NeoPixel Strip is made of a flex PCB material that’s meant to curve around surfaces, but it’s not designed to bend laterally. On the original Firewalkers, the bend at the toe was vulnerable to breakage. They would break after a few times of wearing them, so we wanted to provide a way to mitigate that problem— the solution we came up with is to replace the bendiest parts of the strip with a homemade strip constructed of individual pixels and stranded wire, with extra slack for lateral bending. The result is much more labor-intensive than the original, so be warned! It requires delicate soldering of close-together parts and may not be suitable for beginners! You can always glue the strips on as in the original, then upgrade to this new method once the strip breaks…
Wrap your NeoPixel strip around the sole of your shoe to determine the appropriate length, then cut it to size.
Preferably with your shoe on and laced up, bend the shoe at the toe and mark the bendiest parts— we’ll be creating a more flexible section of NeoPixel strip to cover these areas. Hold the NeoPixel strip to the shoe sole again to see where your marks intersect with the strip, and mark down the pixel numbers for the sections to be replaced. For our mens’ size 10.5 sneakers, these were pixels 19-23 and 35-39. Also note how many pixels make up the toe section (35-23=12 pixels around the toe).
Remove the NeoPixels from their sheathing and set the sheathing aside for later. Being sure to start with the input end of your NeoPixel strip, count to the locations of the breaks and cut the strip into three pieces— you’ll have extra strip at the end because the individual pixels will take their place. Solder a piece of 26 gauge to the center data line by tinning the pad and the wire, then reheating the solder to join the two.
Trim and strip the wire and solder it to the input pad of an individual NeoPixel.
Continue soldering data output to data input lines down the chain until you’ve attached as many pixels as you like and have noted earlier (we found 4 or 5 to be a good amount), then chain up to the input of the toe section of the strip. Repeat this process at the end of the toe-section piece of NeoPixel strip.
With all the data lines connected, now it’s time to wire up power and ground. Use 30 gauge wire for this, and make sure there is ample slack in these wires (they should bow out a bit from the strip), as this is what provides the lateral bending ability. If these wires are too short they WILL break when you bend the shoe at the toe! Tweezers really help get this job done.
Now the shoe can bend without fatiguing the flex PCB. Solder longer-than-nessessary wires to the input end of the strip and wire them up with alligator clips to GEMMA and run the strandtest NeoPixel example to ensure that your new custom strip is working. While it’s on, bend it around a bit to see if you have any precarious connections. Inspect the back of your circuit and trim any stray strands or areas that could short out because of a long wire or blob of solder. Attention to detail at this step is critical, or your shoes will break sooner than you’d like!
Cut the sheathing down the back to fit the strip back inside.