After this tedious step, he designed a PCB that hosts an Arduino Nano to accept input, two MCP23017 GPIO expanders to give it enough outputs, and CD4066BE CMOS switches to trigger the connections.

Can also pass NULL to use the default pin assignments (digital pins 0-7 on Adafruit Metro Express or Arduino Zero): Adafruit_NeoPXL8 strip ... Microcontrollers compatible with this code are all 3.3V ...