Design and Perception of a Soft Shape Change Beneath a Smartwatch

Abstract

We explore the design of a watch that can deliver notifications through shape changes, with a specific focus on changes in curvature at the back of the watch face. We explain our design choices and the challenges we faced while creating such a watch. We conducted an experimental study to determine the absolute detection threshold (ADT) of this novel form of feedback. We compared the ADT of two different watches, both of which have a back face that can change its curvature and make contact with the wearer's wrist to notify them. These two watches exhibit different shapes when inflated with high air pressure. To determine the ADT, we conducted a standard two-down, one-up adaptive staircase procedure. Our findings show that an ADT of 3.86 psi is required to inflate the back surface for detection by participants. Overall, our qualitative findings indicate that participants enjoyed this novel type of feedback and could feel different sensations with each watch.