A light gun is a pointing input device that detects light using a photodiode in the gun barrel. When the player of the game pulls the trigger on the gun, the screen is blanked out for a fraction of a second, which allows the photodiode to determine where the gun is pointed. Light guns were most widely used with early console gaming systems such as the NES Zapper light gun, as shown in the picture to the right. Using this gun the player could play games where they were required to point the gun at the screen and shoot targets, such as ducks in the popular Duck Hunt game.
Also see: Input device