This project is a small dongle carrying a SAMD21 from Atmel along with a CR2032 battery holder and USB b port for use as a portable fusee launcher.
I built it to get a little more familiar with the Cortex M0 offerings from Atmel, as well as to make myself a nice, compact device that I could use for Switch experimentation as well as other projects.
This project is using the UF2 bootloader, which is the most amazing idea that anyone has ever come up with - thanks, Microsoft! The UF2 bootloader impersonates a virtual flash drive when plugged into USB and reset is double clicked, allowing reading and writing firmware with a simple drag/drop operation. Very slick!
The project is also compatible with the Arduino platform using the bossac loader. Personally, I use an STM32 blue pill flashed to CMSIS-DAP to do my low-level programming, but for a simple setup Arduino can't be beat!
If you are interested in purchasing the V2, you can check out the Tindie project page here. Hatch (the designer of the open-source case) gets 10% of every sale of board+case!
If you would like to purchase the original board without USB B, it is also available on Tindie here
The badass open source case design is available on Thingiverse here:
The github containing all code for the product is here:
And the discussion thread of me chatting during the build is on gbatemp
Firmware files for the three most popular loaders (hekate, ReiNX, and SXOS) are found below in the files section. To switch, plug the board into USB, double click reset, and drop the UF2 file onto the drive called FIRMWARE that pops up