Cut 4 pieces of header with 3 pins each. Slot them into a solderless breadboard so that the NeoPixel BFF fits on top, leaving the middle hole open on both sides.
Solder the pins in place with the LEDs facing upwards. If it's your first time soldering headers, check out our How to Solder Headers guide to get started.
Tin the + and - pads on the NeoPixel BFF and solder two long-ish (8" or so) solid core wires. I'm using a red wire on the + pad and a black wire on -.
Bend the wires carefully around over the top of the board and thread them through the holes we left in the headers. Flip the board over and solder the QT Py on. The boards go back-to-back with the USB port facing the top of the NeoPixel BFF (the same end the wires are soldered to).
Twist the wires together over the QT Py, being careful not to squish the Boot button. We'll build the structure of the cufflink out of these wires since they're pretty stiff and easy to work with.
Make a stem of about 1/2"-3/4" and then twist the wires around the JST connector switch to hold it in place. Watch the assembly video on the first page of this guide for more details on how I did the wire wrapping.
Trim the two wires to length and solder them into the JST connector. The red wire goes to SW and the black wire can go to either of the G pins.
The QT Py defaults to sending NeoPixel data on pin A3. However, we can't use A3 since we skipped that pin on the header to make room for our wire to go through. No problem: it's easy to change the pin on the NeoPixel BFF.
Use a sharp knife to cut through the copper trace on the A3 pin pad to disable it. Then, make a solder bridge to connect the two halves of the A1 pin. This will tell the QT Py to send data on pin A1 instead.
Remember to change this in your code! Most sample projects for the BFF will default to pin A3.
If you've already uploaded your code, it's time to test and make sure everything works. Plug a battery into your JST connector and flip the switch to ON. You should see an animated heart and scrolling text. Hooray!
Trim down any pokey header wires with a pair of flush cutter pliers to streamline your cufflink.
Troubleshooting
If you're not getting hearts and messages, here are some things to try:
- Did you fully cut the trace for pin A3 and fully bridge the solder pads on A1?
- Does your code call for pin A1? If you're using example code for this board from a different source you'll want to update the pin number.
- Check to be sure your solder joints are clean and not bridging anywhere
- Try re-uploading the code, and check the troubleshooting tips on the code page
- Make sure you soldered to the correct pins on the on/off switch
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