Inspire by Adafruit Mystical Hood tutorial, an Adafruit Gemma M0, NeoPixels, a big hand button and some Circuit Python.
Update the Bootloader and then Circuit Python from: https://circuitpython.org/board/gemma_m0/ (Double click to enter into bootloader)
Get the required libraries (neopixel) from the master circuit python library (copy out of the /lib folder): https://circuitpython.org/libraries (reference: https://circuitpython.readthedocs.io/en/latest/docs/troubleshooting.html#valueerror-incompatible-mpy-file)
Serial Console connection refernce: https://learn.adafruit.com/welcome-to-circuitpython/advanced-serial-console-on-windows
Onboard LED reference: https://learn.adafruit.com/adafruit-gemma-m0/troubleshooting
The button allows me to fade from red to blue and back again. The code isn't terribly efficient, but it serves.
Wiring reference:
11 = Vout (brown to glasses)
9 = D1 (purple to glasses)
7/6 = Ground (grey to glasses, black to switch)
1 = D2 (white to switch)