A discussion came up with some guests over shabbos. One asked if one could use an overhead projector on Shabbos if it was turned on from before, i.e. could one put a new plastic sheet on it or not? In theory, it should be the same with old school slides. Any ideas?
what would you need a projector for if you cannot play anything? is this a slide projector, tv projector?
the quick answer is no, you cannot 'use' it, since you are not allowed to play with the tv or computer, and an overhead projector is not slide projector.
hope that helps