Back in September 2011, Dangerous Prototypes started a competition for designs in 7400/4000 series logic.
I had a project in mind: the Nottingham Hackspace “days accident free” counter. Conceptually simple, it would replace the “manual” one we had with a 12″ high three-digit seven segment display that would automatically count up every day. There would be a big red reset button, probably with flashing lights and alarms when you hit it.
Well, the deadline for the competition came and went with no sign of the project being anywhere near complete. Nonetheless, I kept at it and eventually finished, only 7-and-a-bit months late. Interestingly, someone got a runner-up prize with a very similar circuit.
The basic design is a wooden box with a plastic cover, with masked out segments. The electronics has a mains clocked counter/divider circuit reducing the 50Hz input to a 1-per-day output
The next post explores the electronics to count once-per-day.
The post after that looks at the construction of the enclosure and the digits themselves.
You may now stare in awe at the days-accident-free counter in all its glory:
That guy in the picture? Not me.