

How the Nintendo Duck Hunt Gun Worked - d0ugie
http://www.howtogeek.com/181303/htg-explains-how-the-nintendo-zapper-worked-and-why-it-doesnt-work-on-new-tvs/

======
d0ugie
Note that this was first released in April 21, 1984.

Alternative source:
[http://en.wikipedia.org/wiki/NES_Zapper#Technical_details](http://en.wikipedia.org/wiki/NES_Zapper#Technical_details)

> When the trigger on the Zapper is pressed, the game causes the entire screen
> to become black for one frame. Then, on the next frame, the target area is
> drawn in all white as the rest of the screen remains black. The Zapper
> detects this change from low light to bright light, as well as the duration
> of the "flash", as the different targets on screen (if multiple targets are
> on screen) will flash for different durations. This is how the game knows
> which target has been hit. After all target areas have been illuminated, the
> game returns to drawing graphics as usual. The whole process is almost
> imperceptible to the human eye, although one can notice a slight "flashing"
> of the image. Although the Zapper just detects light, it can only be used on
> CRT displays. It will not work on LCDs, plasma displays or other flat panel
> displays due to display lag. This darkness/brightness sequence prevents the
> possible issue caused by pointing the Zapper right next to or into a light
> bulb. Some people believe that this way it is possible to cheat and get a
> perfect hit score, probably misled by other older light guns which didn't
> use this method.

