How Does an NDIR CO2 Sensor Work? | isweek.com

SenseAir (Sweden) presents a new miniature low power NDIR CO2 sensor module, SenseAir S8 4B. The sensor can be integrated in a wide range of different alarm applications where you want to detect CO2, such as leakage detection.
SenseAir S8 4B main application area is to serve as a CO2 safety switch when built into equipment such as kerosene heaters and other equipment generating potentially hazardous levels of CO2 gas. Because of low current consumption the sensor is suitable for battery applications and has an average current consumption of 2 mA.
SenseAir S8 4B measures 400 to 32000 ppm and alarm when the CO2 level is higher than 8000 ppm and stay in alarm mode until CO2 levels are below 6500 ppm.
The sensor is designed for high volume production with full traceability by sensor serial number on all manufacturing processes and key components. All sensors are individually calibrated.
- See more at: http://www.envirotech-online.com/news/gas-detection/8/senseair/new_low_power_ndir_co2_sensor/19205/#sthash.yGvZ2YlW.dpufSenseAir (Sweden) presents a new miniature low power NDIR CO2 sensor module, SenseAir S8 4B. The sensor can be integrated in a wide range of different alarm applicaIn our industry, many of us use the term "NDIR CO2 sensor", without thinking about what it stands for, or how NDIR sensors actually work.

NDIR is an industry term for "nondispersive infrared", and is the most common type of sensor used to measure CO2, that is NDIR CO2 Sensor . 


An infrared (IR) lamp directs waves of light through a tube filled with air toward an IR light detector, which measures the amount of IR light that hits it. As the light passes through the tube, any gas molecules that are the same size as the wavelength of the IR light absorb the IR light light only, while letting other wavelengths of light pass through.

Next, the remaining light hits an optical filter that absorbs every wavelength of light except the exact wavelength absorbed by CO2.


Finally, an IR detector reads the amount of light that was not absorbed by the CO2 molecules or the optical filter.


The difference between the amount of light radiated by the IR lamp and the amount of IR light received by the detector is measured. The difference is proportional to the number of CO2 molecules in the air inside the tube.

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Of course, this is a very simplified explanation. If you want to learn more about NDIR, this Wikipedia article is a great place to start.tions where you want to detect CO2, such as leakage detection.

SenseAir S8 4B main application area is to serve as a CO2 safety switch when built into equipment such as kerosene heaters and other equipment generating potentially hazardous levels of CO2 gas. Because of low current consumption the sensor is suitable for battery applications and has an average current consumption of 2 mA.

SenseAir S8 4B measures 400 to 32000 ppm and alarm when the CO2 level is higher than 8000 ppm and stay in alarm mode until CO2 levels are below 6500 ppm.

The sensor is designed for high volume production with full traceability by sensor serial number on all manufacturing processes and key components. All sensors are individually calibrated.