We'll attach a female 3-pin connector to our Feather M0 and then attach the male connector to the IN end of a NeoPixel strand or strip. For this project, I'm routing the power for the NeoPixels right through the Feather M0 board instead of powering directly from a battery. This works great for smaller projects or wearables with up to around 75-100 NeoPixels. If you have significantly more pixels in your project, you'll want to wire the power directly to the NeoPixels as shown in the NeoPixel guide.
Solder your female 3-pin connector to the Feather as shown:
If you're using a NeoPixel strand, all you need to do now is plug your Feather into the male connector that comes with the strand and plug in a battery. Your lights should come on in a blue and purple gradient.
If you're using a NeoPixel strip, cut the 2-pin connector off and expose the bare copper pads at the IN end of the strip. Solder the male side of your 3-pin connector onto the strip. It helps to plug the connector into the female side before you solder, so you can be sure you're getting the wires lined up correctly.
Plug in a battery and the LEDs will come on in a blue and purple gradient, if all goes well.
If the lights don't come on, here are a few things to check:
- Did you solder the connector to the IN end of the strip? (arrows on the strip should be pointing away from the Feather M0)
- Did you make sure the connector was lined up correctly? It's easy to solder these on backwards.
- Has the code uploaded correctly? The code for this project is tricky, with lots of libraries to install. If it's just not working, try uploading the strandtest code in Arduino (Examples > NeoPixel Library > Strandtest) making sure to select pin 12. More info about this process can be found here.
- Are you soldered to pin 12? The labels are small! Be sure you're on the correct pin.
Optional Antenna Connector
I've found that for wearable projects being controlled in the same room or in the vicinity of the controller box, the antenna is not needed on this end. The controller box has an antenna for broadcasting and the Feather picks up the signal with no trouble. It works through windows and up to around 100 yards away.
If you want to control your project from further away -- say, change the color of your tent lights from all the way across the Playa -- you'll want to solder the antenna connector onto the back of the Feather M0 and snap on the antenna. The process is the same as what you did when building the NeoTrellis controller box.
Adding Additional NeoPixel Strips
You can add a lot more NeoPixel strips or strands to your project on the other data pins the Feather has available. If you do add more strips, or solder to other pins, note that if you can't use the radio pins (pin 22, 23, and 24) for a NeoPixel data line. Leave those pins alone!
You can see the available pins on the Feather LoRa Pinout here.