BodSockets: Enabling Back-of-Device Interaction on Smartphones with Socket-based Interface

We present BodSockets, an interface utilizing the form factor of collapsible phone grips, which is a smartphone accessory. BodSockets enables Back-of-Device interaction on smartphones through gestural input. We clarified the usage patterns of off-the-shelf collapsible phone grips through a crowdsourced study (N=300). Based on these findings, we prototyped BodSockets with 56 gestures categorized into IMU-based, touchscreen-based, and combined gestures. Our gesture recognition system achieved an accuracy of 91.5% for IMU-based, 91.0% for touchscreen-based, and 90.1% for combined-based gestures, respectively. Through a workshop, four promising use cases of BodSockets were revealed: (1) improving one-handed interaction; (2) reducing repetitive operations; (3) enabling error-free smartphone operation by utilizing both front and back inputs; and (4) enhancing intuitiveness and physical engagement through elastic feedback. Finally, we discuss the implications of our findings for the design of BodSockets-based interfaces.