Some people like to play game console games, especially ports of arcade games, with original arcade controls. Others like to emulate classic games on a PC using software such as MAME. You can buy an expensive arcade style controller, or you can create your own.
An arcade control panel has several switches, generally normally-open
microswitches. A joystick has four switches, one for Up, Down, Left,
and Right, and each button has a switch. Generally, an arcade board
will see a separate pair of wires for each button.
A console controller, on the other hand, uses much cheaper switches
made of a conductive pad under a rubber membrane under each button.
It touches contact points on the normally-open circuit below and
closes the circuit, which causes the encoder to register a button
press. In addition, console controllers typically have an encoder
that turns the parallel stream from its buttons into a serial stream
that can be transmitted over a thinner cable. (The Atari 2600 controller doesn't have an encoder; instead, it uses a simple common-ground make/break system.)
Here's how to modify an NES controller to act as an encoder for
standard arcade controls:
- Disconnect the controller from the Control Deck and open the controller.
- Remove the buttons and their rubber pads.
- Scratch off enough material from each contact point to reveal two separate bits of exposed copper.
- Solder a wire to each bit of exposed copper. Take care not to short the circuit with solder.
- Connect the Start, B, and A wire pairs to your panel's buttons.
- Connect the pairs from the joypad to your panel's 8-way joystick.
- Connect the pair from Select to an additional button, or to a coin mech if your game supports it. (MAME does, some "arcade classics" series games do, and some homebrew console games do.)
- Mount the circuit board under your arcade control panel.
- Re-connect the controller to the console.
Make step 5 longer for newer consoles' controllers such as Microsoft's Sidewinder Game Pad or Sony's original PlayStation controller. Speaking of PlayStation, it's straightforward to make an encoder with 28 independent switches: start with two PS1 digital controllers, mod them as described above, and connect them to an EMS USB2 adapter (http://secure.fragism.com/store/product_info.php/products_id/44).
TheBooBooKitty has found aftermarket game controllers easier to modify than controllers made by the console maker.
If you play PC ports of arcade games, or you use MAME, and you don't want to tear up a Sidewinder, you may want to check out Creating an encoder out of a keyboard as well.