PoE powered Stack Light

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.