I made this for my Elegoo Centauri Carbon 3D printer because the stock lighting was so poor. My Centauri has an unused 24V lighting connector on its mainboard so I connected an LED strip, Amazon item B0DQ85JZW6, and removed the defuser/cover from the strip. I applied some aluminum tape to the inside of the hood to act as a reflector, and I glued a couple of magnets to the hood to hold it in place inside on the printer's side panel, just below the level of the extruder.

UPDATE: this has been superseded by this model: https://www.thingiverse.com/thing:7066620