Dynamic LED Fiber Optic Star Display

This is a guide on creating a dynamic LED fiber optic star display. I made a dynamic star field infinity mirror art piece, but these instructions can also be used to make a dynamic star ceiling or a static star display. The stars have a wonderful pin point quality that can be programmed to display any color and animated to twinkle or pulse. Unlike other star displays, I use an LED strip with custom attachments instead of a typical fiber optic illuminator. With Arduino programming, the options are limitless for triggers and animations.

ADVICE: Test everything! This is especially important when you're working with new materials. For example, I tried 4 different adhesives for my fiber optics and ended up using hot glue which still wasn't the best solution because it would warp the fiber optic strands.

Materials

• Adafruit Metro M0 Express
• Neopixel RGBW strip (silicone sleeve preferred)
• Fiber optic strands
• Solder
• Wires
• Zip ties
• Hot glue
• Heat shrink (or electrical tape)

Tools

• 3D Printer
• Something to make small holes in your material (I used a laser cutter but a drill would do)
• Soldering iron
• Hot glue gun

You first need to decided how your star display will look and what it will be in or on! I made a frame for mine, but you could use an existing box, closet, ceiling, etc. These displays look best in the dark, so I recommend that it's somewhere that you can control the lighting and against a dark surface.

Also, a little bit of fiber optics goes a long way. I bought a 9.8ft 300 piece bundle of strands, used about 2/3 of it, and would've been okay with 1/3. So take the time to do the math to make sure everything will fit in whatever you're housing your display in, because too many strands becomes a cable management nightmare!

Shown above is the basic circuit diagram for my build. My build is triggered by audio, but you can add a variety of triggers or sensors to trigger your strip animations. The neopixel strand test is a good place to start to decide what you want displayed.

Fiber optics work by directing light through transmissive strands. This works with any visible light, but works best when one end of the strand is directly aligned with a light source. In order to achieve this with an LED strip, I modeled and 3D printed custom strand clips.

The 3D models that I attached to this Intractable hold about 10 strands each and fit the 60 LED/meter Adafruit NeoPixel LED Strip with silicone case. These clips are printed in two parts to account for overhang print issues. After you determine how many LEDs you plan on utilizing, you can start printing!

Once the print is done, you can start assembling. I utilized 19 pixels in the end so I printed 21 clips to make sure I had enough. Depending on your printer's tolerance, the peg portions of the clips may be tight. I found that pushing them through the back side of the clip worked best, and used the end of a lighter to push it through flush.

The fiber optic assembly is tedious, but simple. Start by counting out the first 10 (or however many you're using) strands. I used about an inch of heat shrink to bind the strands together. The major obstacle with this method is that fiber optic strands are extremely sensitive to temperature. If they get too hot, they will melt and lose some of their transmissive properties.

Once the strands are bound, you can insert the group into the 3D printed clip and secure it with a zip tie. When all clips are assembled, they can be attached to the LED strip. You'll need to align each clip to ensure they're directly over the LEDs.

For my build, I laser cut 204 holes into sheets of PET with mirror finish. I then adhered these to white foam board, and punched those holes through with a pin.

Depending on your material, you may be able to use a drill or thick pin to create your holes.

You can now thread the fiber optic strands through the holes! This was time consuming since I had much more strand length than I needed. I secured the strands with hot glue. Again, be warned that fiber optic strands are sensitive to temperature. The hot glue gun I used had a low temperature setting, but even then it still warped the strands if I didn't allow the glue to cool.

What I ended up doing was apply a bead of hot glue directly to the back side of the hole, wait for the glue to cool, and thread the fiber optic strands through. This wasn't ideal so if you have better ideas of how to secure fiber optic strands don't hesitate to add it in the comments!