In essence, the Digi-Comp I contained three mechanical flip-flops, providing an ability to connect them together in a programmable way using thin vertical wires that are either pushed, or blocked from moving, by a number of cylindrical pegs. The whole arrangement was ‘clocked’ by moving a lever back and forth. Different configurations of these cylinders caused the Digi-Comp to compute different boolean logic operations. With a three binary digit (3-bit) readout of the state of the flip-flops, it could be programmed to demonstrate binary logic, to perform various operations such as addition and subtraction, and to play some simple logic games such as Nim.
Original Manual [PDF]: https://content.instructables.com/ORIG/F0M/LE8X/K1UYXD8T/F0MLE8XK1UYXD8T.pdf
3D printable version, another example: https://www.thingiverse.com/thing:1477209
We discuss vintage computers, retro computers, and homemade computers.
Perhaps things will become quite dystopic and Intel, AMD & Microsoft won’t be around. Perhaps necessary operating systems will be disallowed for those who engage in wrong-think. Perhaps you desire your own computer platform. Or perhaps you just like old computers.