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.
Text entry is a common and important task in daily mobile life, comprising of approximately 40% of mobile activity. However, entering text on a smartwatch is challenging because of the small form factor and its wearable context. One of the most commonly observed problems is the need to use one or both hands for a task (e.g. driving or walking while holding an umbrella or shopping bags). This is cumbersome in the context of smartwatches, as a user is required to interrupt their ongoing task to enter text, which reduces the purposefulness of smartwatches, as they are predominantly valuable for accessing information while on-the-go.
How WrisText Works
WrisText is a one-handed text entry technique for smartwatches using the wrist’s joystick-like motion. With it, a user whirls the wrist of the same-side hand to strike directional marks to select keys on a circular keyboard on a smartwatch. To enter “you”, a user selects [YZAB] -> [ONML] -> [TUVWX] by striking the wrist N -> S -> W. The entered text and suggested auto-complete are shown on the screen.
|Enter “Y”||Enter “O”||Enter “U”||Select “YOU”|
Our hardware is similar to the one presented in WristWhirl. The device contains a Ticwatch 2 and a plastic watch strap augmented with 12 infrared proximity sensors (LITON LTE-301 & 302) placed approximately 0.4 cm apart from each other. We connected the sensors to an Arduino DUE microcontroller, which is connected to a laptop reading sensor data at a speed of 9600 Hz. Data is then sent and visualized on the Ticwatch 2 through Bluetooth. Pinch and rub is detected using piezo vibration sensors placed inside the wrist strap.
Selected Press Coverage
Weather Science: Smartwatch Enters Text with Wrist Movements
Discovery’s Daily Planet: Replies from the wrist