After letting the controller circuit sit in the breadboard for months I finally designed and etched a few circuit boards to put this prototype together. Everything worked out great, I don't think there's anything I would have done differently.
Circuit Board Features
- Shift registers are on separate boards that can be daisy chained together to increase the size of the display.
- Controller board has it's own power regulator so this can be run by any power source that provides 7v-30v (9v battery or 12v bench supply both work just fine for me).
- 6 pin ISP header included so the microcontroller can be reprogrammed without removing it from the board.
- 4-pin header available for future use of the I2C bus. This could be used for an eeprom to store more messages or even to make this a slave device controlled by another microcontroller (RSS ticker anyone?)
- 3 momentary push buttons are included in the design. I may tweak the firmware in the future to include the use of these buttons.
Give me plexiglass, angle brackets, 6x32 machine screws, nuts, and washers, as well as a tap set to thread holes and I can create anything.