A Study On Vehicle Bluetooth Hands Free System Based On CAN Bus

As the level standard rise up day by day, drivers amount rises gradually. And the traffic accident goes up too. Using mobile phone in the driving is one of the most important reason of the traffic accident rise. Most country in the world published the traffic law for banning using mobile phone in the driving process. But drivers are allowed to use mobile phone with a handfree device. So lots of hand free device came up in the market all over the world. With the device the drives could use their mobile phone in the driving process, even could control the mobile phone with voice or listen to the music in the mobile phone.As a part of the car electric device, the hand free device could select the bus solution in the senor car or the bus free system in the car. The solution of this system used the CAN bus in the car. The system could read the data on the CAN bus and use the hand free device to connect the mobile phone in the car. For connecting to low CAN bus of an advanced car, on Vehicle Bluetooth Hands Free was a part of vehicle on the earth. The application of CAN bus not only improved technique of the products, but also improved the products stabilization. The wireless solution of the device is Bluetooth technique. Bluetooth technique was a kind of short distance wireless community solution. It was used widely in the field of wireless data transfer and voice community. On vehicle system and the mobile phone shared a narrow space in a car and the Bluetooth technique was preferred for its global openly and the related advanced mobile phone provided Bluetooth function to achieve wireless connection. Its data rate was IMbps. TDD was used to realize the full duplex transmission.This thesis was about on vehicle bluetooth hands-free system based on CAN bus. It received key values from CAN bus in the car. The system returned the results of key values. The bus terminal would deal with the results. This system connected to the Bluetooth mobile phone with Bluetooth technique and controlled wireless.Firstly this thesis introduced background and trend of CAN bus technique, and then analyzed the system of Bluetooth community protocol and hands free application frame. Then this thesis prompted a solution of based on CAN bus on vehicle Bluetooth hands free system for the aim of this subject, and described hardware and software detailed. The core of this solution was BMA39 of Jiuxu Taiwan which communicated with mobile phone, and communicated with MCU and DSP in UART and PCM. CAN bus of this system was composed of CAN processor in the microchip dsPIC30F4011 and an out transceiver TJA1041. The microchip dsPIC30F4011 solved the data from CAN bus and managed the system, connected with Bluetooth model in UART; the advanced DSP technique were used to cancel echo and noise.At last, the system went through the road test to debug the technique parameters to reach the request of the system design and finished the sample successfully.