Old Arcade Controller to Resurrect

This type of controller can be found at yard sales and online auctions -- they were made for MAME gaming on PCs with PS/2 or sound card joystick ports. Build like tanks, they contain real arcade joysticks and buttons and an obsolete controller interface PCB we'll bypass to modernize it!

This guide shows an X-Arcade Tankstick, but nearly any arcade-style controller should work.

Terminal PiCowbell

Orient your Pico H or Pico WH as shown -- with the Pico USB port above the PiCowbell I2C STEMMA QT port -- and press the header pins into the sockets.

Download Firmware

From the GP2040-CE Downloads page, click the Download button for the Raspberry Pi Pico firmware.

This will save a file named GP2040-CE_0.7.8_Pico.uf2 (or later) to your download location.

Firmware Installation

This page gives detailed instructions on installation, but the basic steps are:

• While holding the BOOTSEL button down, plug the Pico into your computer with a known good data and power USB cable -- this puts the board into BOOTSEL/USB drive mode
• A new removable drive named RPI-RP2 will appear on your computer
• Drag-and-drop the GP2040-CE v0.7.8.uf2 (or later) firmware .uf2 file onto the RPI-RP2 drive and wait for it to copy the file and reboot itself

Web Configurator

Unplug the Pico from your computer's USB cable. Then, you'll use a short wire to jumper Pico pin GP17 to a GND pin (see attached diagram for physical pin locations).

Plug the Pico into your computer's USB cable while pin GP17 is shorted to ground. After a couple of seconds you can remove the wire. This action has caused the Pico's GP2040-CE firmware to launch a web server you can access from your computer's web browser by visiting http://192.168.7.1

Settings

You can now update the controller settings.

Click on the Settings menu item and then switch the Input Mode to PS3/DirectInput then press Save.

You can alternately use this on your Switch, Xbox, or Playstation -- just pick the appropriate Input Mode from the menu.

Reboot

To get the Pico out of configuration mode and into controller mode, click the REBOOT button in the upper right corner of the configuration page. 

This opens a reboot popup. From here, click the CONTROLLER button to restart the Pico in controller mode.

Button Test

This is a great time to test the controller to make sure basic button presses are working.

Plug the Pico into your computer with a known good USB-C to Micro-B data and power cable. Head to this gamepad tester in your browser to see the button presses.

You can now use a jumper wire to short any mapped GPIO pin to ground -- those button presses will register on the controller tester. 

Wiring Harness

The microswitches that are actuated by the buttons and joysticks all use spade connector wiring. You can use these to connect to the terminal PiCowbell directly, or in the case of the X-Arcade, these are bundled and connected to the original PCB with JST-XH 5-conductor shrouded connectors.

Note how many of the ground runs are daisy-chained to reduce the number of connections back to the main board.

We can use the JST-XH cable sets to make the wiring simpler -- unplug them from the old PCB and plug them into the cable extensions to wire into the terminal blocks.

I used a continuity tester on my multimeter to determine the switch-to-wire correspondence and labeled each cable set before wiring.

This also included one sub-harness for the built-in power LED, and the selector switch for the enable pin.

USB Cable Extension

Use an available hole (from removing the old PS/2 and D-sub cabling) to run a USB micro-B panel mount extension. This plugs into the Pico on one end, and mounts to the exterior on the other.

You can then plug in a USB cable externally to plug into your gaming machine, and remove it when not in use.

Case Closed

Fit the bottom panel back into the case and screw it in place.