The BeagleBoard sends its output image to a large dispay (such as that made by a projector). A laser pointed at this display is used to determine user input. A usb webcam sends the input image it detects to the BeagleBoard, which then locates extreme intensities of red (laser). It then uses the location of this specific intensity to make selections determined by the users input (pointing the laser). It is basically like using a laser-pointer for a mouse.