Cut a red and a black wire, slightly longer than your horn.

Grab a coin cell battery and test your LED.  Make sure you know which is the anode leg (power) and which is the cathode (ground).

99+ percent of the time, the longer leg is the anode, but occasionally a “trickster” LED with two same-sized legs slips by. No harm in double-checking regardless.

Wind one of your resistor's legs to the anode pin of your LED and solder it in place.  Solder the red wire to the other resistor leg, and then solder your black wire to the cathode leg of the LED.


Test again with your coin cell to make sure the LED is still working.  If it all looks good, slip some heat shrink over the connections to cover them and keep them safe from shorting.

Grab your neopixel ring.  Solder a red wire to 5V, a black wire to G, and a white wire to IN.  

Note: it's easiest to slip the wire in from the neopixel side, then make the solder joint on the back of the ring.


Pull the wires through to the inside of the ring and trim to about 2".

Twist the black wire from the neopixel ring together with the black wire coming from the LED and solder both into the G pin on your Gemma M0.


Solder the red wire from the neopixel ring to the 3V pin on the Gemma, and solder the white wire to pin D1.

Finally, solder the remaining red wire from the LED to pin D0 on the Gemma.

Plug your battery into the Gemma and be sure it's switched on.  If you haven't done so yet, upload the code.  Test to be sure your neopixels come on.


Touch pad A1 with your finger.  The neopixels should go off and the LED should light up.  Yay!

If your touch pad is too sensitive or doesn't seem to do anything, you may need to calibrate the code.  We'll go over that in the next section.

Battery Charger

Cut and solder ONE wire at a time! DO NOT cut through both at once. LiPoly batteries can catch fire if treated incorrectly!

Trim your JST connector to about 2".  Carefully cut the red wire to your LiPoly battery.  Slip on some heat shrink and splice in the red wire from your JST connector.


Repeat with the black wire.  You now have two plugs connected to the battery: one for the Gemma and one for the charger.

This guide was first published on Jan 26, 2018. It was last updated on Jan 26, 2018.

This page (Electronics Assembly) was last updated on Jan 17, 2018.

Text editor powered by tinymce.