Update This post is now deprecated. It has been superseded by Using ESPHome with the Treatlife DS03 from 2022-06. UPDATE: (2021-10-22): Tasmota 9.5.0 has been superseded by the new Tasmota 10.0.0 release. This release works perfectly with the rules/automation outlined below; you no longer need to avoid the problematic 9.5 release with the DS03. I am extremely grateful to every one of the people that contributes to the Tasmota project to keep it improving!
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.