Hi, I'm still going for the option of handmaking the DMD, how many shift registers can I use before the signal degrades, I would use rows of 4 down 128 across or vice versa (32 registers down, 16 across) will the signal degrade? I want to use a seperate arduino for the display, what is the smallest I can use. I would use a serial output from the main CPU to the DMD CPU which would use built in commands to detect, eg. It detects a three so it uses the assigned bitmap.
Will this work,
You're running digital signals and with serial shift registers each one can serve to connect the next one, the signal re-originates at each chip. That's with 4 Arduino pins and lots of data out through SPI to run the whole show.
Power distro will be a concern and that will be different if you multiplex (limited leds can be ON at the same time) vs one-register-pin-to-led (all leds can be ON at once). Multiplexing cuts the number of shift registers required significantly. Charlieplexing can cut the number even more, but the wiring will be a maze in itself. All of those can be run from serial data on a daisy-chained SPI bus at cost of 4 MCU pins.