Mobile gaming has come a long way since it was first introduced several decades ago, perhaps most notably with the Game Boy handheld console from Nintendo. But this was not good enough for Fabian Grosso, as he wanted to build a device so small and cheap that it could easily be carried on a keychain. Furthermore, the tiny game console would also have to be rechargeable and easy to program.
The project, named the Game & Light, is based around a single ATtiny402 microcontroller, which has a mere 4KB of flash and 256 bytes of static RAM, leaving not much space for games. The back of the custom PCB contains not just the MCU, but also a connector for adding a 128x32px OLED screen and a MOSFET that acts as a switch between the battery and the rest of the circuit. Lastly, a button was included that allows the user to have a singular input for whatever game might be played or to light up a bright LED.
Batteries are notorious for taking up large amounts of space relative to their capacity, so rather than going with a typical lithium polymer battery pack, Fabian opted to include a lithium-ion capacitor instead. This specialized component is a hybrid between a lithium-ion battery and a supercapacitor, thus giving it properties from both. They include having a higher energy density than a capacitor, being extremely reliable, and being easy to recharge. In this circuit, the microcontroller itself manages the charging process rather than a dedicated module.
Due to the very limited amount of memory and non-volatile storage space, any game created for the Game & Light would have to fit within a very limited set of constraints. Therefore, Fabian came up with a simple design that combines elements from Flappy Bird and the Dinosaur Game that comes with the Chrome web browser. In it, the player must time their button presses so that the character jumps over enemies, which move from right to left at random speeds. Meanwhile, a background filled with pixelated trees, clouds, and birds scrolls past.
As seen in his demonstration video on YouTube, Fabian was quite happy with how well the Game & Light functions, although he does acknowledge that adding a more powerful microcontroller would allow him to add more content to the game. For more information, you can read his write-up here on Hackaday.io.