Witnuino is a small touch-interactive, battery driven handheld Arduino Uno R3 "game console" I designed, coded and built. It's running my recreation of the puzzle language from the game "The Witness", which is one of my favorite puzzle games. Witnuino packs around 50 puzzles, most of them customly designed. The puzzle logic is recreated to work like the original game. The challenge & fun with this project was to keep the code incredibly simple, efficient and small, due to the limitations of the Arduino Uno R3 (2KB SRAM, 32KB FLASH, 1KB EEPROM). A flood-fill based solver is implemented and I even created a separate level editor software to create levels. The levels are written onto a microSD card in a simple custom designed save system. The progress of the player is stored there as well, so the device can be turned off while keeping the last save state. The code can be found here.