Operating a smartwatch, in most cases, requires the use of both hands and can become tedious if one hand is holding an object or occupied with tasks. Researchers from Dartmouth College and the University of Manitoba are looking to address this problem using WristWhirl.

According to the researchers, while there are efforts to develop methods that allow sameside hand (SSH) operation of smartwatches, they are centered on discrete input operations and on commands through finger postures. And while tilting the wrist may be a viable approach, losing sight of the smartwatch's display becomes the consequence.

The WristWhirl Project

The WristWhirl project explores an alternative approach using whirls and continuous wrist movements to operate smartwatches using the same hand.

"When observing the collective range-of-motions of the wrist along each of its axes of movement, the hand can be viewed as a natural joystick," Jun Gong, Xing-Dong Yang and Pourang Irani detail in their paper titled WristWhirl: One-handed Continuous Smartwatch Input using Wrist Gestures. "We explore the ability of the human wrist to perform complex gestures using full wrist motions, or wrist whirls."

WristWhirl Prototype

As a proof-of-concept, the team of three designed and built the WristWhirl prototype, which has a 2-inch TFT display. They augmented the watch strap with a dozen infrared proximity sensors and a Piezo vibration sensor that are connected to an Ardruino DUE microcontroller board. The board then gets hooked to a laptop that reads the sensor data.

Gestures

Once the device is strapped to a wrist, the user has to perform a pinch to mark the start of a gesture. Another pinch is needed to tell the system that the gesture ended. In total, the team studied 8 gestures with four for directional — up, down, left, right — and the other half for free-form: circle, rectangle, and question mark.

Note that respondents only took half a second to perform that directional gestures while it took them a second and a half for a free-form gesture.

To illustrate the potential usage scenarios for the said gestures, the team designed four applications - gesture shortcuts, music player, 2D navigation and game input.

Directional gestures, such as swiping, can be used for navigating content within apps - a music player for instance. They can also be good for map navigation - using swipe to pan a map and double taps for zooming. These gestures are the equivalent of flicking a touch screen.

On the other hand, free-form gestures, which allow for more complex shapes, can be used to launch preassigned apps or to call a number on speed dial. In combination with directional gestures, games such as Tetris and Fruit Ninja can be played.

The paper will be presented next week at the 29th annual ACM Symposium on User Interface Software and Technology, which will be held in Tokyo, Japan. Below is a video demonstrating how the WristWhirl prototype works.