system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How did the Zapper for old NES systems know where you were aiming on the screen when playing Duck Hunt on those old TVs?

Seems like tech ahead of it's time to me.
gpt
It’s actually a pretty cool thing of engineering.

The zapper itself contained a light sensor at the tip. When you pressed the trigger the next frame of the TV would become all black. The frame after that would be mostly black except for a white box in the hit box of the target. If the gun detected light during this moment, it sent a signal to the NES which meant it was a hit. If you didn’t aim at the right place on the screen, then the light sensor wouldn’t have detected light well enough. Using a lens you can get it’s “pointing accuracy” to be a little better as well.