We'll stack the two NeoPixel rings with the smaller ring on top, and nestle the battery inside the larger ring.  The gemma will sit on the back of the assembly, so the on/off switch, USB port and battery port are accessible.  

Wiring Connections

The Assembly page will show step-by-step wiring. Here is a table of the connections that will be made:

Gemma Gnd

Neopixel 16 G

Neopixel 12 G

Gemma Vout

Neopixel 16 5v

Neopixel 12 5v

Gemma D1

Neopixel 16 IN

Neopixel 16 OUT

Neopixel 12 IN

Gemma D0

back of metal pendant

For the capacitive touch pad to work when it's connected to your pendant, you'll need to be sure to use a pendant that conducts electricity.  Use your multimeter to test and be sure your pendant is conductive.

If your pendant doesn't conduct electricity you can still make this work.  Instead of touching the face of the necklace to change colors, you'll just need to flip it over and touch the gemma's capacitive touch pad directly.

This guide was first published on Oct 11, 2018. It was last updated on May 17, 2024.

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

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