CO2 sensor for air quality

hi, all

I have a complete arduino based domotica system up and running.
Now I would like to add a CO2 sensor to some rooms to control the air quality.

I already tried the MG811 modules by sainsmart but even with an opamp they do not seem to react to my breathing on them, let alone be able to measure CO2 levels in a room.
I have a feeling that when they start to work I'd be long dead :slight_smile:

So does anyone has any suggestions/experience?

Have no experience with this module, however, this link shows how to buffer and amplify the signal, connect it to the Arduino and also has sample code and test results: MG-811 CO2 Sensor Module | Sandbox Electronics

Hey, Dlloyd,

I have a board similar to this from sainssmart. It also uses the mg811 but it does not seem to work pretty well. I have a feeling the mg811 is not accurate enough for measurements inside a small room.

But I might be wrong.

so I was wondering if anyone had hands on experience with the MG811 or with any other sensor?

Looking at the datasheet (specifically the graph there with Sensitivity) it looks like it isn't much good below about 400ppm. Normal atmospheric CO2 is about that or maybe a little lower. So you're operating right on the edge of what that sensor is capable of unless you have significantly increased CO2 in the room.

Yeah, I know.

In principle "bad" air could go up to 1000ppm. But still.
I don't think the MG811 is the right way to go...

That's why i was wondering if anyone here had hands on experience with some other sensors.
I mean it is being used in all major brands. Even Nest has CO2 sensors. All between 100$ and 400$.

So it should be doable...

I found this one :

Anyone experience with this sensor?