The larger crystal is big enough to fit the Circuit Playground Express and a small battery inside, making wiring very simple. Just plug in the battery or USB cable and you're done!
For the smaller crystals, it works best to put a single NeoPixel inside, since the Circuit Playground won't fit. You can also string multiple crystals together to make a hanging lamp or glowing crystal cluster. These are wired as follows:
- VOUT to +
- A1 to IN
- GND to -
If you have more than one crystal, wire each OUT pin to IN on the next NeoPixel in the sequence.