Battery-Free. Sticker-Like, Device for Health Monitoring, Operated by Optical Power Transfer

This work presents the concept of a battery-free, sticker-like, device for a non-invasive health-monitoring sensor. The device consists of two functional blocks: an optical power-transfer block and an amperometric measurement block. The former accumulates power from a series-connected photovoltaic cell in a capacitor and intermittently supplies the power to the amperometric measurement circuit. This circuit is driven by powering pulses and displays the amperometric current as the durations of the light pulses from a light-emitting diode. The function of the circuit was successfully demonstrated through simulations, in which the equivalent circuit of an electrochemical glucose sensor was used as an example. The simulation results showed that the proposed device would work as expected for a variety of glucose concentrations at an oxidation voltage of 0.8 V.