Mermaid LED Hair

I’ve wanted to make a mermaid hair accessory since Dianna Cowern and I met in 2018. This is her idea, but she’s incapacitated by long COVID. So, I’m making this project with my hair and makeup artist, Hinano Leung, and sending our love to Dianna in spirit.

You can find everything I used to make this project below.

• Fixed-address tiny pixels
• Seeed Xiao RP2040 microcontroller board
• 1 meter USB cable
• USB power bank (battery)
• Soldering tools and supplies
• Sanding pad or nail file
• 3D printer and translucent filament (optional)

Note that I’m using tiny addressable LED pixels, but you could also use regular fairy lights as an alternative if you want a similar look without as much work. 

Here's the full video to go along with this project! Watch to the see the full walkthrough of my and Hinano's process.

These wires are thin but solid, so they stay where you put them when bent and shaped. I had a really fun time sculpting two hair pieces from these strands, one for Hinano and one for me. For some of them, I clustered a few pixels together to make a larger shape. On others, I twisted each pixel up and branched it out from a central trunk. I did the sculpting with the LEDs turned on, because it’s possible to over-tighten and break the wire connections.

For both, I created a crown shape meant to wrap around the head, with a few hanging tendrils to interact with the rest of the hair or be shaped during styling.

My smart LEDs need a microcontroller to tell them what color to be and when. I’m using the Xiao RP2040 board because it’s super tiny, affordable, and you can code it up with Arduino, like I did, or use Circuit Python if that’s more your jam.

To attach a microcontroller to your own lights, use sandpaper or a nail file to remove the thin coating protecting the wires, and add some heat-shrink. Then, solder the wires to your microcontroller’s power, ground, and a digital output pin.

I wanted the pieces to each feature a different color palette. I ended up modifying the sample rainbow function to only express part of the color wheel– blues and greens for Hinano’s and reds and pinks for mine.

void rainbowGreen(uint8_t wait) {
  uint16_t i, j;

  for(j=40; j<95; j++) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i/3)+j) & 255));
    }
    strip.show();
    delay(wait);
  }
  for(j=95; j>40; j--) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i/3)+j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

void rainbowRed(uint8_t wait) {
  uint16_t i, j;

  for(j=237; j<239; j++) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i/3)+j) & 255));
    }
    strip.show();
    delay(wait);
  }
  for(j=239; j>237; j--) {
    for(i=0; i<strip.numPixels(); i++) {
      strip.setPixelColor(i, Wheel(((i/3)+j) & 255));
    }
    strip.show();
    delay(wait);
  }
}

I’m powering this project with a regular USB backup battery like you’d use to recharge your phone. The cable runs down from the back of the neck to a pocket. This is the safest option because the battery is sealed up inside an enclosure, and not attached directly to the body. It’s not like I haven’t put bare lithium cells in my hair before, wrapped in tape and attached to a hair clip, but I can’t recommend this because if something goes wrong with a lipoly battery, it could heat up and burn you and also potentially catch fire.

Using a backup battery also provides a lot of juice– the LEDs will shine for hours, and of course you can also still use it to charge your phone.

I 3D printed seashell-shaped diffusers using transparent PLA filament. I printed them in two different sizes, and used hot glue to affix them to the LEDs. This is an optional step, but it’s really hard not to use 3D printing for everything once you’ve got the capability.

I also got some perfectly fetching sea-themed hair clips on Amazon. These alone would work just fine.

• Colorful acrylic resin seashell clips
• Gold and pearl starfish clips
• Silver starfish bobby pins

Hinano did my hair in a braided half-updo with some nautical curls. She started by applying a heat protectant, which acts as a sort of primer- It protects my hair from damage from hot tools, like the curling iron, and Hinano says it helps the curls stay longer, too. Another tip for creating curls stay longer is to heat the entire section of hair, by running it through the curling iron, before curling it.

After curling my hair, Hinano created braided sections on each side, along where the crown of the headpiece would sit. To do this, she made a part in my hair that aligned roughly with the edge of my eyeball, and another at my temple. The section of hair should be about 1 inch wide, which is about the distance to the edge of your ear. Since we were going for a looser, beach-inspired look, we left the front pieces loose on either side of my face, and clipped them to keep them out of the way during braiding.

After braiding those sections she twisted them into a bun, pulling the curled ends out to create a decorate flourish. She also added some thinner accent braids throughout, some of which were my hair, and others were extensions.

Hinano hid the microcontroller behind some hair at the base of the skull, and the USB cable can come down over the shoulder or down the back of the shirt.

She used regular bobby pins as well as U-shaped pins to attach the wire structure. Like when I was sculpting the wire piece, we left the LEDs on during this stage to make sure we didn’t damage any of the connections.

Once Hinano finished my hair, I did hers.

To complete the look, Hinano showed me an easy and effective technique for making shiny fish scale makeup.

I'm really happy with the final look! Overall there’s a lot of bang for your buck with this project, and it’s sure to impress at your next music festival, mermaid parade, quinceañera, or bat mitzvah. If you do make your own, please share in the comments– I love seeing what you make!

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