Design Of Bluetooth Hands-free System And Implementation Of The Hardware

With the development of the science technology and gradual improvement of people’s life, mobile phones and automobiles have already entered into common crowd. At the time of enjoying the convenience to the life, people gradually pay attention to the potential danger from call when they drive. The Ministry of Transportation & Communications has already passed lawmaking that forbids call by cell phones when drivers are driving. The contradiction between driving and call by cell phones promote people to look for various means to carry out hand-free function in car.According to this actual market need, this thesis puts forward a hands-free system that has a core of Bluetooth technology. The system establishes good voice chains to cell phones making use of short distance, high speed and being suitable for voice transmission of Bluetooth technology. Call numbers, call names and message and so on transform to drivers through voice synthesis technology, so that hands and eyes of drivers are liberated. Professional echo noise suppression chip guarantees clear voice dialing and reporting and fluency communication. The keyboard system in the steering wheel and car professional power amplifier make the design to apply to the after-loading market need of the hands-free system in car. Center controller based on ARM7 controls Bluetooth model and voice synthesis model through asynchronous serial data interface, recognize the keyboard through A/D function, switch voice lines and power lines and so on through a lot of GPIO interfaces. Hard circuit design are finished and parts of circuit are debugged by using MultiSim and PADS2005.The design program in the thesis prove that the actual products are suit to market demand of hands-free system in car. Test results show that the system stability, security and low power consumption have improved than existing hands-free system in car. Clearly, the system has a broad market prospect.