How did the Duck Hunt gun work?

Just found out today how the gun for Nintendo’s Duck Hunt game used to work.
Though I had always found its workings to be a bit mysterious, I never gave the problem a serious thought and still find the solution quite elegant(because its pretty simple too)
The answer is sort of counter intuitive because being a gun,you’d expect the device to fire or shoot something but the NES Zapper does exactly the opposite!
Here’s the lowdown,
The gun contains a photodiode (a diode which can conduct according to the intensity of light incident upon it)
The detection of the target happens as follows:
When you press the trigger, the controller blanks out the screen (the screen becomes completely Black)
The controller also activates the photodiode.
After this,the controller flashes a white block in the region where the duck originally was.
If you’re pointing in the right direction the photodiode will register a high else its a low and a miss.
(How synonymous ‘low’ and ‘miss’ seem ,though their usage here puts them in completely different domains) .
Of course, all of the above happens in a matter of milliseconds and you hardly see a thing.
Simple but Awesome!
If you want more than the simplistic description above, check out:
[How Did the Duck Hunt Gun Work?] via [MentalFloss]
[The Patent for the Zapper]
====x=====x==== Some humour while on the subject