Dehydration is common and often underdetected in older adults, yet most remote patient monitoring (RPM) systems do not include hydration tracking. This project investigates the feasibility of a low-cost, non-invasive wearable patch designed to detect relative changes in hydration using skin-adjacent temperature and relative humidity sensors. The device is controlled by an Arduino-based microcontroller and emphasizes accessibility through inexpensive, open-source components.

A proof-of-concept study is conducted using bench-top models and self-testing to avoid regulatory constraints. Sensor outputs are evaluated under controlled conditions simulating varying hydration levels and compared against surrogate measures. Expected results include small, consistent decreases in skin temperature and larger decreases in relative humidity as hydration declines. While not intended for clinical diagnosis, this project demonstrates the potential for integrating simple hydration sensing into affordable RPM systems.