Bending a printer control board to output POV messages

Confronted with the issue of finding a use for his mounting pile of junk electronics, [Rue] set out to build a persistence of vision device using a hardware state machine. We have a suspicion that his original link may go down if there’s too much traffic so here’s a cached link just in case.

Any board that is MSC-51 or MCS-48 based would have worked for his purposes. This is because the addressing scheme of the hardware makes it an easy hack. The image above shows him cutting off the processor¬†from this board. It was chosen because of a 74HC373; it was a mistake at first but since it’s pin compatible with the 74HC374 that he needed a simple swap did the trick. From there a clock source was added, and the address information necessary to display the message was burned into an EEPROM.

Step twelve of his writeup shows a Morse Code message created by attaching the board to a broomstick and twirling it around in an arc. We took ¬†just a minute to decode the message and believe it’s a shout-out to Hackaday. Nice, thanks for reading [Rue]!

12 thoughts on “Bending a printer control board to output POV messages

  1. Excellent timing, no pun intended! I just happened to find an entire phone system from the mid-80s, and the main box has a TON of ICs like these (7400 logic). How do you guys at HaD do that?!? :)

    1. well carefully remove all the chips, take a sander and sand off all the traces, solder chips back in as desired, and point-to-point wire them into the circuit you want to build. if your lucky the board will have internal power planes, meaning you dont need to rewire power to the ttl chips. carefull of 749x the power pins are in different places than every other chip.

  2. So he’s using… what? from the original board. A driver, and a socket, looks like… strikes me as more hassle to bother with this when he assuredly has a breadboard handy. :S

    1. I have to agree, surely it would be better to simply get some braid or a solder sucker and remove everything of value from the board, then keep some vero/breadboard handy for actual construction? It would certainly be a lot more compact.

      1. I kinda agree, I may have overhacked it, it might have been more of a hack if I’d taken that 8085 compatible controller and redone the firmware on it. BUT it was about re-jigging the board into a hardware state machine. I used one of the driver chips there too dont forget. There are about 1000000 pointless things done to accomplish that task that made no difference cause I really was just having some fun.

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