Bluetooth Stereo speakers

Student: Brendan Lee

Supervisor: Neil Bergmann

Category: Engineering Thesis Project - Computer Systems

The aim of our project is to build a wireless stereo system using Bluetooth technology, allowing a music player (music source) and speakers/headphones (receivers) to be connected without using wires. Our prototype system is implemented using HCV Wireless’ BlueMod, a Bluetooth-qualified Single Board Computer (SBC) and integrating it with MP3 CODEC hardware that we have designed and built to run as an add-on to the Blue-Mod. The system is demonstrated by using two of our Bluetooth hardware modules, one connected to music source giving it audio at line-in signal levels and the other providing an line-out level output to a set of amplified stereo speakers or headphones, showing real time music data compression /decompression and transfer via Bluetooth RF link.

The hardware is based around the MAS3587F MP3 codec from micronas. The codec can both encode and decode MP3 audio data, making it very well suited to this application. The codec is controlled using the I2C protocol and has an 8 bit data bus for both sending and receiving the digitised audio stream. This data bus is connected to a 74LV245 bi directional octal bus transceiver. This allows the hardware to both send and receive data using only one 8-bit bus.

The BlueMod modules use the motorolla coldfire MCF5272 processor and run the mC-Linux operating system. The hardware is connected to the BlueMods using the two 64 bit accessory connectors mounted on the BlueMod’s PCB. All audio inputs and outputs use standard 3.5 mm stereo plugs.

At this stage all hardware design has been completed and all testing has shown the hardware to work properly performing the functions for which it was designed.

Thesis Document (PDF)