For Mark 1, I started with an old laptop running DOS to generate the pulse stream and used the parallel ports as the interface with the MS Windows computer. I used Euphoria, an interpreted language based on ‘C’, to write the pulse generation program as Basic proved too slow. Two pins from the DOS computer’s parallel port were used to connect the pulse streams to the cam and wind stepper motor drivers. A closed loop protocol was used between the DOS computer and MS Windows computer.
For the Mark 2, I developed a pulse stream generator unit using 555 timer integrated circuits and a slotted optical vane switch to detect when the cam had rotated 360°. Photograph 27. The MS Windows computer still controlled when pulse streams were needed.