Abstract: This paper introduces a design scheme of steering wheel control system based on Bluetooth technology. The use of Bluetooth transmission technology to realize the electronic optimization design of the steering wheel panel switch of the automobile overcomes the drawbacks of the need to look for the switch in the traditional driving process, so that most of the operations are realized on the steering wheel, and the driving of the car is more convenient. The control system adopts the Bluetooth module based on the BC219159 Bluetooth chip; the main control device uses the STC89LE516 as the controller to collect and process the signal of the button on the steering wheel and then send it to the Bluetooth chip for wireless transmission; the slave device receives the master device from the Bluetooth module. After the signal, the slave control chip STC89C516 sends corresponding commands according to different signals. The CAN bus is used to control the use of the four systems of air conditioning, audio, cruise control and car lights in the car. At the same time, the LCD screen is connected to facilitate the driver to control each. Kind of equipment. The system uses PWM to control the strength and weakness of each function and reduce hardware costs. Tests show that this system has the advantages of low cost, good reliability, high security and versatility.
1 Introduction
High-tech applications have changed people's lives. As a basic vehicle, people also want to make driving operations easier and more convenient, and to communicate and communicate with the outside world in time.
Bluetooth technology can provide technical support for the realization of this new type of automotive electronic information system. Bluetooth technology can be used to wirelessly connect various electronic devices in a car to form a "vehicle network", which includes automotive electrical control equipment. , audio and video equipment, vehicle positioning and monitoring equipment, various sensors and their control systems, vehicle security systems and vehicle navigation systems.
As a new short-range wireless spread spectrum communication technology, Bluetooth has the characteristics of small size, low power consumption, openness and interoperability. Compared with the traditional transmission of data by cable and infrared, it has the following advantages:
(1) Strong anti-interference ability; when working with various electronic devices with wireless communication functions such as laptops and mobile phones for wireless Internet access, there is a large amount of electromagnetic interference to other electronic devices in the vehicle. Bluetooth technology features fast acknowledgment and frequency hopping schemes to ensure link stability. It divides the frequency band into several frequency hopping channels. In one connection, the radio transceiver continuously "jumps" from one channel to another channel according to a certain code sequence, and only the transmitting and receiving parties communicate according to this rule, thereby avoiding Interference; the instantaneous bandwidth of frequency hopping is very narrow, but this narrow bandwidth is spread hundreds of times into a wide frequency band by spread spectrum technology, making the possible influence of interference small. (2) No need to connect signal lines, reduce costs and reduce the space occupied. (3) It has the basic characteristics of electromagnetic waves, has a large power, can increase the transmission distance, and has no limitation of angle and directivity. It has wall-through property and can be reflected and diffracted between objects. (4) The power consumption is very low, and many components can be connected at the same time, and the transmission speed is fast.
The Bluetooth-based steering wheel control system introduced in this paper uses a network scheme combining wired and wireless to form the entire control system.
2 system design
The system realizes the control functions of constant speed cruise, sound, air environment inside the car, and headlight illumination in the car through buttons installed on the steering wheel.
The control system is designed based on Bluetooth technology, and its hardware components mainly include two main parts: Bluetooth master control device and Bluetooth slave control device. The master control device collects the button signal through the ZLG7289, and then sends it to the microprocessor STC89LE516 for processing. The microprocessor sends corresponding commands and data to the Bluetooth module BC219159B according to different button signals. The Bluetooth module is in the master and slave devices through the wireless network. The Bluetooth module transmits a command and data after establishing a link, and the microprocessor of the slave device sends different commands and data to the CAN bus according to the corresponding signal, and other vehicle systems connected to the CAN bus implement related functions according to the command, LCD Displays various functional statuses. The hardware block diagrams of the Bluetooth master and slave devices are shown in Figure 1 and Figure 2, respectively.
Figure 1 Hardware block diagram of the Bluetooth master device.
Figure 2 Hardware block diagram of the Bluetooth slave device.
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Hunan Furui Mechanical and Electrical Equipment Manufacturing Co., Ltd. , https://www.thresher.nl