Exploring tilt for no-touch, wrist-only interactions on smartwatches

Because smartwatches are worn on the wrist, they do not require users to hold the device, leaving at least one hand free to engage in other activities. Unfortunately, this benefit is thwarted by the typical interaction model of smartwatches; for interactions beyond glancing at information or using speech, users must utilize their other hand to manipulate a touchscreen and/or hardware buttons. In order to enable no-touch, wrist-only smartwatch interactions so that users can, for example, hold a cup of coffee while controlling their device, we explore two tilt-based interaction techniques for menu selection and navigation: AnglePoint, which directly maps the position of a virtual pointer to the tilt angle of the smartwatch, and ObjectPoint, which objectifies the underlying virtual pointer as an object imbued with a physics model. In a user study, we found that participants were able to perform menu selection and continuous selection of menu items as well as navigation through a menu hierarchy more quickly and accurately with ObjectPoint, even though previous research on tilt for other mobile devices suggested that AnglePoint would be more effective. We provide an explanation of our results and discuss the implications for more "hands-free" smartwatch interactions.