This diagram uses the original Gemma but you can also use the Gemma M0 with the exact same wiring!
The GEMMA and battery live on the outside of the collar, and the NeoPixels pierce through the collar to be wired on the inside (hence why GEMMA is mirrored in the diagram). Connect up all pixels power pins to GEMMA's Vout, ground to GND, and the first data input to GEMMA D1. The data out from each pixel is wired to the data in on the next.
This guide was first published on May 07, 2014. It was last
updated on Sep 18, 2018.
This page (Circuit Diagram) was last updated on Sep 29, 2017.
You could easily add five more pixels for a total of ten for a more intensely studded look!