If you want a little mayhem on your Christmas tree, you can check out [Sprite_tm]’s tiny PC Christmas ornament. With 3D printing, that isn’t such a tall order, but [Sprite]’s does have a unique ability: it plays DOOM, as you can see in the video below.
The device uses an ESP32, and while [Sprite] had ported the iconic shooter to the microcontroller before, he decided to use a Game Boy port that is more lightweight instead. There were a few reasons for the choice, including the ability to do Bluetooth so you could connect controllers so you can play the game. The only catch was he had to pull off the flash memory and replace it with a larger one (see the second video below).
Granted, the screen is tiny, so it is sort of a novelty. But if you want to have a go, the files are all there. As you might expect, there is a tiny battery and the circuitry required to recharge it, as well. We’d probably make an adapter to let it charge from the Christmas lights, but that can wait for version 2.
The input device handling is a bit strange. Bluetooth BLE devices will automatically grab an input device that is in pairing mode. There is no provision for connecting using the “normal” Bluetooth mechanism. A fun project and you could use the case for some other tiny projects, too. A larger flash on an ESP32 has lots of possibilities, as well.
If you need a primer on the ESP32, we got it. If you want to play DOOM on something truly strange, try seven-segment displays.