Still uses speech entry when possible • With practice, EdgeWrite is faster “With an on-screen keyboard, there is just too much visual scanning and concentration. In EdgeWrite, if you know the letter, you just bang it out by feel, and you can keep your eyes on your document.”
Summary and Future Work • EdgeWrite works across a wide range of devices • With the same alphabet • Learn once • Use most comfortable device • Future work • Continue to refine • Add word completion • Further tests and deployment • New devices (phone?)
Acknowledgements • Funded by grants from NSF, General Motors and The NEC Foundation of America • Equipment grants from: • Synaptics, Inc. • A.T. Sciences • Microsoft http://www.edgewrite.com/ http://www.pebbles.hcii.cmu.edu/