Low power virtual sensor array based on a micromachined gas sensor for fast discrimination between H 2, CO and relative humidity

Abstract

A micromachined metal oxide gas sensor operated with temperature modulation allows discrimination between air, H 2 and CO in less than 1 s. Furthermore, the actual humidity level and gas concentration can be estimated. We tested gas concentrations of 3–12 ppm H 2 and 12–100 ppm CO at five relative humidity levels between 30 and 70%. While H 2 can be identified for all concentrations, certain identification of CO requires concentrations above 20 ppm and also determination of the relative humidity level from the sensor data.