Sometimes you want to add animated lights to your costume or project and you're really limited on space. Necklaces are a great example of this - a glowing pendant can be so striking, but if it's too big and bulky it can cross the line to "gaudy" pretty quickly. 

This tutorial aims to make the smallest possible NeoPixel module or insert for your project. We've worked to make it super small, at around 1/2" thick and about 2" across.

This tiny package still contains all the niceties:

  • 7-12 addressable NeoPixel lights
  • A compact on/off switch
  • A rechargeable battery with 4+ hours of battery life
  • Onboard USB charging capability

We're using an ItsyBitsy M0 microcontroller, and we've included an easy-to-customize code sample as well.


Electronics Build

The physical build is the tricky party with this project.

This is an intermediate project that requires some tight soldering and careful measuring and cutting. You'll need to work small, and working small can be a challenge. But it's all through-hole soldering -- nothing fancy -- so it's definitely doable with a good soldering iron and a little patience.


We've provided CircuitPython code for this project. The code is pretty straightforward and easy to customize with a few keystrokes.

Price Point

We've tried to keep this project fairly inexpensive so it's easy to fit into your cosplay budget. With a NeoPixel jewel, the cost of this project is around $25-$30 including everything you need.

Parts Needed

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NeoPixel Choices

For my necklace, I'm using a NeoPixel Jewel with 7 pixels. This project would also work well with a 12 or 16 pixel NeoPixel ring if you want more lights.

And in case you're wanting to pack in as many lights as possible, here's a tip: the NeoPixel jewel fits perfectly inside the 16 pixel ring! So you can pack in 22 dense little lights within the 2 inch radius, if that's what your project calls for.

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Round and round and round they go! 16 ultra bright smart LED NeoPixels are arranged in a circle with 1.75" (44.5mm) outer diameter. The rings are 'chainable' - connect the...
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This guide was first published on Sep 16, 2020. It was last updated on Sep 16, 2020.

This page (Overview) was last updated on Nov 27, 2021.

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