Nintendo has always been known for their interesting innovations, and one of the most ambitious was the GameCube-Game Boy Advance Link Cable. That accessory let you connect your Game Boy Advance to your GameCube so that you could use it as a controller, to share data, to unlock additional game content, and even to use it as a second screen. Many people preferred to use the Game Boy Advance instead of the GameCube’s somewhat quirky controller. Now you can continue to do that with emulators — or even new games — thanks to this GBA Bluetooth HID device.
The GBA Bluetooth HID was developed by Shyri Villar, and in principle it turns your Nintendo Game Boy Advance into a standard Bluetooth gamepad. That means you can use it with any computer, smartphone, or tablet that supports Bluetooth controllers. You could, for instance, pair it with your Raspberry Pi running RetroPie in order to play emulated Game Boy Advance games in the way that they were meant to be played. You can even use it to play new Steam games, so long as the Game Boy Advance’s buttons are sufficient for the gameplay.
It works by utilizing the same link port that was used for the GameCube-Game Boy Advance Link Cable. The device stores a custom ROM in a flash chip, and an Arduino-compatible Microchip ATmega328P microcontroller handles the boot sequence. Once booted, users can pair the device’s HC-05 Bluetooth module with whatever computer or device they want. From then on, all button presses are passed from the Game Boy Advance over Bluetooth to whatever you’re connected to. Villar isn’t selling the GBA Bluetooth HID, but the project is open source so you can build your own.