A General-Purpose Small RFID Epidermal Datalogger for Continuous Human Skin Monitoring in Mobility

Skin sensors based on Radiofrequency Identification enable non-invasive monitoring of human physiologic parameters. To speed up the experimentations of new sensing modalities and their possible applications, a general purpose on-skin oriented board is here described. A 3 cm by 3 cm flexible Kapton layer hosts a miniaturized open-loop antenna tunable in the worldwide UHF RFID band (860-960)MHz, a microchip with internal ADC and pads for interconnecting external sensors and a battery for data-logging mode. The epidermal board can be integrated into plasters and is suitable to measure both skin and external parameters. When working in Battery Assisted Passive mode it can be read up to 1.5 m and hence the wearer can automatically upload the stored data in mobility on crossing a gate. The device is preliminarily experimented in the measurement of the temperature of the skin and of the moisture on clothes.