ToothHack: An Investigation on a Bluetooth Dongle to Implement a Low-Cost and Dynamic Wireless Control-Signal Transmission System

Almost any electronic project that requires Bluetooth communication, relies on readymade Bluetooth Modules. These readymade solutions come with different models which are quite ready to be used with microcontrollers, but they have their tradeoffs depending on the use case. What if there is a way to set up a Bluetooth communication system with less setup time and more reliability while featuring some basic and important features like low cost, easy availability, and bi-directional communication for data transmission? In this paper, an investigative experiment is presented to find the solution for implementing such a Bluetooth communication system for microcontrollers, especially for development-oriented projects. This experimental solution of Bluetooth communication technique has the potential to allow wirelessly perform controlling tasks for other devices using simple interfacing, and fast prototyping for short-range wireless communication with popular platforms like Arduino or Raspberry-Pi, etc. in little to no time hassle-free. In the experiment, an attempt is carried out to replace traditional Bluetooth Modules for microcontrollers by hacking an easily accessible Bluetooth audio dongle. Transmitted 2V (peak-to-peak) sine and square signals from a laptop computer and a mobile phone with 100% media volume received as 3.28V signals by the audio dongle, meaning the experiment works and the system has a maximum gain of 1.64.