This sign was for our very NYC friends Jon and Cassy as a wedding gift (we had been talking about it for years). There were some trade offs made to get this completed in time for the wedding and traveling between states. The main issue being the sign was split into 3 sections so it could be shipped easier. Also given previous issues with through hole Neopixels, the design allowed for each to have a local capacitor. This was left unpopulated in the final production since it appeared not to be necessary when running at our preferred color and brightness.
The sign is controlled with an Electric Imp in an April board running at 3.3 volts using diodes to boost the signal. The board supports a button to start the lights, stop them, and then a potentiometer for setting the brightness. Given the Electric Imp, there is also a simple web interface to start and stop the lights as well as have them come on daily at a set time.
This was my first PCBs created in KiCad without a schematic. Instead, I wrote a python script using SKIDL to create a netlist of the 179 LEDs and capacitors (plus a few other components). I did this for each of the three sections ("coc", "kta", and "ils"). The netlist was then imported to KiCad and the LEDs manually placed in the PCB layout editor. The position should match closely to the layout of the actual Junior's sign, however the daisy chain order allowed each letter to start on the outside edge, then move to the inner sections. This choice made it easier to code patterns.
The APA-106 kicad foot-print file was from https://blog.crox.net/archives/102-APA106-KiCad-library-including-APA-106-F8-footprint-and-3D-model.html