[PJ Evans] had a ruined game cartridge lying around, just waiting for a project. As Activision’s F-14 Tomcat game for the Atari 2600 console, it seemed ripe for use as a project enclosure of some sort. When he came across a couple of 9-pin D-sub joystick ports, he had an idea. He realized his Rasperry Pi Zero could fit inside the cartridge. Add a power button, TV color selector, difficulty switch, as well as select and reset buttons, and you have an emulator.
[PJ]’s Pi Zero had more than enough GPIO pins to accommodate all of those buttons and switches plus a bunch more for the joysticks. Why not put the emulator inside a game cartridge? In terms of software [PJ] looked into Adafruit’s Retro Gaming with Raspberry Pi resource, which has tons of suggestions for setting up game emulators. He decided on the RetroPie operating system to help him map out all of the pins, with Stella doing the actual Atari 2600 emulation.