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Comment by ahaucnx | Hacker News Reader

We maintain a popular open hardware air quality monitor that also uses a Senseair CO2 Sensor [1]. This gives you a lot of flexibility on how to use the data. The pre-soldered version is easy to build and also includes a PM sensor.

[1] https://www.airgradient.com/open-airgradient/kits/

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I'm wanting a Co2 monitor that works without cloud and looked at some of the sensors available.

Does the sensor in your project need to be taken outside to calibrate?

I stopped when I realised many sensors (like scd30/40) need this making it very impractical.. Has to be done once while powered on the whole time in a 7 day period.

I think pretty much all indoor air quality monitors with NDIR sensors have by default an automatic baseline calibration. Our kicks in every 7 days. So you should somehow reach ambient CO2 levels once a week to have it properly calibrated.

I don’t enable automatic calibration on my SCD30 because the algorithm basically assumes that the lowest ppm in the last 7 days is 400ppm and baselines to that. I just took mine outside once, set that to 400ppm and haven’t recalibrated it since. The drift on the sensor is supposed to be very low.

Looks like you don't sell the pro boards by themselves without the inclosure.

No, but the Gerber files are available on our instructions page.

So far people that were interested in the combination of enclosure and pcb or the whole kit.

Pricing out the parts buying third party and there's very little savings in doing so due to the cost of enclosure and the pbc especially the additional 24 to $30 shipping.

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