CapCrown: Enhancing Smartwatch Interaction by Detecting Fingers when Rotating the Crown Using Capacitive Sensing EICS002

Smartwatch interaction is typically limited by the device’s compact design and restricted input capabilities. Using the touch display occludes visual content, and for additional physical controls (e.g., buttons, bezel, crown) space is constrained. This paper enhances smartwatch interaction by expanding the functionality and thus increasing the input bandwidth of the crown. Initially, we investigate how users engage with a crown using two different numbers of fingers. Our informative study shows that crown rotation with one finger is faster compared to using two fingers. However, two-finger usage reduces the overshoot amplitude as well as number of fine-grained correction movements in a selection task. Subsequently, we develop a concept and a prototype that differentiates the number of fingers used in the crown interaction, which we call CapCrown . Finally, we discuss a set of applications that utilize this enhanced crown given the differences in interacting with one vs. two fingers. Our contributions include the study on crown interaction with different fingers, the sensor hardware, and the software using machine learning to detect fingers rotating a crown. Finally, we propose new smartwatch applications and system-wide functions that take advantage of our approach.