Porous Silicon-Based Microspectral Unit for Real-Time Moisture Detection in a Battery-less Smart Mask

We report on a battery-free smart mask that can monitor the health of the wearer's lungs. Analysts containing the moisture content of the exhaled breath are detected using porous silicon (PS) photonic array. The PS photonic sensor array changes the emission wavelength and intensity of a PS photonic device's photoluminescence (PL) in response to ambient humidity when exposed to 365 nm UV light. A microspectral unit incorporated into the sensor platform captures changes in PL spectra. Near Field Communication (NFC) is used to ease data transmission to a nearby reader and power the entire sensing device. The moisture sensor (PS chip) is detachable and must be replaced every 8–10 hours of operation.