Stretchable, Breathable, and Washable Fabric Sensor for Human Motion Monitoring

Abstract Wearable strain sensors for movement tracking are a promising paradigm to improve clinical care for patients with neurological or musculoskeletal conditions, with further applicability to athletic wear, virtual reality, and next‐generation game controllers. Clothing‐like wearable strain sensors can support these use cases, as the fabrics used for clothing are generally lightweight and breathable, and interface with the skin in a manner that is mechanically and thermally familiar. Herein, a fabric capacitive strain sensor is presented and integrated into everyday clothing to measure human motions. The sensor is made of thin layers of breathable fabrics and exhibits high strains (>90%), excellent cyclic stability (>5000 cycles), and high water vapor transmission rates (≈50 g/h m²), the latter of which allows for sweat evaporation, an essential parameter of comfort. The sensor's functionality is verified under conditions similar to those experienced on the surface of the human body (35°C and % relative humidity) and after washing with fabric detergent. In addition, the fabric sensor shows stable capacitance at excitation frequencies up to 1 MHz, facilitating its low‐cost implementation in the Arduino environment. Finally, as a proof of concept, multiple fabric sensors are seamlessly integrated with commercial activewear to collect movement data. With the prioritization of breathability (air permeability and water vapor transmission), the fabric sensor design presented herein paves the way for future comfortable, unobtrusive, and discrete sensory clothing.