How Did the Duck Hunt Gun Work?

If you’re a geek of a certain age, a good portion of your childhood probably revolved around
sitting too close to the TV, clutching a plastic safety cone-colored hand gun and blasting
waterfowl out of a pixilated sky in Duck Hunt (also, trying to blow that dog’s head off when he
laughed at you). The Duck Hunt gun, officially called the Nintendo Entertainment System (NES)
Zapper, seems downright primitive next to the Nintendo’s Wii and Microsoft’s Kinect, but in
the late 80s, it filled plenty of young heads with wonder. How did that thing work?

Annie get your Zapper

The Zapper’s ancestry goes back to the mid 1930s, when the first so-called “light guns” 
appeared after the development of light-sensing vacuum tubes. In the first light gun 
game, Ray-O-Lite (developed in 1936 by Seeburg, a company that made parts and systems 
for jukeboxes), players shot at small moving targets mounted with light sensors using a gun 
that emitted a beam of light. When the beam struck a sensor, the targets – ducks, 
coincidentally – registered the “hit” and a point was scored.

Light guns hit home video game consoles with Shooting Gallery on the Magnavox Odyssey 
in 1972. Because the included shotgun-style light gun was only usable on a Magnavox 
television, the game flopped. The Nintendo Entertainment System (NES) Zapper then fell into 
the hands of American kids in October 1985, when it was released in a bundle with the NES, 
a controller and a few games. Early versions of the peripheral were dark gray, but the color of the 
sci-fi ray gun-inspired Zapper was changed a few years later when a federal regulation required 
that toy and imitation firearms be “blaze orange” (color #12199, to be exact) so they wouldn’t be 
mistaken for the real deal.

While there were a number of Zapper-compatible games released for the NES,
most lived in the shadow of the iconic Duck Hunt, the most recognizable and popular 
Zapper game.

Gone in a Flash

While older light guns like the Ray-O-Lite rifle emitted beams of light, the Zapper and 
many other recent light guns work by receiving light through a photodiode on or in the 
barrel and using that light to figure out where on the TV screen you’re aiming.

When you point at a duck and pull the trigger, the computer in the NES blacks out the screen 
and the Zapper diode begins reception. Then, the computer flashes a solid white block 
around the targets you’re supposed to be shooting at. The photodiode in the Zapper 
detects the change in light intensity and tells the computer that it’s pointed at a lit target 
block — in others words, you should get a point because you hit a target. In the event of 
multiple targets, a white block is drawn around each potential target one at a time. 
The diode’s reception of light combined with the sequence of the drawing of the targets 
lets the computer know that you hit a target and which one it was. Of course, when you’re 
playing the game, you don’t notice the blackout and the targets flashing because it all 
happens in a fraction of a second.

This target flashing method helped Nintendo overcome a weakness of older light 
gun games: cheaters racking up high scores by pointing the gun at a steady light 
source, like a lamp, and hitting the first target right out of the gate.

If you’re hungry for a more technical depth, check out Nintendo’s 1989 patent on
the Zapper technology.

Source