As the name implies, carbon dioxide detectors sense the presence of CO2. Carbon dioxide is a naturally occurring chemical compound that is a critical part of the life cycle of plants and animals as well as a critical component of certain industrial processes.

Though an important component of life itself, carbon dioxide can also be dangerous. In concentrations above 7%, carbon dioxide can cause suffocation in humans. Carbon dioxide is also a major greenhouse gas with severe environmental implications.

Most commonly, carbon dioxide is measured using NDIR (non-dispersive infrared) sensors. NDIR sensors are spectroscopic sensors to detect CO2 in a gaseous environment by its characteristic absorption. Gas is pumped or diffuses into a light tube where the electronics measure the absorption of the characteristic wavelength of light. Results are displayed as a parts per million measurement.

Carbon dioxide meters are available as handheld units for spot checking or as fixed mount transmitters for continuous monitoring and with outputs for process control. The membrane switch provides the switch fuction with less weight and space, at a lower cost than most alternatives.