Abstract: This paper uses the Internet of Things technology and the on-board LIN bus technology to collect the data collected by the car battery sensor to the remote server. The remote server realizes the remote monitoring of the vehicle battery data and the fault diagnosis of the battery through data storage and judgment display. The function solves the drawbacks of the existing car battery diagnosis that must be diagnosed by wired means.
Abstract: In this paper, we use the Internet of things technology and vehicle LIN bus technology to collect the data from the car battery sensor to the remote server, remote server achieves the remote monitoring and fault diagnosis function of the battery through the Data storage and display, to solve the shortcomings that existing car battery diagnosis must be diagnosed in a wired way.
Keywords: Internet of Things; LIN bus; monitoring
Key words: Internet of things; LIN bus; Br\u003e CLC number: TP315 Document code: A Article ID: 1006-4311(2016)31-0092-02
With the gradual development of wireless communication technology and the concept of Internet of Things, Based on GPRS, IoT smart home, water and electricity wireless meter reading system, intelligent transportation field has developed rapidly. However, the data acquisition system and GPRS are directly integrated, and an intelligent product for vehicle battery diagnosis is developed. Most of the products are only connected with the existing GPRS module to realize wireless transmission of data. However, this "assembled product" cannot control the GPRS module, which brings a lot of inconvenience to its operation and debugging personnel. Especially for the equipment used in the research and development phase of the vehicle battery matching, there is no such thing as the development of the vehicle-based battery diagnostic system based on the Internet of Things. This kind of hybrid network wireless gateway is imperative, providing a more convenient way for car battery matching work.
1 System frame design
This system mainly consists of two parts: car battery signal acquisition system and remote signal display diagnosis system. The working principle of the system is to use the battery sensor (the current, voltage sensor and battery temperature sensor of the car battery) to collect the current, voltage and temperature signals sent to the remote server through the on-board LIN transceiver and the Internet of Things, the remote server. The terminal automatically stores data for the collected signals and automatically generates a diagnostic report to judge the performance and working environment of the car battery. The hardware frame structure of the system is shown in Figure 1.
2 System hardware design
The system adopts STM32 development board as the development platform, selects LIN transceiver TJA1020 for signal processing, and selects SIM300 module with GPRS function and short message function to transmit data with server diagnostic center. The hardware design of the system includes power circuit design, crystal reset circuit design, LIN bus circuit design, communication circuit design and so on.
2.1 Design of power circuit and crystal reset circuit
The design of power circuit is mainly considering that the voltage required by STM32 microcontroller is 3.3V, and the battery on the car is 12V, so the design of power module is only It is necessary to convert the 12V voltage of the battery into a voltage of 5V. In order to prevent accidental short circuit, a fuse protection circuit can be added in the design process of the power supply circuit. The crystal reset circuit is designed directly to the peripheral circuitry of the STM development board. The power circuit and the crystal reset circuit form the smallest system of the system.
2.2 LIN Bus Circuit Design
The LIN bus TJA1020 transceiver used in the system is a physical media connection, which is the interface between the LIN host/slave protocol controller and the LIN transmission medium. The transceiver can operate in a low power mode with virtually no current consumption and reduced power loss. The TJA1020 transceiver delivers the signal collected by the battery sensor to the MCU, which realizes the function of transmitting and receiving the circuit signal, and the TJA1020 transceiver has an isolation function to effectively isolate the interference signal. The bus circuit diagram of the system design is shown in Figure 2.
2.3 Communication Circuit Design