We present Vidgets, a family of mechanical widgets, specifically push buttons and rotary knobs that augment mobile devices with tangible user interfaces. When these widgets are attached to a mobile device and a user interacts with them, the widgets’ nonlinear mechanical response shifts the device slightly and quickly, and this subtle motion can be detected by the accelerometer commonly equipped on mobile devices. We propose a physics-based model to understand the nonlinear mechanical response of widgets. This understanding enables us to design tactile force profiles of these widgets so that the resulting accelerometer signals become easy to recognize. We then develop a lightweight signal processing algorithm that analyzes the accelerometer signals and recognizes how the user interacts with the widgets in real time. Vidgets widgets are low-cost, compact, reconfigurable, and power efficient. They can form a diverse set of physical interfaces that enrich users’ interactions with mobile devices in various practical scenarios
We thank the anonymous reviewers for their feedback, as well as Brian Smith and Lydia Chilton for their help on paper revision, Zixiaofan Yang for video recording and Henrique Maia for video narration. This work was supported by Snap Inc. It was done while Chang Xiao was an intern at Snap.