How does the Duck Hunt gun work?

Question

Often I find myself discussing Duck Hunt. How did the gun work? It's not like it was pointed at the box, it was pointed at the tv. How is it that the duck hunt gun works with any tv, even my tv from the '60s? It's not like they were preparing for duck hunt technology development back then...or were they?

Answer 1

When the trigger was pulled, the game blanked out the screen with a black background for one frame, then, for one additional frame, drew a solid white rectangle around the sprite the user was supposed to be shooting at. The photodiode at the back of the Zapper would detect these changes in intensity and send a signal to the NES to indicate whether it was over a lit pixel or not. A drop followed by a spike in intensity signaled a hit. Multiple sprites were supported by flashing a solid white rectangle around each potential sprite, one per frame.

It is possible to cheat in games by changing the brightness and contrast of the television, or pointing the gun at a bright light. The gun thinks it is pointing at a solid white target and will report a hit. If there are multiple targets, the "hit" target will be the first to be lit with the white square. This is not as consistent with a fluorescent lamp due to the possible differences in timing of the lamp's flicker verses the timing of the television's refresh rate.

Additionally, by using a magnifying glass on the gun, it fools the receptor into thinking that the rectangle is much larger than it actually is, allowing for a shotgun-like effect that will cover the entire screen.

If one desires an extreme mod to improve nintendo zapper "accuracy", shortening the barrel length is a simple (albeit permanent) way to get higher scores more quickly. The forward refracting lense is removed and allows the zapper to scan more area of the screen. However, this is not a recommended practice, for modifications to the zapper are irreversible.

Due to the Zapper's technological limitations, it is not compatible with HDTVs. The "stretching" of the game's picture can cause a time delay of several frames with the picture output by the console so that even well-aimed shots, which would register as "true" on standard televisions, almost always fail as a result of this time latency.

Answer 2

Well the gun fires a "lazer" I guess you could say so when it did it reflected off of the TV and it would know where you shot. From what I know that is how it works as the gun wont work on a projector screen.