I am thinking of trying to build a large led matrix in a way that is both modular and scalable (maybe up to around 100x100, or 500x16).
My thought is to make a single 8x8 module that I can make a few at a time as budget allows. Each module will simply pass its rows and columns through to the adjacent modules. I will use shift registers (595 or similar) on the end modules only to drive the columns and the common cathodes on the rows.
Is there a limit to how many shift registers I can chain in a row, or will they pretty much extend indefinitely? Are there any limits other than the time required to shift out an increasing number of bytes? As the number of columns increases the time to shift out that many bytes increases, so I could imagine needing a heavier microcontroller to shift out larger displays at higher refresh rates. I am not too worried about that. My initial design will use an arduino, but I can move to a heavier 32 bit mcu as I need it.
My main concern is current. If I only am driving one row at a time, does it matter how many rows I have connected to each column? Do I need to adjust my resistor values as the matrix scales up, or add more resistors per column? Does my power supply need to get bigger the more leds I add?