The Studies On Vehicle Hands Free System Based On Bluetooth

Bluetooth is one of the open protocols about wireless communications of data and voice,based on low price and short distance. Bluetooth uses the distributed network architecture, thequick frequency modulation and the short package technology, and supports the communications ofpoint to point and point to multipoint. It works on the global general frequency of 2.4GHz ISM(Industry, Science, Medicine). Its data rate is 1Mbps. TDD is used to realize the full duplextransmission.Bluetooth products have many advantages, such as small volume, low power, etc.Bluetooth technology has many applications including mobile phone, PDA, computer, printer,digital camera, and so on.It is great application prospect that Bluetooth is used in the automotive electronic equipment.Parrot Company has developed the vehicle Bluetooth kit which is used to control the vehicle withaudio by drivers. Motorola Company has also produced a Bluetooth automobile tool kits for theautomobile producers.The hands Bluetooth kits can be connected with the automotive kitswirelessly, for instance, open the vehicle door with the wireless remote controller, and exchangedatabase with the vehicle examination system in the vehicle wirelessly. The study of this thesis is todesign vehicle hands free system based on Bluetooth, which is wireless communication betweenBluetooth mobile and vehicle hands free system and realize hands-free function.This thesis introduced Bluetooth background and trend, analyzed Bluetooth Specificationincluding Core protocol and Hand Free Profile, presented a plan of vehicle hands free system basedon Bluetooth, and expatiated the plan from the software and hardware. CKM3 Bluetooth modulemade in Taiwan Tianying Company is the core chip in the plan. CKM3 is equivalent to a wirelessdispatcher and communicates with Bluetooth mobile. Its UART and PCM port respectively connectto microcontroller and DSP. Microcontroller run the whole system in phase, its serial portscommunicated with Bluetooth module, I/O ports drived liquid crystal display etc; Voice processingadopted DSP in advanced, so that the system had clear voice environment. In the part of hardware,choosing chips,characteristic and designing interfaces were expatiated, calculated to abase thepower consumption of system adequacily, rationally position the high power consumption devicesto heat loss well. In the part.of software, that course of Bluetooth equipments communication andBluetooth module serial communication is analyzed, the flow of system hands-free functionemploying by C language was gave, as well as the model machine was debugged and realized its basic function.