Low-Cost Sweating-Rate Sensor for Dehydration Monitoring in Sports

A total-cumulated-sweat/sweating-rate sensor for real-time monitoring of athletes' hydration is presented. Fabricated on flexible substrates using techniques compatible with rollto-roll production, the sensor features a total area of 13.7 cm(2), a sweat-volume capacity of approximately 28 mu L, and it is suitable for monitoring sweating rate for more than 39 minutes. Design aspects are discussed using Finite-Element Method simulations, and analysis is provided regarding the influence on the sensor response of skin and structural materials variability. The sensor employs a simple capacitive transduction method, with a novel interleaved electrodes array configuration, which allows the sensor to be operable without calibration. Characterization shows the sensor operability under moderate bending conditions, hence showing to be a good candidate for wearable applications.