Who can recommend a good CO2 sensor?

[Wolli01]

I am looking for a CO2 sensor that I can connect to my Wipy/Lopy.
Does anyone already have something like this running and can tell me which library to start with?

Many thanks in advance for your help.

[thinginnovations]

I've had success with the Cozair sensors from Gas Sensing Solutions. At the time I started looking at CO2 sensors a couple of years ago they were pretty much one of the few and the lowest cost sensor. Now there are others available using the same technologies.

The sensor I have is now connected to a Lopy and Expansion board to provide regular readings via LoRa.

Andrew

[PeterB]

Note those CO2 sensors need to be calibrated regularly and assume a baseline of 400 ppm whether true or not. See specification.

[Martinnn]

CO2 sensors are expensive because they work by using the NDIR prinicple, which is more difficult to implement than sensors for more reactive gases (like CO). Check out the MH-Z14A or -Z19.
If you are after room air quality, there are air quality sensors ("VOC") that are less expensive.