Help with Kodak Carousel S-AV 2000 Slide Projector

While you are at it, get two relays and do the reverse button hijack also.

@UKHeliBob no doubt means that the Arduino can supply a signal to a circuit that will operate the relays(s).

Many Arduino relay modules exist, they are cheap and easy to use, viz:

Or make your own with a cheap relay and a few parts.

HTH

a7