Assessing the role of textiles in the performance of wearable screen-printed strain sensors for breathing rate monitoring

Wearable sensors for breathing rate (BR) monitoring are gaining increasing interest in sports applications. Particularly, resistive strain sensors are being extensively studied, thanks to their ability to monitor BR by recording the movements of the chest wall during breathing cycles. In this work, wearable screen-printed BR resistive strain sensors were realized and characterized using two different commercial textiles, and for each of them a geometry with two different dimensions. To assess the characteristics of the four resulting textile-sensor combinations, cyclic electromechanical tests were performed. The results allowed to select the most suitable textile and sensor dimension for the specific application, which is characterized by a sensitivity of 22 ± 2%, good stability over time and negligible drift. The optimized device was then tested on a human subject, which demonstrated the possibility to realize a simple low cost wearable sensor for BR monitoring.