One of the things I’ve been wanting to do is make a batch of SAO style circuit boards with a CO2 sensor hooked up to a 7-segment display and hand them out to pe

One of the things I’ve been wanting to do is make a batch of SAO style circuit boards with a CO2 sensor hooked up to a 7-segment display and hand them out to people at conferences. This would give people a way to witness ambient CO2 levels first hand, and how much it’s increasing. I’d have a QR code on the back, write something like “getting hot enough for you?” and have it link to non-profits doing work on climate change. The idea would be to build a batch of a few hundred of these. If co2 sensors get down to the $5 price point, this idea starts to get feasible. Right now sensors are getting cheap, which is impressive, but not cheap enough yet to hand them out to strangers for free.