Seesaw: rapid one-handed synchronous gesture interface for smartwatches.

We present SeeSaw, a synchronous gesture interface for commodity smartwatches to support watch-hand only input with no additional hardware. Our algorithm, which uses correlation to determine whether the user is rotating their wrist in synchrony with a tactile and visual prompt, minimizes false-trigger events while maintaining fast input during situational impairments. Results from a 12 person evaluation of the system, used to respond to notifications on the watch during walking and simulated driving, show interaction speeds of 4.0 s - 5.5 s, which is comparable to the swipe-based interface control condition. SeeSaw is also evaluated as an input interface for watches used in conjunction with a head-worn display. A six subject study showed a 95% success rate in dismissing notifications and a 3.57 s mean dismissal time.