There are a number of USB stick computers available in the market at varying prices. One of them that really stands out is Tomu — a teeny weeny ARM processor that can entirely fit inside your computer’s USB port.
Tomu is based on Silicon Labs Happy Gecko EFM32HG309 Arm Cortex-M0+ microcontroller that runs at 25 MHz. It sports 8 kb of RAM and 60 kb of flash onboard. In spite of the small size, it supports two LEDs and two capacitance touch buttons.
Once you plug in this little computer, it can simulate a hard drive or mouse, send MIDI data, and even blink quickly. Tomu is a completely open source project that can act as a Universal Second Factor security token. The hardware is fully documented, and the bootloader and other code can be accessed on GitHub.
You can also turn the USB hub into a power switch for your PC. Tomu is not a full-fledged computer because of its limited I/O options, but it’s definitely an exciting tool for those who like to tinker with open source computing.
Tim Ansell, the designer of Tomu, says that the YubiKey 4 Nano is the inspiration behind the board. The software for the board still requires improvement, but the necessary bootloader code is complete and working. So it can be flashed onto the board using a Raspberry Pi.
You can buy Tomu from Crowd Supply starting at $30. Just make sure that you don’t lose this super small board while clearing your desk!