[Hasz]

If you're interested in a hardware solution, I've used the MH-Z19 CO2 sensor to great results. It's an NDIR (read:not electrochemical) sensor with a UART interface and temperature compensation. It will report up to 5000ppm and comes factory calibrated.

It's also $20 in singles from China. Coupled with whatever microcontroller you want, it's totally possible to have a distributed net of CO2 sensors for a low cost per node.

That being said, it's a ton of work and this is an excellent solution with much quicker results.

[tga]

Just wanted to add that Tasmota[0] (one of the open source firmwares for ESP8266 controllers) seems to already support MH-Z19 sensors.

This cuts down on the work if all you want is to measure your CO2 level: you can get a $3 Wemos and a sensor, (solder pins, figure out the sensor connector), flash Tasmota, and you'll have it already reporting on MQTT over wifi. I would argue it's even easier than installing and maintaining Linux on a RPi.

[0] https://github.com/arendst/Sonoff-Tasmota

[antoniuschan99]

+1 for the MH-Z19.

We're looking to add a Co2 sensor to our IoT lineup and the MH-Z19 looks promising. It's also really small too :). You can also choose from 2 different ppm sensitivity from the factory and can get it on Aliexpress.

Here's the project I'm working on:

http://www.kokonaut.com http://www.instagram.com/kokonautweathersensors

[JoeDaDude]

Thank you for the tip! I was just thinking of adding a CO2 monitor to a homebrew Arduino weather station. I was looking at this device but calibration of CO2 sensors is an issue:

https://www.adafruit.com/product/3566?gclid=EAIaIQobChMI9uiy...

[simik]

Is there any significant difference between MH-Z19 and MH-Z19B?