Sensor Technology
Low-power gas sensor options for battery-powered IoT
By Neill Ricketts, executive chairman at Gas Sensing Solutions (GSS) T
he ability to detect the presence of (and change in concentration of) specific gases, even at low quantities, has long been important. Radon and carbon monoxide detectors have been commercially available since the 1980s and 90s. These were developed in response to significant and dangerous side effects, but the proliferation of Internet of Things (IoT) devices for optimizing environmental conditions means a wider range of gases can be monitored to control the environment.
is present in the atmosphere at 400-450 parts per million (ppm), and the gas is only immediately dangerous to life above 40,000 ppm. It is generally considered safe for prolonged exposure at levels up to 5,000 ppm (average). However, the gas can be a key correlate for multiple environmental or health issues. CO2
Among the most useful gases for wide-scale monitoring is carbon dioxide (CO2
). CO2
concentration relates to occupation density: a crowded room increases the chance of someone being infected. Studies showed increased levels of CO2
correlate
with increases in airborne viruses (including Covid-19), it also highlights decay of food in agricultural storage. Conversely, at specific concentrations, the gas can be used as a preservative when shipping, for example, salad bags. It is also crucial in maintaining the correct pH level in culture mediums for gametes and embryos in IVF. As anyone who has watched Apollo 13 will attest, CO2
sensing has been
possible for many decades – NASA used a tuning-fork mechanism energized by an electromagnet for this. Since then, IR absorption has been the best method, but even with incandescent bulbs this has remained too powerful for use in battery- powered IoT systems.
In this article we’ll examine how the gas can be monitored within the power budgets available to an IoT device and the key
44 October 2025 Fig 2: A schematic for an IoT CO2 Components in Electronics sensor for use in air quality monitoring
www.cieonline.co.uk Fig 1: Airborne substances can be identified by their absorption of IR at specific frequencies, with CO2 having an absorption signature at 4.25 microns
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