A C-64 RELAY BOARD FOR USE WITH
Robert S. Owen, CET, Ph.D.
The shutter t-scope requires some way to cycle the slides in the projector
and to open the shutters. The computer cannot be connected directly
to these divices; it needs a buffer between the computer and the shutters
(which have their own drivers which accept TTL inputs) and some way to
operate the high-current switch of the slide projector.
Relay board plugs into expansion slot in the back of the C-64 computer.
The relay board uses two gates of a 74244 to run the TTL drivers of
two high-speed shutters, and four gates to run four relays which operate
the forward and backward switches of two slide projectors.
Schematic of the Relay Board
Layout of the PC Board
Double-sided PC Card Foils