This project uses four wired connections even though we really only need three. I did this mainly for consistency so each side of the necklace is two wires. The NeoPixel Jewel features two grounds, so that works great here. I started by securing the GEMMA M0 to panavise jr and then attaching the ground wire. Then, I attached one end of the female JST connector to the ground (GND) pin and the other to voltage out (Vout). Be sure the polarity of the JST connectors are matching.
Here I'm soldering the second wire from the JST cable to the voltage out pin. I made sure to tin the pins with a bit of solder, first. Notice the placement of the wires – This will make it a bit easier to lay out the necklace when mounting the GEMMA M0 to the enclosure.
NeoPixel Data to GEMMA M0
Lastly, we'll hook up the green data wire to pin D2 on the GEMMA M0. I ended up rewiring this so the connections are on are the opposite ends of each other. This allows the wires to feel more like a necklace. I have the GEMMA M0 secured to third helping hands so the connections can be seen more clearly.