This just in: my friends chucked out a shitty "CO2" #sensor.
Actually a breathalyzer:
https://hackaday.com/2023/02/18/anatomy-of-a-fake-co2-sensor/
It's a really pretty design! And while the man in the video says it's useless, I actually started a CO2 sensor project this winter, but I didn't have a display or case.
Now I guess I do!
But it turns out driving a matrix of #LCD segments is surprisingly difficult.
Here's a picture of connections. Wish me luck figuring out.