Temperature effects on photoacoustic carbon dioxide sensor developed using mid-IR LED

The demand for low-cost, small size and low power consumption gas sensors that can have long operation life is on the rise. This paper presents a work on the effect that temperature has on a type of these sensors. It is a novel resonant photoacoustic carbon dioxide sensor made from mid-IR LED and MEMS microphone. Results obtained from the sensor show that there is photoacoustic (PA) signal loss when temperature increases. Also, higher temperatures decrease the sensor's sensitivity and quality factor but cause a proportional increase on the resonance frequency. The results show that the effect of temperature on photoacoustic sensors is significant and has to be taken into account at the design stage and compensated. This aspect would be a major objective of future work. However, change in resonance frequency caused by temperature variation was tracked throughout the measurement to ensure that the sensor was operated in the resonant mode, which offers the advantage of natural signal amplification.