Flexible pH Sensor for Wireless Monitoring of the Human Skin from the Medimun Distances

Sweat monitoring is an effective procedure to detect early signs or precursors of some psychophysical diseases. A compact wireless flexible on-skin pH sensor is here proposed for integration with Radiofrequency Identification in the UHF band. The peculiarity is its simplicity and minimal amount of required electronic components. The device comprises a printed multilayer pH sensor and an energy harvesting antenna optimized for application onto the human skin. Preliminary experiments demonstrated that the device is capable to capture a pH range compatible with physiologic data and to exchange data up to 1m without need of battery.