Stemma Adapter
First, you'll need to make an adapter so you can plug the LED strip into the Feather using the STEMMA QT port.
Cut the 4-pin male connector off the OUT end of your LED strip. If yours doesn't have one, we have them in the shop but they aren't so handily color-coded.
Trim the red wire on your STEMMA QT connector so it's out of your way. This wire carries a 3.3v current and will damage the Feather if you connect it to the 5v DotStar strips.
Strip 1/4" of shielding off the other 3 wires of your STEMMA QT connector and your 4-pin male connector. Match up the colors and solder the wires together: Yellow to yellow, green to blue, and black to black.
Solder the remaining red wire on the JST connector to the USB pin on the Feather.
Cut the male end off your power switch tail and strip the shielding back by about 1/2". Inside, you'll find 4 wires: two data wires, a power, and ground. They should be color-coded: the power wires are red and black and the data wires are colored.
We're going to ignore the data wires since this cable is used for powering our project.
Extend the power wires by splicing on a few inches of red and black wire to the little red and black wires on the switch.
Cover the connection with a big piece of heat shrink.
Solder the red and black power wires at the beginning of your DotStar strip to the power wires on the switch, matching red and black.
Plug the JST connector into your JST/stemma adapter.
We have safely powered our project without pulling all the power we need for the DotStars through the Feather.
Later on in the project, I ended up cutting and re-attaching these power and ground wires so they pass through a hole drilled in the frame. At that time, I also added a second power and ground wire to the far end of the LED matrix to "inject" power at both ends and avoid having the strip dim from the voltage drop that happens when the power flows down a long strip of LEDs. Check the wiring diagram page to see the final wiring layout. For now, you just need a solid power connection to the IN end so you can test each strip as you go.
Plug a USB cable into the other end of your switch and into power. Your light strip should come on in yellow. Did it? Hooray! Time to wire up the rest of the strips.
If it didn't come on, see below for some troubleshooting tips. You really want to get this working before moving forward, since testing is essential for the next portion.
Troubleshooting
If your lights didn't come on, here are a few things to try:
- Reseat the STEMMA QT connector and the JST connector and make sure they're tight.
- Flip your on/off switch. Was it just turned off?
- Check to be sure you've connected to the IN end of the strip. Look for little arrows pointing in the direction of data flow and make sure the arrows are pointing AWAY from the connection you made.
- Head back to WLED and check your pinout configuration under LED Preferences. Be sure the settings here match the screenshot on that page. It's easy to get the numbers crossed.
- If you're getting lights but strange behavior (odd colors or patterns), be sure WLED is configured for APA102 lights -- it defaults to WS2812 (NeoPixels) but we're using DotStars here.
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