Abstract: A beam direction sensor for determining the direction of each beam in an array of light beams. The invention basically consists of a screen positioned to intersect the array of beams and a video camera to record the position of the images of the intersections. The screen can be any of a wide variety of screens that produce an image of the beams when illuminated with the beam. These include frosted glass and various diffusers. A preferred screen is a holographic diffusers.