3 Speed Turbo Fire Joystick Schematic

[Engeliron]

Hello all, I searched on the forum for rapid fire joystick and found some vague schematics to get what I wanted. I wanted a turbo fire joystick that allowed either normal fire, 5, or 20 times per second firing rate (just like an old NES controller I used to own). Here is the crudely drawn schematic to get that working with a 556 timer,a single pole triple throw switch, 2 FETs, some resistors and capacitors. You could probably get this to work with only 1 FET but I realized that after I got this working and am too lazy to rewire the joystick. Hope this helps.

[Engeliron]

Sorry, I forgot to pencil in that you have to connect pin 14 on 556 timer to VCC (Pin 7 on Atari) as well otherwise chip won't work

[Engeliron]

Revised Schematic

[+Stephen Moss]

Not sure that will actually do anything useful.

Those kinds of circuits save on RSI over repeatedly pressing the button but only work if the software is looking for a push - release - push fire input, even then they only work when in sync with when the system polls the fire input so you may actually miss presses when they get out of sync. However, if the software is only checking for a high or low logic state then they are rather useless as just holding the fire button in will provide the maximum fire rate as it will fire every time the software poll the inputs which by definition is the fastest rate you can fire.

[Engeliron]

You make a good point that most games are just looking for the press of the button. The game Defender needs you to release the fire button in order to fire again. This is the game I used to test if my rapid fire really worked. You're pretty much invincible at 20 times per second fire rate. Otherwise if you keep the button pressed it doesn't fire again.

All that aside I built it for the fun of it and also remembering as a kid using the Quickshot 2 turbo and thought how cool it would be to make my own at the firing rates I wanted.