Use small alligator clips to connect the components together for testing; we’ll solder it up later. The pins on the NeoPixel strip are small, so be sure to double check your connections if your having trouble getting them to light up. It might be easier to solder wires to the NeoPixel strip and then alligator clip to those. The NeoPixel strips digital input connects to pin D1 of the Gemma. The negative connection of the NeoPixel strip goes to the ground pin on the Gemma. The positive power wire of the NeoPixel LED strip connects to the Vout pin of the Gemma (not 3Vo!).
If you have all your connections securely clipped, attach the rechargeable battery to the JST port on the Gemma to power it on. The NeoPixel LEDs won't light up because there's no code loaded on the Gemma yet! Use a USB cable to connect the Gemma to your desktop.
Even though the current “v2” and “M0” versions of Gemma now include an onboard power switch, we’ll be leaving it in the “on” position and adding a separate switch of our own, so the circuit can be easily turned on or off after it’s installed in the 3D-printed case.