How did Duck Hunt for the NES know where you were pointing the gun?

Question

How did Duck Hunt for the NES know where you were pointing the gun?

In: 7118

Answer 1

The game doesn’t read the gun, the gun reads the screen. If it sees white, it’s a hit. Anything else, it’s a miss. If you pointed the gun at the edge of the screen or at a bright light, it would always see white, always “hit” the duck, and that’s how you cheated at Duck Hunt.

The Zapper doesn’t work with flatscreen TVs because the screen can’t flash as brightly as a CRT, so there isn’t enough light for the Zapper to “see” the white box.