Solder Free Options

If you are interested in making your own CO2 sensor, and don’t want to do any soldering there are options. For the solder free option, I’d recommend the Sparkfun Qwiic line.

With the options below and a USB 5V power source you will have a functioning CO2 sensor with display (No logging). To get logging, there are options to add a QWIIC based microSD card along with a QWIIC based RTC board (which you will need to set and keep time for your log).

Option 1: Simplest, Cheapest (But Least Accurate)

• Qwiic Pro Micro ($19.95 US) Canadian Link

• Environmental Breakout ($35.95) - eCO2 Canadian Link

• Alphanumeric Display ($9.95) Canadian Link

• Cables (qty 2) ($1.50) Canadian Link

Option 2: More accurate, but still solder free

• Sensirion Photoacoustic CO2 sensor ($49.95)

The Sensiron seems to be replacing the NDIR sensor with the photoacoustic version, as it is lower cost and only slightly less accurate +/- 50ppm vs +/- 30 ppm. I should note that the eCO2 sensors I have found do not publish specs on CO2 accuracy, which speaks volumes.

All prices and link above in USD, and will end up with shipping and duties charges. Mouser.ca also stocks some Sparkfun boards.

The SD40x sensor seems to be in short supply. The SCD30 sensor can also be used. It would require a small amount of soldering.

• Qwiic adapter board ($1.50) Canadian Link

• SCD30 ($59.95) Canadian Link