moxd lab at EICS 2026

We are looking forward to the ACM SIGCHI Symposium on Engineering Interactive Computing Systems. This year, the conference will be in Patras, Greece. We are happy to contribute our recent work on smartwatch interaction: CapCrown. The paper will be presented by David Petersen and Marvin Reuter. The work resulted from our continuation of the work we did on MultiKnob for enhancing rotary knobs and MultiBand for enhancing smartwatch interaction: with CapCrown we added additional input capabilities to smartwatch crowns.

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

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.

Petersen, David; Reuter, Marvin; Böhmer, Matthias: CapCrown: Enhancing Smartwatch Interaction by Detecting Fingers when Rotating the Crown Using Capacitive Sensing. In: Proceedings of the ACM on Human-Computer Interaction, vol. 10, no. 4, 2026. (Type: Journal Article | Abstract | Links) @article{petersen2026capcrown, title = {CapCrown: Enhancing Smartwatch Interaction by Detecting Fingers when Rotating the Crown Using Capacitive Sensing}, author = {David Petersen and Marvin Reuter and Matthias Böhmer}, url = {https://moxd.io/files/2026/05/petersen2026capcrown.pdf}, year = {2026}, date = {2026-06-08}, urldate = {2026-06-01}, journal = {Proceedings of the ACM on Human-Computer Interaction}, volume = {10}, number = {4}, abstract = {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.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Close 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. Close https://moxd.io/files/2026/05/petersen2026capcrown.pdf Close

We also have a repo on GitHub with some material for building the prototype and running the study.