-Primary Test: Start the software and identify your sensor, if necessary. Let the sensor warm up for at least 180 seconds before continuing. Blow directly on the shaft of the sensor. You should see an increase in CO2 levels.
-Secondary Test: If the CO2 Gas Sensor is not giving reasonable readings in the Primary Test, try calibrating it. This should ideally be done outside in fresh air (which should be close to 400 ppm). Fill the 250 mL Nalgene bottle to the brim with water, take it outside, and dump the water to ensure it is then filled with fresh air. While still outdoors, insert the sensor into the bottle that now contains fresh outside air. Take the bottle and sensor to where the calibration will be done.
Start the software and connect your sensor. Let the sensor warm up for at least 180 seconds before continuing.
When the sensor has warmed up (readings should have stabilized), calibrate the sensor using a one-point calibration. Enter a value of 400 ppm for the sample of air collected. Once finished, the sensor should read very close to 400 ppm.