This ukulele uses side-lit NeoPixels (90/m) around the inside edge of the body. Side-lit pixels are great for fitting into curves. They're assembled differently than regular NeoPixels, which flex front-to-back with the pixels shining straight out. These pixels shine to the side, so the flex direction of the strip can curve beautifully along the perimeter of the ukulele body. I have 28 pixels per side.
For the neck, I'm using two strips of Skinny Neopixels (144/m). These are going straight and so can lay flat (more or less) with the light facing straight forward. I have 24 pixels in each strip.
The Feather Sense and PropMaker Wing are attached to the battery in a tidy stack and stuck to the inside back of the ukulele with industrial velcro. Our homemade USB extension plugs into the Feather's USB port and threads through to the outside of the body -- this board has onboard battery charging, so we can charge up our battery as well as update the programming via the USB port.
Our on/off switch will also thread through a hole next to the USB port.
Measure your strips to your ukulele, count out your pixels and cut your strips to length. These high-density strips can be tricky to solder to, so I like to use the "sacrificial pixel" method, leaving a full solder pad on each side while sacrificing the pixel in between.
Learn more about how this works in our How To Solder NeoPixels Guide.
There's not a lot of space inside the neck, so I pulled my Skinny strips out of their silicone casing to better fit them inside. I left the side-light strip cases on.
Grab your 3-pin STEMMA connector and solder it to the color-coded wires on the IN end of strip #1 (side-light strip). You can clip off any remaining extra wires.
The next strip in line (#2) is the skinny strip that goes up the neck. Use a 3" piece of ribbon cable to connect it to the side-light strip.
Here's where you need to be extra careful - the pads on the side-light strips are not laid out in the same order as on the skinny strips. I had to put a twist in the wire to get the correct pins connected to the correct pins. Look closely -- you want to match + to +, G to G, and DO (on the side light strip) to DI (on the skinny strip).
Next we'll solder the wires for the u-bend in the pixels up by the headstock.
Cut a short piece of 3-wire ribbon cable -- about an inch long.
Solder the OUT end of one skinny strip (#2 in the diagram above) to the IN end of your second skinny strip (#3), matching the pads - + to +, DI to DO, and G to G. Bend the strips so they lie next to each other as neatly as possible. Put a little hot glue over the solder pads so they're less likely to come apart during assembly.
Solder strip #4 to the OUT end of your second skinny strip to complete the circuit around the ukulele. Don't forget to match the pads with a twist in your ribbon cable.