Replica of a very old design. Used a 4001 CMOS gate IC and a 7490 counter (which can count 0...5 without an external reset gate).
Press the switch to start.
Several additional diodes are required to start and run the oscillator that would run by itself in a real device. See post "Logic Gate Multivibrator with Frequency Modulation" for an explanation.
In the real device, the dice runs much faster, the power switch is a resistive sensor switch, and all capacitors need vastly bigger values for the right timing. It also has very good randomness, which the simulation cannot reproduce.
