This presentation shows the possibilities on how to build an open source Bluetooth device firmware to enable various new IoT and Maker community use cases. It provides an extensive overview on how to use the Mynewt project to build an open source Bluetooth device firmware for Nordic nRF51 and nRF52 class of radio chips and then interact with them using Linux or Zephyr operating systems. For example utilizing Linux on Minnowboard or Zephyr on Arduino 101 systems. With full Control over the Bluetooth device firmware, the possibility for new and interesting Applications are endless.