Measure the Strip

To start I'll measure the length LED strip required to fit over each ear.

I cut two Neon strips that measured in at 310mm each.

If you choose to use regular NeoPixel strip, the size will measure in at about 280mm.

Use scissors to cut between the pads as shown in the pictures.

Expose Pads

I removed about 17mm of sheathing from the strip so we can fit the strip into slits to be cut on the hat. 

Prep the Hat

I used Adafruit ceramic blades to cut four slits on each side of both ears.

It only needs to be the width of the strip, which happens to be the same width as the ears. 


Fit Strips into Slits

Take note of the arrow directions of the LED strips.

Fit the ends of the strips into the slits and make sure the arrows all go in the correct direction.

Solder Strip Wires

At this point, I proceeded to tin and solder the wires to each side of the first strip.

I measured and cut a silicone ribbon cable to connect the Gemma to the first strip, about 90mm long.

The second strip will connect to the first with a 160mm long wire.


The second strip will get soldered once it is fitted on the ears.

Solder Tilt Switch

Use a small amount of solder to tin the GND and A0 pads on the Gemma.

To fit the tilt switch over the GND and A0, I used pliers to gently bend the two pins apart so they have enough distance to reach the pads.


Thread and Strip Wires

I'll first thread the wires that will connect the Gemma to the first strip.

Pass the wires through the slit and then route the wires into the ear through the rivet eyelets. 

Pass the wires through until the LED strip in taught around the ear.

Solder the Gemma

I used a third helping hand to hold the Gemma while soldering the LED strip connections.

I'll have to share the GND pad, so we can carefully tin the opposite side of the pad to connect the LED strip.

JST Slide Switch

I used a 2-pin JST Extension cable so we can easily disconnect the battery. Measure a cut the cable to 240mm.

To power the circuit on and off, you’ll need to build a slide switch adapter.

I then measured and cut the JST Extension wire at about 60mm from the female connector to solder a slide switch in line with the voltage wire.


Heat Shrink

I used heat shrink tubing to insulate the two pins on the slide switch connections and one the ground wire.

Arrange Board and LiPo Take note of the orientation of the tilt switch. I arranged it so the ball is tilted away from the base. If we don't angle it away from the base, the firework animation will keep triggering.

Mount board

Next I'll test out the circuit to make sure the tilt switch tiggers correctly.

I used a piece of black duck tape to match the color of the ears.

Take note of the tilt switch orientation and then apply a strip of duck tape over the Gemma and tilt switch. 

I placed the Gemma with the USB port on the edge of the tape to allow a USB cable to easily plug in for reprogramming.

Apply pressure on the tape edges to adhere it to the ear.

Mount the Battery

Place the Slide switch on the edge of the duck tape to have easy access to it.

I carefully placed the battery close the to slide switch and then oriented the switch close to the edge on the ear. This way I can easily turn the circuit on and off.

Glue Strips

Now we can finally start to glue down the LED strips to the ears. 

Double check the circuit still functions properly.

I used Dap 00694 Silicone Rubber Sealant to adhere the strips to the ears. Use small binder clips to hold each glued section. 

Allow the glue to dry for about 24 hours.


Test the circuit by shaking to active animations. You can adjust the tilt switch if needed.

Test that the strip is properly glued down. I had to go back and reapply additional drops of glue to sections. The most important parts to check are the sections were the the strips are close the hat slits.


This guide was first published on Sep 04, 2019. It was last updated on Sep 04, 2019.

This page (Assemble) was last updated on Sep 03, 2019.

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