A Mobility Evaluation of Tilt Panning and Offset Sensing Smart Watch Input

Abstract

Small smartwatch touchscreens restrict input and researchers have long explored how alternative modalities and techniques can enable new possibilities and boost expressiveness. However, these techniques are generally designed in and for static, stable settings; mobility issues are rarely considered. To address this omission, we conducted a mobility study that compares two recently proposed alternative smartwatch input modalities: physical movements of a watch on the wrist, and an offset touch sensor on the edge of the device. We observed high selection errors for tilt input (23.89% to 34.22%) and prolonged times for offset sensing (>1000ms). We propose a combined input technique designed to fit the constraints of mobile watch use: touches to the device edge stabilize and constrain input, while tilt and touch control and trigger it. A second study shows this design can improve target selection time while mobile to less than 800ms with error rates of 10.2%.