Wireless Real Time Sweat Secretion Monitoring using Waveguide-based Wearable Sensor

Rising demand for wearable health monitoring and diagnostic devices necessitates the development of a reliable, real-time sweat rate monitoring method to optimize physical performance and prevent dehydration risks. This work presents a microwave waveguide probe-based sweat monitoring sensor integrated with a flexible 3D-printed sweat patch for real-time monitoring of sweat volume and rate. The waveguide-based sensor operates by monitoring the variations in the resonant response of the sweat patch, caused by the accumulation of sweat within the 130 µL microfluidic channel. The developed system demonstrates a resonant frequency decrease of ∼140 MHz upon the influx of the sweat sample into the microfluidic channel. The sweat sensor is capable of detecting and distinguishing different sweat influx rates into the channel, indicating its capability to quantify sweat rate. The system provides a low-cost reusable alternative to existing methods, in addition to its real-time continuous quantitative measurement capabilities without requiring patient-specific device calibration. The developed system promises its future potential as a sweat diagnostic tool for personalized health monitoring, with applications in telehealth and medical diagnostics.