REDESIGNED! The original 8x8 display board only hosted the WS2812B LEDs, now it's got a whole system on each board, which can easily run standalone or in large arrays.
I started this whole system design over a year ago, and recently had a epiphany which led to a complete redesign.
This is just the first of several boards of my "system", which will consist of:
* 8x8 LED matrix module, consisting of a simple 8x8 array of WS2812B (or SK6812-RGB or even -RGBW!).
* WiFi interface/control module. Probably ESP8266 based.
* Backup-battery subsystem (2x 12V SLA's = ~24VDC).
The new 8x8 display board now integrated its own PIC micro, plus serial-flash for the playback frame-buffer.
Each of these display modules can be easily daisy-chained using CATx (UTP) cable fitted with standard RJ45 connectors.
Almost no power wiring! The display boards are generally laid out next to each other, touching. Linking the +24V and GND rails is really easy - just use standard "barrier terminal block" jumper straps. They are readily available standard bits (Cinch P/N 141J-1).
Distributed +5V: Rather than one giant (+5V @ 100amps?), each display module has its own 5V SMPS block, capable of accepting the 24VDC external power rail.
The SMPS block is designed to work with 9-24VDC, but to minimize losses in the wiring, it's best to stick with 24VDC.