I am on the lookout for an ultra portable projector that i can connect to a microsoft surface tablet via HDMI. I want something as small as possible but that is still perfectly fine for projecting during a presentation and that the whole has to be in darkness for anyone to see anything (i'm not sure at what size point they start to become more of a novelty)

I wondered if anyone had any experience with using any small, portable projectors and could recommend anything?