Overcomplicated trigger in zapper

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krzysiobal
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Overcomplicated trigger in zapper

Post by krzysiobal »

Most (all?) zappers drive $4017.D4 low and when trigger is pressed, it is driven high (on the console side logic levels are opposite).
Cheapest and simplest mechanism is just two pieces of metal touching each other and a spring.
Image

More reliable way i to use regular NC switch (with extra spring if the trigger is quite heavy)
Image

Utimatelly I found this one - switch (using NO pin) and ratchet mechanism.
Image
When not pressed, it drives HIGH. When you pull trigger, it closes the switch in about half way the trigger position, further pressing will cause the ratchet to "jump" and the switch will again become open. And this is the moment that game detects pressing.
But (at least on this model of zapper), this is very unreliable. If you press trigger fast, this mechanism fails to work. What was the main goal of such complication? (the only "advantage" is the extra loud click produced by ratchet returning to start position)
Image

I fixed it by gluing those two red parts permanently together and change pin from NO to NC.
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lidnariq
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Re: Overcomplicated trigger in zapper

Post by lidnariq »

That sounds similar to the actual OEM zapper, where the electrical switch is only pressed when the trigger is half-pulled, and not on the release.

But in the OEM zapper it's been perfectly reliable for me.
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looks identical to an OEM zapper, actually
looks identical to an OEM zapper, actually
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krzysiobal
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Re: Overcomplicated trigger in zapper

Post by krzysiobal »

Oh, wiki says there is 10uf cap on the trigger line, but I can't find anything like that here. Maybe that's the reason.
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Pokun
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Re: Overcomplicated trigger in zapper

Post by Pokun »

Yeah the OEM NES Zapper has always been reliable, mine is still in good condition.

The reason of the mechanism is probably to get both tactile feedback and loud springy noise feedback in order to simulate the double-action revolver mechanism of the Famicom kousenjuu gun despite not having a hammer. When you start pulling the trigger the hammer will start to cock itself until a certain point where it's released (where the is switch no longer actuated) so that games can shoot on the falling edge of the switch.
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