An Evaluation of BrailleTouch : Mobile Touchscreen Text Entry for the Visually Impaired

We present the evaluation of BrailleTouch, an accessible keyboard for blind users on touchscreen smartphones. Based on the standard Perkins Brailler, BrailleTouch implements a six-key chorded braille soft keyboard. Eleven blind participants typed for 165 twenty-minute sessions on three mobile devices: 1) BrailleTouch on a smartphone; 2) a soft braille keyboard on a touchscreen tablet; and 3) a commercial braille keyboard with physical keys. Expert blind users averaged 23.2 words per minute (wpm) on the BrailleTouch smartphone. The fastest participant, a touchscreen novice, achieved 32.1 wpm during his first session. Overall, participants were able to transfer their existing braille typing skills to a touchscreen device within an hour of practice. We report the speed for braille text entry on three mobile devices, an in depth error analysis, and the lessons learned for the design and evaluation of accessible and eyes-free soft keyboards.QC 20160418