Taking a Raspberry Pi and sticking it in the housing of a Game Boy isn’t a new project, though most of these retrofits were undoubtedly more modern than the original handheld console. They usually had more buttons, backlit color TFTs, and ran off modern Li-ion batteries. A project on Spritesmods named the DMGPlus is interested in utilizing the Pi in a stealthier way; instead of using it to update the older console, the DMGPlus is recreating how playing one of the first handheld game consoles used to feel.
A video demonstration shows a familiar green-tinted screen as it loads up Tetris DX. The design keeps as much of the existing hardware as possible and finds ways to interface with all of it: the display, buttons, cartridge, speaker, and the link port. In an authentic Game Boy, one main circuit board interfaces with all the other hardware, making it the main target for a replacement here. Since the Raspberry Pi doesn’t have enough pins and isn’t normally compatible with the signals needed for the LCD, it needs a few tweaks to make it run. To fix the difference in logic levels — the Game Boy works on 5V while the Raspberry Pi uses 3.3V signaling — an FPGA is needed to do a signal conversion and interface with the cartridge, as well as handling a handful of level shifters to move between signal levels.
The project post includes detailed, labeled schematics and written instructions for building out the necessary components and getting it all connected. All said, the only difference in look in the assembled product is a non-stock volume button peaking out of the casing. Still, its CPU and GPU are now a couple of hundred times more powerful. The work that went into fiddling out the specifics to make it run as authentically as possible was intense — you can view all the documentation on GitHub.
t the end of the years-long process of designing and building it, Sprite notes that maybe the end result wasn’t worth what it took to get there — the green hue of the display is nothing to write home about — but on a project like this, the journey itself is most of the fun.