Wiring Diagram

This project won't work with a 'classic' Gemma because we use the Gemma M0's built-in capacitive touch!

Wiring

Gemma 3V

Neopixel Ring 5V

Gemma A0

Neopixel Ring IN

Gemma G

Neopixel Ring G

LED G (Cathode)

Gemma A2

51 ohm resistor

LED + (Anode)

Gemma A1

Copper Tape

Battery Charger

To add charging capability, splice a second JST connector inline with the battery's wires, and plug in a USB charger.

Why solder NeoPixels to the 3V pad instead of the Vout pad?  

The Gemma M0’s Vout pad could give us 3.7V straight from the battery or 5V from USB, and the NeoPixels are brightest at these higher voltages.  However, we've designed this project to leave the battery plugged in at all times, and even with the Gemma switched off, anything connected to the Vout pad will slowly drain the battery.  Wiring to 3V will fix this problem!

Since we've only got 12 pixels, the 3V pin will give us plenty of power.  Don't use this trick if you're trying to power a whole lot of NeoPixels!  The Gemma’s 3V regulator won't handle a larger strand very well.

This guide was first published on Jan 26, 2018. It was last updated on Sep 21, 2018. This page (Wiring Diagram) was last updated on Jan 26, 2018.