LED-based gas sensors: A review

Swart, H.C.; Motaung, D.E.

doi:10.1016/j.coesh.2023.100506

Cited by 1 publication

(1 citation statement)

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“…MEMS microphones are commercially available and can be operated for many years with no detectable ageing signs, as they are being used extensively in the mass market of telecommunication devices. In addition, commercially available high-power LEDs currently operate continuously and reliably over long time periods of several months while consuming low energy levels [ 19 ]. PA sensors have been mainly used as indoor air quality sensors and are mostly executed as one-chamber PA systems, which shows high cross-sensitivities to humidity and other present gases.…”

Section: Introductionmentioning

confidence: 99%

Towards a Miniaturized Photoacoustic Sensor for Transcutaneous CO2 Monitoring

El-Safoury,

Weber,

Yassine

et al. 2024

Sensors

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A photoacoustic sensor system (PAS) intended for carbon dioxide (CO2) blood gas detection is presented. The development focuses on a photoacoustic (PA) sensor based on the so-called two-chamber principle, i.e., comprising a measuring cell and a detection chamber. The aim is the reliable continuous monitoring of transcutaneous CO2 values, which is very important, for example, in intensive care unit patient monitoring. An infrared light-emitting diode (LED) with an emission peak wavelength at 4.3 µm was used as a light source. A micro-electro-mechanical system (MEMS) microphone and the target gas CO2 are inside a hermetically sealed detection chamber for selective target gas detection. Based on conducted simulations and measurement results in a laboratory setup, a miniaturized PA CO2 sensor with an absorption path length of 2.0 mm and a diameter of 3.0 mm was developed for the investigation of cross-sensitivities, detection limit, and signal stability and was compared to a commercial infrared CO2 sensor with a similar measurement range. The achieved detection limit of the presented PA CO2 sensor during laboratory tests is 1 vol. % CO2. Compared to the commercial sensor, our PA sensor showed less influences of humidity and oxygen on the detected signal and a faster response and recovery time. Finally, the developed sensor system was fixed to the skin of a test person, and an arterialization time of 181 min could be determined.

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Section: Introductionmentioning

confidence: 99%