Each neopixel on the Circuit Playground's face lights one strand of light pipe, creating a gorgeous animated twisty twirly rainbow.  The code we included is a simple rainbow animation, and you can customize it however you like.  There's plenty of space on the Circuit Playground to add lots of color modes or animations, and they'll pretty much all look amazing.

Sculpting the horn took a few tries to get right, so you may want to order a few extra lengths of light pipe, even if you're super crafty.  

My horn ended up about 6" long, so with a little extra for the twists and to have enough to trim evenly below the lid, I used around 80" of light pipe.  The Flammi shoelaces I ordered are about 30" long, so it took almost three full laces.   They come in pairs, so be sure to order at least two sets.

Decide how tall you'd like your horn to be.  Add a couple inches to that measurement and cut 10 pieces of light pipe to that length.


Thread the light pipe through the 10 holes on the Circuit Playground cover and hold them over the Circuit Playground to make sure all your light pipe is working with no kinks.

Pull each piece of light pipe through about another inch further than needed to reach the NeoPixels.  When you twist the horn, the pipe will get pulled back out a little bit, so make sure you've got lots of extra.  We'll trim it to the perfect length later.

Time to get artsy.  Get out your heat gun and a pair of protective gloves.


Twist and gently heat the light pipe with your heat gun.  It will hold its shape as it cools.  Take your time and go slowly!  If you get the light pipe too hot it will melt and warp and cease to carry light very well.  Be patient!


I'm not very patient.  After two or three discarded tries, I began using a tumbler of ice water for cold plunges, and had a bit more success.   

To finish it off at the top, I trimmed each piece of light pipe slightly longer than the last in a spiral, and carefully melted them together.  I left the very last piece extra long, then melted it with the heat gun and pulled, stretching it into a perfect point.

Use a sharp pair of scissors or snips to trim the underside of the light pipes to 3mm, so they just touch the neopixels when the Circuit Playground is encased in its 3d housing.

This guide was first published on Jun 16, 2017. It was last updated on Jun 16, 2017.

This page (Unicorn Horn Assembly) was last updated on Jun 12, 2017.

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