Skinergy: Machine-Embroidered Silicone-Textile Composites as On-Skin Self-Powered Input Sensors
Skinergy centers around the triboelectric nanogenerator (TENG) on-skin sensors which do not rely on external power for sensor operation. The sensing board, which still requires a battery, reads the signals generated by the sensor and transmits the signals wirelessly to a nearby computer for signal processing. Depending on the TENG electrode design, Skinergy is capable of discrete touch detection, multi-touch detection, contact localization, and gesture recognition.
We propose Skinergy for self-powered on-skin input sensing, a step towards prolonged on-skin device usage. In contrast to prior on-skin gesture interaction sensors, Skinergy's sensor operation does not require external power. Enabled by the triboelectric nanogenerator (TENG) phenomenon, the machine-embroidered silicone-textile composite sensor converts mechanical energy from the input interaction into electrical energy. Our proof-of-concept untethered sensing system measures the voltages of generated electrical signals which are then processed for a diverse set of sensing tasks: discrete touch detection, multi-contact detection, contact localization, and gesture recognition. Skinergy is fabricated with off-the-shelf materials. The aesthetic and functional designs can be easily customized and digitally fabricated.
Publication:
Skinergy: Machine-Embroidered Silicone-Textile Composites as On-Skin Self-Powered Input Sensors
Tianhong Catherine Yu, Nancy Wang*, Sarah Ellenbogen*, Cindy Hsin-Liu Kao ((*equal contribution)
Proceedings of The ACM Symposium on User Interface Software and Technology (UIST) 2023, October 29–November 01, 2023, San Francisco, CA, USA
Project Credits:
Hybrid Body Lab at Cornell University, directed by Cindy Hsin-Liu Kao
Research Team:
Tianhong Catherine Yu (Lead Researcher), Nancy Wang, Sarah Ellenbogen, Cindy Hsin-Liu Kao (Lab Director)
This project was supported by the National Science Foundation under Grant IIS-2047249 and Cornell Atkinson Center for Sustainability.
Sensing principle of Skinergy. (A): the single-mode TENGs topology; (B): our TENGs material selection; (C): the schematic of the contact-separation mechanism; (D): the schematic of the sliding mechanism. The contact-separation cycle generates AC signals as the finger touches and leaves the sensor. Sliding across the conductive thread generates AC signals as the finger moves towards and away from the electrode
To streamline the design process, users can design the shape (thick black lines), electrode placements (thin gray lines), and aesthetics (other lines, green, blue, and brown in this case) of Skinergy sensors in a single vector graphic file (.svg). Our python script then outputs the mold model (.stl) and the embroidery instructions (.pes) that can be directly used for 3D printing and machine embroidery, respectively.
Step-by-step fabrication workflow. (1) Prepare the embroidery substrate with PVC sheet and the tear-away stabilizer; (2) Embroider the design; (3) Tear away the stabilizer; (4) Cast silicone to fix the top thread in place; (5) Wash away the water-soluble stabilizer to remove the PVC sheet; (6) Cast silicone on the other side to fill the holes.
Gestures and corresponding example signals. The top left is the electrode design of the sensor. Colors map the electrode to the signals generated from it.
Example applications. (A) A forearm music player patch inspired by Takashi Murakami's flowers. (B) Discrete (right) and decorative(left) eyelid tapes that detect eye blinks. The visualized signals show that mechanical movements of the eyelids generate measurable electrical signals. (C) A behind-the-ear sticker for sending emergency notifications. (D) A wristband for remotely controlling home appliances.
Acknowledgments
We thank Chi-Jung Lee, Jingwen Zhu, Pin-Sung Ku, and Heather Kim for their inputs, and Xia Zeng and Charles V. Beach, Jr. for the technical support. We also would like to thank the study participants and the reviewers.