This board came about for two reasons. I wanted to learn about the MIC58x1 shift registers on the electronics side and I liked the challenge of programming a scrolling display with limited resources. In the end I managed to program a number of effects (fade-in, fade-out, scrolling, reveals etc.) and scroll text, using code which will easily map to a display of any size.
Unfortunately the cheap Chinese 8x8 LED matrix that I bought has a ridiculous pinout, hence the spaghetti routing. If I was going to design a larger matrix (or one with multiple colours) I would definitely pay the extra to get a decent module.
I initally made the circuit on a breadboard, to test a few alternative methods of wiring it up. Some basic code was needed to make it run, cue a cute little Pacman style ghost.
Images of the silkscreen and routing are below, along with the finished board.
A number of people helped through the process of designing the board and code. In particular, a thread on ETO discussing the options for driving 64 LEDs with less pins was very useful.
- Download schematic (PDF) - the original design
- Download board (ZIP) - Eagle files
This work is made available under the Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA) license.