Single-handed smartwatch text entry with WrisText

Smartwatches can keep us informed of incoming information at a glance, but responding still takes the use of another hand, potentially occupied by other tasks. Researchers at Dartmouth College are trying to change that with their new WrisText system.

The device divides the outside of a Ticwatch 2 into six sections of letters, selected by the movement of one’s wrist. As letters are chosen, possible words are displayed on the screen, which are then selected automatically, or by rubbing and tapping gestures between one’s finger and thumb. 

The prototype employs an Arduino DUE to pass information to a computer, along with proximity and piezo sensors to detect hand and finger movements. 

We present WrisText – a one-handed text entry technique for smartwatches using the joystick-like motion of the wrist. A user enters text by whirling the wrist of the watch hand, towards six directions which each represent a key in a circular keyboard, and where the letters are distributed in an alphabetical order. The design of WrisText was an iterative process, where we first conducted a study to investigate optimal key size, and found that keys needed to be 55o or wider to achieve over 90% striking accuracy. We then computed an optimal keyboard layout, considering a joint optimization problem of striking accuracy, striking comfort, word disambiguation. We evaluated the performance of WrisText through a five-day study with 10 participants in two text entry scenarios: hand-up and hand- down. On average, participants achieved a text entry speed of 9.9 WPM across all sessions, and were able to type as fast as 15.2 WPM by the end of the last day.

More information can be found in the project’s research paper, or you can see it demonstrated in the video below.