Study on the Development of a MEMS Hotplate-based Photoacoustic CO2 Sensor | Chapter 08 | Novel Perspectives of Engineering Research Vol. 5

 Instead of using a micro-electro-mechanical system (MEMS) hotplate for metal oxide semiconductor (MOS) or nondispersive infrared (NDIR) gas sensing, a photoacoustic (PA) hotplate was used. This MEMS hotplate PA carbon dioxide sensor was created using a low-cost MEMS microphone. This is the first time, to the authors' knowledge, a MEMS hotplate and a MEMS microphone have been combined for use in gas sensing with a high modulation frequency. In comparison to the MEMS microphone employed in this study, NDIR sensors use far more expensive photodetectors. MEMS hotplates and microphones have a number of attractive characteristics, including low power consumption, small size, and low cost. Metal oxide sensors and infrared emitters for gas sensing frequently use micro hotplates. Low power consumption, small size, and low cost are all desirable qualities of MEMS hotplates and microphones. As a blackbody, the hotplate is a good infrared emitter, appropriate for detection in the absorption band. Despite the large loss of radiation power due to the high modulation frequency, the remaining/reduced power radiation power was still sufficient to excite molecules for the formation of PA signals. The sensor's temperature study revealed that the PA signal diminishes as the temperature rises, implying that temperature effects must be compensated for. This research provides an alternative optical gas sensing system that is less expensive than traditional NDIR sensors and uses easily mass-produced components, making it a vital addition to the fight against air pollution and global warming.

Author(S) Details

Lucky A. Ishaku
Department of Electrical and Electronic Engineering, Blackpool and The Fylde College, FY2 0HB, United Kingdom.

David Hutson
Institute of Thin Films, Sensors and Imaging, University of the West of Scotland Paisley, PA1 2BE, United Kingdom.

Des Gibson
Institute of Thin Films, Sensors and Imaging, University of the West of Scotland Paisley, PA1 2BE, United Kingdom.

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