A hobbyist has repurposed the classic Game Boy Advance Link Cable with a Raspberry Pi Pico to make the GBA function as a Switch controller. The open‑source Joypad OS firmware translates button presses into HID signals, enabling two‑way communication and the possibility of using other retro pads with modern consoles.

Turning a Game Boy Advance into a Nintendo Switch Controller Using the Original Link Cable

The Game Boy Advance, released in 2001, became a beloved handheld for its library of classic titles and its Link Cable that allowed two units to connect for multiplayer battles and data trades. Decades later, a hobbyist has repurposed that same cable to turn the GBA into a functional controller for the Nintendo Switch. The build relies on a Raspberry Pi Pico programmed with open‑source firmware that translates the GBA’s button inputs into signals the Switch understands.

Robert Dale Smith, the creator behind the project, used his own Joypad OS framework to make the Pico act as a bridge between the legacy hardware and the modern console. Joypad OS is designed to present a variety of retro controllers as generic USB or Bluetooth gamepads, which means the Switch sees the GBA as a standard controller without needing any special drivers. The firmware also supports two‑way communication, so data can travel from the Switch back to the GBA if desired.

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Wiring the adapter is straightforward: the Pico’s GPIO pins are soldered to the four wires inside the original Link Cable, preserving the cable’s original connectors so the GBA can still be plugged in as usual. Once the Pico is powered, it reads the state of the D‑pad, A, B, L, and R buttons and sends corresponding HID reports to the Switch over its USB‑C port. Because the Pico appears as a USB human interface device, the Switch treats it like any other third‑party controller.

Beyond the GBA, Smith notes that Joypad OS supports other retro pads such as the Nintendo 64 controller, the Sega Genesis six‑button layout, and even original PlayStation controllers. Enthusiasts could therefore wire those classics to a Pico and use them with the Switch, opening up a wide range of nostalgic control options. The project’s source code is available on GitHub, allowing anyone to compile the firmware for their own Pico or adapt it to other microcontrollers.

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A related effort highlighted earlier shows how a Raspberry Pi can revive a PlayStation‑style PC dongle that Sony never released, proving that small boards continue to bridge gaps between old and new gaming hardware. Those interested in the technical details can follow the links below to examine the schematics, firmware, and build guides.

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