S8 No Longer Returning Values

After a year or so of faithful work, I pulled in my DIY Airgradient kit to reprogram it to use MQTT instead of direct Prometheus support. And now I’m getting negative values for CO2 (-1, -2, and -3 respectively).

I touched up my solder work under the theory that a bad joint separated under the thermal and physical stress of being moved inside, but that hasn’t fixed it. Can these sensors just go bad after working for a while?

Normally they don’t break easily. It could also be a software issue. Can you flash the official software from our website and check if that works?

It appears to be related to the soft serial timing issues that have been discussed elsewhere. Switching over to a refactored branch of the Airgradient library has remediated the issue for CO2, but I am also having issues with my PMS sensor. I’m going to try a Wemos S2 to see if I can get hardware serial working.

Can you describe your exact issues with the PMS sensor? What I see is that the PMS generally runs pretty stable on SW serial.