Cut the male end off the USB power switch. Inside you'll find four tiny wires that are color coded. Red is your power wire (5v) and black is Ground (G). The other two are data wires.
Note: some USB switches are charge-only, in which case you'll only find a red and black wire in there. This will still work.
Strip some shielding off the outer wire, then also off the tiny inner wires. Do a 3-way splice to connect the power and ground wires on the JST connector to both of the corresponding red and black wires in the USB cable.
Reconnect the two data wires to each other, white to white and green to green. We're not splicing anything in here, just reconnecting them back the way they were.
We're mainly using this USB cable for power, so we don't technically NEED those two data wires to be connected, but if they are there, then we can reprogram our Feather through the connected USB cable instead of having to dig it out of the coat lining to plug it in.
Why do it this way instead of just soldering the JST connector wires to the Feather's BAT and G pins?
It can be problematic to power all those lights by pulling the power through the microcontroller. If too much current goes through the board -- like if your lights get set to full white at full brightness -- it can be damaged. Wiring the project so the power goes directly to the lights instead of passing through the board is a safer option when you're using more than 30-50 lights.
Power the Feather by plugging in the USB C cable and a battery.
Plug the female side of the JST connector into the male connector attached to the Feather. Grab 3 alligator clips and attach one to each of the leads on the connector.
Strip the shielding from all 3 wires on the IN end of your light strand. These lights are generally not marked in any way, and different sources / lots may have a different wire order.
Look closely: one of the wires may have a reddish/copper coiled wire inside. This is the +5v wire. Data is usually the middle wire, and G is the remaining wire -- but don't trust that your lights are the same as my lights. Test with the alligator clips.
If you can't get the lights to light up at all, you may be connecting to the OUT end instead of the IN end. Try flipping the strip around.
Also, double check that you've set up the correct GPIO pin in LED Settings in WLED - the lights won't come on if you've soldered to pin 12 and set up the software on pin 13.
Solder your connector to the light strand, adding in some more lead wire if needed so the light strand reaches its starting point while the Feather is in the pocket.
Cover the connections with a piece of large heat shrink - mine is clear, so a little hard to see in the photo. Fill the heat shrink with hot glue and then use a heat gun to shrink it down. This will waterproof and strengthen your connection and make it a lot less likely to break -- very important for wearables!
Testing
Once your lights have come on, open a browser and go to your project in WLED. If you gave it a name in the WLED settings, you can get there by typing that into your location bar followed by ".local" -- mine can be reached by going to http://envested.local.
Try changing the color and choosing an effect, and make sure your whole strand lights up and responds.
Troubleshooting
If your lights don't come on or you can't connect to them, here are some things to try:
- Be sure you are using a device that is on the same WiFi network you used in WLED setup
- Check to be sure that the GPIO pin in software setup matches the pin you soldered the data connection to.
- Is your switch turned off? Flip it to see if that's the problem.
- Try reloading the WLED software onto the Feather.
Sealing & Strengthening
Once everything is working, take some time to make it last. Wearables get jostled, wiggled, spilled on, folded, sat upon, and otherwise manhandled all the time, and they almost always seem to break on the very first day of the festival.
Here are a few things that will really help with the longevity of your project.
1. Slide a piece of 1" heat shrink over the Feather to protect it and keep the Data wire from wiggling loose.
2. Use the heat-shrink-and-hot-glue method over all your wire connections to pot the connections in glue and keep them safe. The solder joints are the weakest point of the build and the thing most likely to break.
3. Add zip-ties to any wires that seem to want to pull or flex. Pull gently on all the wires and make sure the strain is taken by zip ties or heat shrink rather than on delicate solder connections.
Page last edited August 02, 2024
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