However, I was rather intrigued when I recently ran across the Tomu. The difference between the Tomu and most other USB stick computers I’ve come across? It’s so small it fits entirely inside your computer’s USB port.
The board is based around Silicon Labs “Happy Gecko” EFM32HG309 Arm Cortex-M0+ microcontroller running at 25 MHz, with 8 kb of RAM and 64 kb of flash onboard, and despite its small size, supports two capacitance touch buttons and two LEDs. The bill of materials of the board literally consists of just 12 parts, and that’s including the PCB.
The ultimate goal of the Tomu project is for it to be useable as a second factor authentication device. While the hardware is ready, the software is still a work in progress, although the necessary bootloader code is complete and working and can be flashed onto the board using a Raspberry Pi.
The hardware is fully documented, and the bootloader and other code are all available on GitHub. The project is entirely open source with the hardware under the CC BY-SA 4.0, and software under the Apache License Version 2.0.