A scalable, and tunable braided yarn for micro and macro physiological sensing

Future wearables envision a fully integrated sensing system capable of monitoring vital signs and biomechanics in daily environments. Currently, achieving a balance between imperceptible sensing and seamless integration poses a significant challenge to developing durable and personalized wearable solutions. In this article, we report an ultra-thin, miniaturized, capacitive braided composite yarn (CBCY) that is scalable and tunable for both micro and macro sensing applications. By leveraging advanced braiding and winding techniques, we created a sensor that is conformable, robust, and can be seamlessly integrated into the flexible surface. To elucidate the sensor, we characterized its capabilities and provided comprehensive guidelines for diverse use cases. Additionally, to evaluate the sensor performance, two wearable applications are designed to monitor human respiration (micro-sensing) and elbow movements (macro-sensing). Our braided yarn offers a new array of features for wearable designers, ensuring imperceptible comfort and the unification of sensors and electronics for future smart textile applications.