WristWhirl: One-handed Continuous Smartwatch Input using Wrist Gestures

Motivation

Interacting with current smartwatches often necessitates both hands for scrolling or gesturing. However, in many situations, two handed interactions may interrupt our current text. For example, when a user is riding a bike, he has to stop the bike to interact with the watch. There are also some similar situations when the other hand is occupied by daily activities, such as grabbing a handle on a bus, holding an umbrella in a rainy day, etc. Therefore, one-handed interaction with smartwatches can help our users to free one hand, which may be a good alternative in many situations.

Prototype

This is our proof-of-concept prototype. We augmented 12 infrared proximity sensors along the watch strap. Each is composed of a pair of IR emitter and detectors. The proximity sensor operates at 940nm, distinguished its signal from visible light. We also attached a piezo vibration sensor inside the watch strap. Sensor can detect sound of the finger pinch propagating through the user’s skin so that user can use pinch to indicate start or end of the gesture.

Applications

We built four applications to demonstrate the possibilites of WristWhirl.

• The first application is a gesture shortcut app. User can draw a triangle to open a calendar app or draw a "L" to quick dial a number to a friend called Lisa.
• The second application is a music player app. Users can use wrist extension/flexion to scroll a list of songs. With WristWhirl, a long wrist-swipe allows the user to quickly skip a number of songs whereas a short wrist-swipe advances one song at a time.
• The third application is a 2D navigation app. User can pan a map using the same hand wearing the watch. User can also rotate his wrist to zoom in/out.
• The four application is for the game input. User can play Tetris game and Fruit Ninja using the WristWhirl.

For more details, please check the application section in our video.

Selected Press Coverage

Wall Street Journal: A Smartwatch That Works With One Hand

TechCrunch: WristWhirl lets you control your smartwatch with hand gestures

Discovery's Daily Planet: FLICK OF THE WRIST

Gizmodo: Smartwatch Prototype To Use Wrist As Joystick

Phys.Org: Dartmouth-led team develops WristWhirl, a smartwatch prototype using wrist as a joystick