Hi,

I have a tinkerforge weather station to which I added a CO2 bricklet, among other sensors. Recently, the CO2 bricklet has started displaying inaccurate values, sometimes dropping to 0 ppm, even though the minimum reading should be around 400 ppm. Do you have any idea what might be causing this issue? Should I consider replacing the bricklet?

As far as i understand how the CO2 sensor we use works, it should automatically recalibrate itself to ~400PPM after some time:

Zitat

The automatic self-calibration (ASC) algorithm autonomously generates a reference value by analyzing the measured CO2 concentration over a period of time.

The correct application of ASC requires the SCD30 to be regularly exposed to air with CO2 concentration = 400 ppm, as is the case in well ventilated buildings over night without human presence.

So when the sensor sees a specific PPM concentration regularly, it will calibrate itself towards this value being 400 PPM.

Yes, it used to calibrate to 400 ppm and it didn't drop below that. But now it drops to 0 ppm. It's been like that for weeks. Note that the values still vary in a meaningful manner, but the minimum value is now 0 ppm rather than 400 ppm.

bearbeitet September 11, 2024 at 08:5411. Sep 2024 von Wailer

Strange. Have you tried turning it off for a a few hours and then on again?

Yes, I did and it's still the same.