Design and evaluation of a miniaturized no-nresonant photoacoustic CO₂ gas sensor with integrated electronics

This paper presents a miniaturized non-resonant photoacoustic CO2 gas sensor with integrated electronics. The photoacoustic sensor (PAS) consists of a black body IR emitter, an appropriate optical filter, and a highly sensitive microphone, which converts the generated acoustic waves to electrical signals. The integrated electronics unit facilitates a standalone PAS sensor system, controls and powers the system components, and processes the electrical signals to provide a corresponding CO2 gas concentration. The performance of the developed CO2 PAS is evaluated and characterized. The measurements are done in the range of 0-9000 ppm. A sensitivity of 0.074 mu V/ppm is achieved in the concentration range of 0-1537 ppm. For such a miniaturized non-resonant PAS sensor, the theoretical limit of detection (LOD) reaches 2.2 ppm for a sampling time of 330 seconds. Considering the cost, size, and performance, this sensor demonstrates the considerable potential for accurate and reliable indoor air quality monitoring.