The Bornhack 2017 badge is based around a SiLabs Happy Gecko microcontroller, an OLED graphical display, a few buttons and a USB interface.
The microcontroller is a Cortex-M0+ with built in USB, specifically we are using the EFM32HG322F64G and one of the 128x64 pixels OLED displays with an SSD1306 controller.
The PCB has been designed in KiCad and uses a double sided PCB, with most of the components on the front side (only the battery clips and the proto typing area are on the back side).
We have separated the hardware design files from the code and put the code in the master branch for you to have a look at and extend.