MQTT on karl

Converting PurpleAir Classic to ESPHome

Sat, 20 Jun 2026 00:00:00 +0000

Converting a PurpleAir Classic to ESPHome

I still don’t 100% know what the issue is but for the past several months, my PurpleAir Classic sensor has been incredibly flakey when it comes to reporting data. Home Assistant would report random bouts of “timeouts” while trying to poll the sensor and that would result in gaps in the data. In the best case, the gaps were only a few minutes long but sometimes they would last for hours at a time.

PoE powered Stack Light

Sun, 28 Feb 2021 00:00:00 +0000

The lights are much brighter than they appear in this picture; had to intentionally darken the image to prevent camera from blowing out the colors.

Stack/signal lights are everywhere in industrial applications for good reason: they’re a compact and relatively information-dense indicator system. They always seemed like the kind of indicator that only people with expensive machines needed. Until I found that they can be had for just under $6/light from Ali Express, that is.