Blast from the past. This is an old project that I did in sophomore year of undergrad at Binghamton University for CS 312, a course in fault-tolerant systems.

This is a TTL circuit that illustrates “5 Module Self-Purging Redundancy“.

The 5 switches in the upper-right are simulations of 1-bit computers and the other circuitry is designed to figure out the right answer based on a “vote” and then to determine the faulty “modules” and disconnect them so that they don’t influence the output..

On the left, you’ll see a DIN jack underneath a large capacitor that is fastened on with masking tape. This little jack conveniently accepted a 5 volt power supply which I believe I got from one of my old Atari 8-bit computers (Atari 400 or Atari 800XL).

I wired this baby up with wire wrapping over the course of one very awful spring vacation. “Debugging” this thing was “fun”, as you can probably imagine. I think I almost went crazy from staring at all the little wires.