How the Nintendo NES Zapper gun worked (and why it doesn't on today's TVs)

My 10-year-old son Lux is a retro videogame historian who collects and studies 1980s consoles and games with the gravitas of a PhD student working on his thesis. Last year he acquired Nintendo's NES Zapper gun controller from 1984 that was used to play shooting games like Duck Hunt. (Below, a TV commercial for the NES Deluxe Set including the Zapper and R.O.B. The Robotic Operating Buddy.) Unfortunately, the NES Zapper doesn't work with modern LCD televisions. The video above from "Today I Found Out" explains the clever technology behind the NES Zapper gun. And here's a great text explanation from How-To Geek about why it doesn't work on non-CRT screens, something my son already knew but, of course, wanted the Zapper anyway for, er, display purposes:

First, it requires extremely precise timing between the trigger pull on the Zapper and the response on the screen. Even the slightest difference (and we’re talking milliseconds here) between the signal sent to the NES and the signal displayed on the screen can throw it off. The original timing sequence was based on the very dependable response time of a CRT hooked up to the analog NES signal. Whether the old tube TV was big, small, cutting edge or 10 years old, the speed of the signal via the CRT display standard was reliable. By contrast, the latency in modern digital sets is not reliable and is not the same as the old consistent delay in the CRT system. Now, this doesn’t matter in most situations.

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