The board plugs directly into your USB battery—super cool. I added a long ribbon cable so the battery and board could live in my pocket or a hat while the arrow is on my head. Then I added a JST connector so I can unplug everything easily.

The light strand already has a JST connector on the “out” end, which I planned to use—but it turns out these lights are directional. You have to plug into the in end, or they won’t light up. I accidentally plugged into the out end, so I had to cut the connector off and reattach it to the in end, making sure the wire orientation was correct. After that, the lights came on!

Pro tip: it’s hard to tell which end is “in” and which is “out.” For this strand, the male connector was on the in end, so if I had followed that clue from the beginning, I would’ve saved some time.

Check out the video at the beginning of this guide for a full build walk-through.