How the Sensor Works
The Vernier CO2 Gas Sensor measures gaseous carbon dioxide levels in the range of 0 to 10,000 ppm (Low range setting) or 0 to 100,000 ppm (High range setting) by monitoring the amount of infrared radiation absorbed by carbon dioxide molecules. Carbon dioxide gas moves in and out of the sensor tube by diffusion through the twenty vent holes in the sensor tube. The sensor uses a small incandescent light bulb to generate infrared radiation (IR). The IR source is located at one end of the sensor’s shaft. At the other end of the shaft is an infrared sensor that measures how much radiation gets through the sample without being absorbed by the carbon dioxide molecules. The detector measures infrared radiation in the narrow band centered at 4260 nm. The greater the concentration of the absorbing gas in the sampling tube, the less radiation will make it from the source through the sensor tube to the IR detector. The detector produces a voltage that is converted to ppm (parts per million) by the software.