I never got around to making a proper video about the construction and installation, but I do have this demo of one of the applications I wrote for it:
https://www.youtube.com/watch?v=gSq8dYBHVBQ
I should do a full write-up so I can submit it to HN. Code's on GitHub anyway. https://github.com/masto/LED-Marquee
So one microcontroller with one output pin available is all you need. Since there is no clock signal, timing needs to quite tight.
To find more information you can google WS2812 or Neopixel. Libraries to use the protocol exists for most microcontrollers.
An ESP32 module is a good choice because it costs $2-3, includes wifi and BT, antenna or UF-L plug, and is pre-certified.
With hardware I meant the LEDs/LED matrix. What kind of LEDs did you use and how much did it cost you is what I wanted to know...
They come in various form factors including fairy lights, strips and matrixes.
They are very easy to work with, and there are good libraries or open source platforms (eg wled) to run them.
https://www.amazon.com/gp/product/B09CTQ37DB (I got the 16x16 for $16). Another <$10 for the ESP32. A soldering iron ($40 for a pinecil), $verylittle for solder and hook up wire. In my case, a 3D printer ($500) plus filament ($20), and some design software ($500/year, because Fusion 360 expensive).
They practically give ESP32s away with an oil change, so you could call it done at that point, but I chose to use a QuinLED Dig-Quad (https://quinled.info/pre-assembled-quinled-dig-quad/) to make it easy to wire up and mount on the wall. That cost me about $60 shipped. And I added a MEAN WELL LRS-100-5 power supply for $20.
Finally for the laser-cut frames, I burned up about $30 of wood, and there's some minimal amount of 3D printer filament as well. Along with the incidental things like having to buy a spool of 3-conductor cable, connectors, etc.
So all together I'd guess it was around $300. A completely no-frills version could be maybe half that.