Optoma Ultra short throw
Ultra short throw projectors have a fixed lens and mirror so you can create large projection surfaces very close to the screen. Ideal for interactive applications. The projector hangs a very short distance above the screen (50m max) and a reasonable screen size is obtained. The versions with usti are the interactive versions, a camera and pen set are included. Connecting this projector with a USB cable turns the projection surface into an interactive board.
This has two major advantages. First, no one will walk through the image because the projector is placed at such a short distance. So it is ideal for meeting rooms or in classrooms. Second, there are also multiple projection options.