This was mostly done on the fly, so I don't have a ton of documentation. Letters were made using fusion 360, just an extruded rectangle with the letters cutout, and then printed on an Ender 3 v2 (cut into 2 pieces so it could fit on the bed). I used a pi pico with circuitpython to control these LEDs, https://www.amazon.com/dp/B01CDTEJR0?psc=1&ref=ppx_yo2_dt_b_product_details

I used the adafruit neopixel library to control the LEDs and I had a plastic button sitting around from an old project that can toggle the color.

Circuitpython code is here: https://pastebin.com/Uzkh3Y6K