Nintendo has something of a reputation for releasing quirky hardware accessories for their consoles and handhelds. For example, the Super Nintendo (SNES) had a computer-style mouse that was compatible with a surprising number of games. But the Game Boy Camera takes the cake for oddest accessory. It was a digital camera that users could insert into a Game Boy's cartridge slot to snap grainy 128 x 112 pixel grayscale photos. But the only official method for getting those photos off of the device was with the Game Boy Printer. Unofficially, Matt Gray designed this handy adapter that lets users wirelessly transmit Game Boy Camera photos to their smartphone.
The Game Boy Camera stores up to 24 photos in its built-in memory. That storage is persistent, so photos remain even after the user turns off the Game Boy's power or removes the Camera. Hackers in the past devised methods for copying photos from the Camera's internal storage to removable memory cards, but those methods are cumbersome. Gray's adapter makes the process quick and easy. All a user has to do is plug the Camera into the adapter and turn it on — a Game Boy isn't even necessary. The adapter will then make any photos on the Camera accessible through a self-hosted website, which the user can visit through a web browser on the same local network.
The adapter achieves that by tricking the Game Boy Camera into thinking it is in a Game Boy. There are two important pieces of hardware that enable this functionality: a Raspberry Pi Zero W single-board computer and a GBxCart RW. The normal purpose of the GBxCart RW is for backing up video game cartridges, but it can also pull data from the Game Boy Camera. You could plug that into any computer and use the provided software to backup the photos, but Gray's adapter streamlines the process. The Raspberry Pi has a script to automatically backup the photos and then publishes them on a self-hosted webserver. Users can access that webpage by connecting to the Raspberry Pi's access point or if they're both connected to the same network.
The other components inside the adapter add convenience. Power comes from a 500mAh LiPo battery through an Adafruit Micro-Lipo charger/distribution module. A latching switch disconnects power when the adapter isn't in use in order to save battery life. Gray designed the simple 3D-printable enclosure in Autodesk Fusion 360. If you want to build your own adapter, he published a guide and all of the necessary files on GitHub.