Poocuzzi is a 4 player game about secretly pooping in a hot tub and blaming it on your friends. Every player must poo before the time runs out or face a stiff penalty. One must poop by carefully letting go off a special poo "key"-- for the ultimate experience, map that key to a custom butt pad!
I used an old Atari 2600 joystick (with a USB adapter to get it to talk to my computer) but you could do this with any simple, hackable game controller.
The idea is trigger the "down" action on the joystick by releasing pressure on a special butt sensor. To connect the butt sensor to the joystick I just used a simple mono audio cable. In order to wire it into the joystick, I drilled a hole in the side of it and added a basic audio jack.
Crack open the joystick and you'll see something like this. I'm working backwards since I've used up all my joysticks so some of the wires on the circuit board have already been disconnected. You can see how the buttons on the board map to the wires by following the silver connections.
Take a look and see how the "buttons" underneath the joystick map to the actual board.
Since you only use the LEFT and RIGHT directions for movement in the game, I disconnected the up and down wires from the circuit board. Pressing DOWN in the game should be mapped to the butt pad, so find the appropriate button, follow the silver on the board to the correct wire.
Solder one long wire to that wire (it's blue on my joystick). Solder another long wire to the ground (black on mine).
I wanted my butt pad to plug into the joystick through a mono cable so I soldered the two wires to the mono jack I installed earlier.
Here's the butt pad itself. I took two PCBs and dropped a bunch of solder all over them. That way, when they touch each other, they complete the circuit. You could probably think of a better way of doing it! The two long wires from the previous step should connect to each side. Keep them from touching with a foam doughnut. I ripped my foam out of an old Dance Dance Revolution pad.
Sew up the sides of the boards to keep them together and then protect it with some tape.
Finally, sew an old smelly sock on there!