Commodore Plus/4 signals morse code to LEGO plotter

The BASIC program to control the plotter

Entering a word to be plotted in morse code

Photo resistors receive information from black or white areas on the screen

The LEGO morse code plotter.
The engines are powered through relays controlled by the photo resistors.

LDR and relay schematics (click to enlarge)

The engine that does the paper feeding

The pencil lifted and lowered by another engine

The resulting morse code