Calibration
The CO2 measuring component within the AirSpot device is the SCD4x produced by Sensirion.
Each SCD4x sensor is factory calibrated. Normally, the sensor should not need frequent recalibration. It should stay correct for months or years. Something like a significant change of altitude might affect calibration.
When you first use your AirSpot, check its calibration by placing it in fresh air, away from people or other CO2 sources, for 10-30 minutes. It is normal for readings to vary by about 50ppm from one reading to the next but it should average around 420-450ppm in fresh air. If not, here’s how AirSpot can be re-calibrated:
You will see that the calibration page of the app allows a choice of automatic or manual calibration.
There is also a button to factory reset the sensor. It is possible that if it’s reading incorrectly, a factory reset of the sensor will restore proper readings.
Manual calibration
Manual calibration allows you to set the CO2 level present wherever you conduct the calibration. If you have another trusted CO2 meter, you can even calibrate indoors where the level is 500ppm by entering that as the “calibration target”. Otherwise, calibrate outdoors and do not change the target.
Before conducting manual calibration, place AirSpot in a location where the CO2 level is known and is not changing. Let it stabilise for 10-30 minutes. Set the target (if known) and tap the green icon. Calibration will take 4-10 minutes depending on the update frequency the device is set to. When the countdown reaches 0, AirSpot will briefly display the amount of correction it has applied. This could be a + or – value, or 0.
After this, you should see readings which average something close to the calibration target.
Auto calibration
If “Auto” is turned on, the sensor recalibrates itself every 7 days on the assumption that the lowest reading recorded is what the target is set to (by default 426ppm).
The app shows the date when the next correction will be made. It will also recalibrate itself at any time if CO2 readings drop below 400ppm.
Do not use auto unless you are sure your AirSpot will be exposed to fresh air every few days. If you keep it indoors in an area where the CO2 never drops below 550ppm, for example, it will calibrate itself to show 550ppm as 426ppm. If you take it on a plane flight with Auto turned on, it might calibrate itself incorrectly when the cabin pressure drops.
Auto calibration is best suited for situations where
· AirSpot is frequently powered, because a flat battery will restart the 7 day cycle.
· It’s frequently in a location where CO2 will drop to fresh air levels say every night or every weekend.
For more information on the latest AirSpot software release please click on this link: https://airspothealth.myshopify.com/a/blog/airspot-device-and-app-latest-software-release
