Are you a teacher on a budget looking for a programmable light-up system your students can use at home and keep for their own projects? Or maybe you want an inexpensive, simple way to incorporate lights and a microcontroller into your wearables permanently.  Here's a quick and easy solution -- perfect for Halloween, cosplay, or just making outfits that really stand out!

This guide will show you how to use a Gemma M0 microcontroller and "fairy lights" -- a strand of one-color LEDs strung along a lovely silver wire that can be bent to hold its shape -- to add lights to wearables and decorations.

Although the Gemma doesn't have the functionality of the Adafruit Circuit Playground Express board (still my favorite board for adding light effects to wearables), it does have a color-changing DotStar LED built in.

And with free, online, beginner-friendly MakeCode Maker (cousin to the version of MakeCode used to program the CPX), you can program the LED strand of lights to blink, dim, and brighten in unison.

Make your light patterns run on a continuous loop, or use the touchpads on the Gemma M0 to control and change the light effects. Add these lights to a hat for Halloween or cosplay, or any wearable that can hold a board and battery pack.

As an intro coding project for kids and other beginners, the drag-and-drop MakeCode programming lets you get creative, fast!

You can use the same technique to connect a strand of lights to a Circuit Playground Express or a BBC Micro:bit, and still control them with MakeCode!


These are the parts you'll need at minimum. The Wire Light LED Strand also comes in warm white, red, green, and blue -- choose your favorite!

Pink polished fingers holding a Adafruit GEMMA M0 - Miniature wearable electronic platform.
The Adafruit Gemma M0 is a super small microcontroller board, with just enough built-in to create many simple projects. It may look small and cute: round, about the...
Lit coil of thin flexible wire with embedded LED 'fairy' lights attached to battery holder
Add sparkle to your project with these lovely silver wire LED strands. These strands are very interesting, they use two silver wires that are coated so they don't short if they...
Angled shot of closed 2 x 2032 coin cell battery holder with on-off switch and JST PH Connector.
This tiny coin cell battery holder is ideal for small portable or wearable projects. It holds two 20mm coin cells (2032 or CR2032 are the most popular size) in series to generate 6V...
Front shot of CR2032 Lithium Coin Cell Battery upright.
A perfect match for our sew-able coin cell holder. This non-rechargeable coin cell is CR2032 sized: 20mm diameter, 3.2mm thick. It...
USB cable - USB A to Micro-B - 3 foot long
This here is your standard A to micro-B USB cable, for USB 1.1 or 2.0. Perfect for connecting a PC to your Metro, Feather, Raspberry Pi or other dev-board or...

Optional Parts

Depending on what you want to do with your programmable fairy lights, you might find some of the following useful:

Front shot of JST-PH Battery Extension Cable.
By popular demand, we now have a handy extension cord for all of our JST PH-terminated battery packs (such as our LiIon/LiPoly and 3xAAA holders). One end has a JST-PH compatible...
Top-down view of 6 pairs of short wire alligator clips.
Connect this to that without soldering using these handy mini alligator clip test leads. Approximately 4.5" overall cables with alligator clip on each end, color coded. You get 12...
Close up angled shot of a LED strip attached and powered by a circuit playground.
You have a Circuit Playground Express, and want to connect some wires to it for adding LEDs or sensors or speakers? You can use our...
Red and black multi-size wire stripplers, closed
These are the finest wire strippers we have used, and if you have to do a lot of wiring, you will agree! They have soft rounded grips - very comfortable to use, and precision ground...
Array of many colorful heatshrink tubes.
Heat shrink is the duct tape of electronics which I guess makes this heat shrink the colorful and exciting duct tape they sell at craft stores.  This heat shrink comes in six...

This guide was first published on Oct 13, 2020. It was last updated on Mar 08, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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