Light gun

A light gun is a pointing input device that detects light using a photodiode in the gun barrel. When the player pulls the trigger on the gun, the screen goes blank for a fraction of a second. This brief moment allows the photodiode to determine where the gun is pointed. Light guns were most widely used with early console gaming systems. A good example is the NES Zapper light gun, which is shown in the picture. Using this gun, players could shoot targets displayed on their TV, like ducks in the popular Duck Hunt game.

Hardware terms, Input device