Console gamepad hack
Perhaps, more info could be added on how to connect analogue joysticks and buttons?
A console gamepad hack is very similar to the keyboard hack and USB gamepad hack. This form of hack is only used when a console such as the Sega Dreamcast is used as base for the cabinet instead of a PC. In this case no emulation is involved and joystick movement and buttonpresses are to be directed straight to the console.
Basically the gamepad is taken apart and the connections from the circuit board to the pad's buttons are rerouted to the arcade controls.
Some console gamepads (such as the Dreamcast) make use of a common ground. This makes hacking (and wiring) easier as only one wire is needed per button and direction, plus one common ground. Other console gamepads (such as the Xbox 360) do not have a common ground, making the process more difficult.
Gamepad hacking is most useful for digital controls (on/off) and not analog. Some methods do exist for hacking analog buttons, but in doing so, makes the switch digital.