SkinLink: On-body Construction and Prototyping of Reconfigurable Epidermal Interfaces
SkinLink: On-body Construction and Prototyping of Reconfigurable Epidermal Interfaces
We present SkinLink, a reconfigurable on-skin fabrication approach that allows users to intuitively explore and experiment with the circuitry adjustment on the body. SkinLink comprises tiny distributed circuit modules and a variety of streamlined trace modules that adapt to diverse body surfaces.
Applying customized epidermal electronics closely onto the human skin offers the potential for biometric sensing and unique, always-available on-skin interactions. However, iterating designs of an on-skin interface from schematics to physical circuit wiring can be time-consuming, even with tiny modifications; it is also challenging to preserve skin wearability after repeated alteration. We present SkinLink, a reconfigurable on-skin fabrication approach that allows users to intuitively explore and experiment with the circuitry adjustment on the body. We demonstrate SkinLink with a customized on-skin prototyping toolkit comprising tiny distributed circuit modules and a variety of streamlined trace modules that adapt to diverse body surfaces. To evaluate SkinLink's performance, we conducted a 14-participant usability study to compare and contrast the workflows with a benchmark on-skin construction toolkit. Four case studies targeting a film makeup artist, two beauty makeup artists, and a wearable computing designer further demonstrate different application scenarios and usages.
Publication:
SkinLink: On-body Construction and Prototyping of Reconfigurable Epidermal Interfaces
Pin-Sung Ku, Kunpeng Huang, Nancy Wang, Boaz Ng, Alicia Chu, and Hsin-Liu Cindy Kao.
Proceedings of the ACM on Interactive, Mobile, Wearable and Ubiquitous Technologies (IMWUT) June 2023
PDF I DOI
Project Credits: Hybrid Body Lab at Cornell University, directed by Cindy Hsin-Liu Kao
Research Team: Pin-Sung Ku (Lead Researcher), Kunpeng Huang, Nancy Wang, Boaz Ng, Alicia Chu, and Prof. Hsin-Liu Cindy Kao (Lab Director).
THIS PROJECT WAS SUPPORTED BY NSF UNDER GRANT IIS#2047249
SkinLink proposes adaptive trace modules made by braiding thin conductive wires on various core fibers.
14 SkinLink circuit modules with sensing, computing, actuation, and communication functions. A penny is shown for scale reference.
Usability study comparing two on-skin contruction toolkits: (a) SkinLink materials and (b) SkinKit materials.
14 participants created on-skin prototypes using SkinLink (left), and SkinKit (right). Symbols on the top right corner represent the type and amount of trace modules used in the SkinLink prototype, and the number in the diamond shape symbol denotes the amount of SkinKit wire modules used.
Case studies collaborated with makeup artists: (a) A heartbeat on the cheek. Moldable trace modules were winded to create intricate patterns paired with silicone prosthetics. The circuit consists of a time-of-flight sensor and a haptic driver. (b) Hidden proximity alarm on the forearm. Using a skin-tone foundation to camouflage the circuit with a thin layer of prosthetic skin, four LED modules will light up gradually when the proximity sensor detects an object getting closer.
Case studies (a) integrated on-skin circuitry in a hybrid form of filigree-like jewelry shaped with copper wire. The device can monitor the user’s posture with an IMU sensor, which creates vibration feedback from the two haptic drivers when the user slouches. (b) Strength training posture trainer comprising a Bluetooth module, an IMU sensor, a proximity sensor, and three LEDs on the thigh.
SkinLink consists of a customized construction-based toolkit and a workflow, inspired by SFX prosthetic makeup, for fabricating, applying, and blending the interface with the wearer’s body for creating on-skin prototypes. To support the on-skin fabrication workflow, SkinLink leveraged a modular circuit design, where an on-skin interface is built upon connecting multiple single-function flexible printed circuit boards (FPCBs). SkinLink modules are unique because they are engineered for comfortable skin-wearability and robust circuit connections on various body locations. We contribute a range of stretchable connectors specifically suitable for linking the on-skin circuitry and withstanding body movements.
The Hybrid Body Lab collaborated with an innovative tinsel wire manufacturer, Maeden, to develop the stretchable trace module. The conductor is fabricated with a single TPU elastic fiber. Two sets of copper wires (two-wire inner layer and four-wire outer layer) are rotationally braided in clockwise and counter-clockwise directions. The stretchable trace module is well-suited for mobile body locations, including the elbow, the knee, and the fingers.