Back in 2015, an open source gaming platform called Arduboy reinvigorated 8-bit portable gaming. Since its introduction, the community has contributed many games, hardware modifications, and alternative consoles. Its creator Kevin Bates continues to design new variants, with the latest being the Arduboy Nano — it's fully functional and only one inch tall!
The original Arduboy looks like a card-sized version of a popular portable 8-bit game system from the 1990s. It includes an OLED display, a D-pad, two buttons, a lithium polymer battery, and an ATmega32U4. The limited memory and resolution push game developers to be creative.
Arduboy Nano uses the same AVR microcontroller as the original. However, Bates swapped its screen, buttons, and battery with much smaller components to achieve a height of only 26mm! The 0.49" screen only features 64x32 pixels. The reduced resolution means some games may need to be re-worked. But, otherwise, Arduboy Nano is software-compatible with its larger sibling.
Bates estimates the teeny 25mAh lithium polymer battery may last at least an hour. For sound, Arduboy Nano uses a 15mm piezo speaker. Unfortunately, the small size means the sound is not very loud.
There is not a plan to produce the Arduboy Nano as a product. At least, not yet. Bates says there are a few PCBs available for anyone who wants to build one. So to either express interest in the keychain-sized gaming system or inquire about one of the PCBs, head over to the Arduboy forum for more information.