If you're new to soldering headers, check out this handy How to Solder Headers guide for some tips.
Place the included headers short side-up into a solderless breadboard. Solder the QT Py face-up on top of the headers.
Pull the QT Py out and sandwich the BFF on the back of the board, with the USB port and battery port facing the same way and the boards back-to-back.Â
Solder the headers in place on the BFF. I find it easiest to tape the QT Py to the table to hold it still for this process.
Trim the pokey headers close to the board so you don't stab yourself in the head with them.
Take a look at your NeoPixel strand. It's got a male connector on one end an a female on the other.
Look closely at the wires and you'll also see that one of the wires is marked -- it has tiny dots / stripes all along the length. This is the power (+5v) wire. It's soldered to the red wire on your connector. The black wire is on the far side and is connected to G, leaving the middle wire (green) as the data wire.Â
NeoPixel strips and strands are directional. There is a data IN end and a data OUT end. The red and black wires could connect at either end, or somewhere in the middle, and the strip will work fine, but that data wire must be connected at IN end or the pixels won't light up.
There's no industry standard for which connector comes on the IN end. Some strands of pixels have male on the IN, some have female. This is kind of annoying, since it means we've got a 50/50 chance of guessing right.Â
My strand's IN end had a male connector. You can test your setup with alligator clips, or just temporarily stick the wires in the appropriate holes in the QT Py loaded with code to see if you get lights. If you don't, try the data wire at the other end.
Cut the connector off. It's easier to solder to the colored wires on the connector than to the LED strip wires, so leave yourself a little space. Strip a little shielding off the wires and use your alligator clips to temporarily connect them to 5v (red), G (black), and A0 (green) on the QT Py. Plug the QT Py in via its USB port (make sure the software's been loaded and pin number updated) and see if the lights come on. If they don't, try the other end.
Trim your stemma connector also, cutting off any fancy ends. Trim the blue wire to get it out of your way.Â
Slip some small pieces of heat shrink over the 3 remaining wires. Solder the red wire to the red / striped wire on your NeoPixel strand, the yellow wire to the middle wire, and the black wire to the remaining wire.Â
Cover all 3 connections with a larger piece of heat shrink to keep them secure.
Troubleshooting
If your lights didn't come on, here are a few things to try:
- Flip the on/off switch on the BFF. Was it just turned off?
- Head back to WLED and check your pinout configuration under LED Preferences. Be sure you've told WLED that we are using pin 19 (yellow wire.. check the pinout)
- Check your wiring! Be sure you soldered to the IN end of the LED strip. These strips can be inconsistent so this is a pretty common problem.
- Try re-uploading the WLED software.Â
- If the lights come on but you can't control them, make sure you're on the correct WiFi network - if you're on a different network you won't see the WLED connection.
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GRB Color Order
Normally when WLED first boots up, the default is a warm yellow light color. But our lights didn't boot up in yellow.. they booted up in green. What gives?
Open the WLED interface (open starcrown.local in a browser window). Choose "solid" as your effect and red as your color from the color picker.Â
My lights are now bright green. If I choose blue, they turn blue, but if I choose red or green they appear to be swapped. Not to fear: these pixels simply have a different Color Order than standard. There's a setting in WLED to fix this.
Head to the LED Preferences tab under Config and scroll to the Hardware Setup section. Find the box for Color Order and change it from GRB (green, red, blue) to RGB (red, green, blue). This will swap red and green so your strip matches the interface.
FYI: This can be a problem when mixing different types of strips or strands. Normally you can solder together any kind of NeoPixels as long as you match the pins and get the data order right, or solder multiple strands or rings on different pins on your QT Py. But if the color order is different on one of the strands, there's no way to tell WLED to treat the different strands differently. Changing this dropdown will affect your whole project, so take that into account when you're doing your planning. You may need an additional controller if you want to add a different type of lights.
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