Light Pipe Adapter for Raspberry Pi 3 Model B

thingiverse

This adapter is designed to move Raspberry Pi Model 3B LEDs to a front panel when integrating it in an enclosure. It fits highly affordable 1mm diameter PMMA light pipes, also known as fiber optics, and provides a reasonably bright display at the far end. The main use is to check if the SD card is active when powering down the Pi with a soft power switch before cutting the main power. A small panel mount light pipe adapter is included with a matching nut. Thread type is 1/4" ACME since it's very easy to print. It will fit in a 6 mm hole if your drill is sloppy. After printing, ream the holes with a 1-1.1mm drill to clear out printing gunk. After pushing the pipe through, I suggest grinding the ends flat. That improves light coupling and significantly improves the look of the exterior end since it's more omnidirectional. The easiest way to do this is to use a dremel with the standard drum-sander accessory at 10k rpm or more. Since the end is often widened a bit from this process, it's best to do it after pushing it through the printed adapter. (Some Loctite 401 super glue at the end works well for retention), hot glue can be used but it will melt the light pipe slightly and make it easy to bend. *Update*: Super glue makes the PMMA pipe extremely brittle so I suggest avoiding it. Hot glue, silicone or just relying on friction fit should be fine. The ID of the mounting hole is 3mm to clear the 2.5mm hole of the Pi; the height is 5 mm so a longer screw than normal will be needed (M2.5x10 should be fine with a 6mm hex spacer).