[John Floren] recently decided to make a modern clone called the Bellwether mouse ... The firmware is a mix of Microchip’s USB HID demo code and [Daniel Kao]’s Arduino code for the PWM3389 ...

This lack of USB support was a deal killer for him, so after hunting some more he settled on a clone of the Sparkfun Pro Micro. Based on the ATmega32U4, these clones were just right for his ...