How does the light gun for a video game work?
How does the light gun for a video game work? Lots of home video games and arcade games use some sort of gun as an input device. You point the gun at the screen and pull the trigger, and if you hit the target on the screen, the target explodes. To create this effect, the gun contains a photodiode (or a phototransistor) in the barrel. The photodiode is able to sense light coming from the screen. The gun also contains a trigger switch. The output of the photodiode and the switch are fed to the computer controlling the game. At the same time, the computer is getting signals from the screen driver electronics. If you have read How Television Works, you know about the horizontal retrace and vertical retrace signals used to align the picture on the screen. The screen driver electronics send pulses to the computer at the start of the horizontal and vertical ret
