A selective, miniaturized, low-cost detection element for a photoacoustic CO2 sensor for room climate monitoring

We present a miniaturized, low-cost detection element for a photoacoustic spectroscopic gas sensor system. The sensing element consists of a commercial mobile phone microphone and a standard TO socket. The elements are mounted under gas atmosphere and serve as gas selective reference cell. The system is able to detect CO2 selectively with a resolution better than 100 ppm. Further characterization included different environmental conditions and gas cross-sensitivities. The potential for further miniaturization and the realization as a low-cost mass market sensor is shown.