Detailed explanation of the design of IoT vehicle terminal system based on RFID technology

Today, with the rapid development of informatization, the application of digital information is becoming more and more mature, and various industries use it to optimize the industrial structure and seize the market. Currently, most of the vehicle-mounted terminals that are widely used only use the recording function of the camera and cannot transmit monitoring information back to the monitoring center in a timely manner. They are not true real-time remote monitoring terminals and cannot meet the needs of automated operations. With the rapid development of the current logistics industry, the introduction of Internet of Things technology into Logistics industry management will play a multiplier role in improving the efficiency of logistics companies. The RFID-based Internet of Things vehicle system introduced in this article is an intelligent system running in the vehicle terminal. It is installed behind the transport vehicle. Through RFID technology and other dynamic information collection technologies, it automatically communicates with the control center without manual operation to realize vehicle control. Full control of the process.

1 Overall analysis of the system

The Internet of Things vehicle system is developed on the Linux platform using the ARM11 embedded processor, and adopts GPS positioning, GPRS communication technology, RFID wireless radio frequency technology, etc. The bottom layer of the vehicle-mounted terminal is based on an embedded platform. The embedded software is implanted into the logistics vehicle-mounted terminal and the control of other functional modules is completed through the written control program to achieve the following functions:

1) Complete information transmission in real time;

2) A card reader is embedded in the remote terminal to identify and record the loaded goods;

3) Achieve precise positioning throughout the entire process;

4) Use the camera device to obtain the required image information;

5) Communication with the control center;

2. System hardware design

The IoT logistics vehicle-mounted terminal system mainly consists of the ARM11 core system, GPS module, GPRS module, RFID identification module, image acquisition module, etc.

This system requires real-time transmission, GPS location, RFID identification information, etc., real-time dynamic tracking of vehicles, and comprehensive needs from all aspects. The CPU of the embedded system uses Samsung's S3C 6410 microprocessor, with a stable main frequency of 667 MHz and the highest main frequency. The frequency can reach 800 MHz, it integrates many peripheral interfaces, has the characteristics of high performance, low power consumption, large storage space and strong computing power, which meets the needs of this system for data processing and storage, and realizes the functions of various parts. .

The GS-91 GES satellite positioning module selected for the GPS positioning module is a high-performance, low-power consumption GPS satellite receiving engine board. It is a complete satellite positioning receiver with all-round functions, and the positioning accuracy can reach 10 m.

The wireless communication module uses the SIM300 module of SIMCOM Company. It is a three-band GSM/GPRS module that can work at 3 frequencies: EGSM900 MHz, DCS 1 800 MHz, and PCS 1 900 MHz worldwide. It can provide up to 10 GPRS multi-channel types, and supports CS- 1. CS-2, CS-3 and CS-4 4 GPRS encoding schemes, embedded with TCP/IP protocol, can quickly access the Internet through AT commands.

Nand flash is a storage peripheral. This system Stores video information in nandflash. At the same time, LINUX's Uboot, kernel, boot image and File system are also programmed into nandflash.

The remote terminal uses a camera module to complete the image acquisition function. The camera module uses the Vimicro Z301P USB camera. The module is directly connected to the embedded platform through the USB interface. The embedded system stores the images, ensuring data security. The collected image information is further compressed and processed by the embedded system and sent to the remote control center through the wireless communication module.

The radio frequency identification module uses nRF24L01 wireless radio frequency module. nRF24L01 is a single-chip wireless transceiver chip that works in the world-wide ISM frequency band of 2.4 to 2.5 GHz. It has extremely low current consumption. The system places tags on the transported goods and uses the RFID Reader on the terminal to identify and manage the goods entering the transport vehicle.

3. System software design

The software system of the Internet of Things logistics vehicle-mounted terminal uses the embedded Linux operating system as the development platform. First build the Linux operating system on the PC, and then set up a cross-compilation environment. In this process, GPS positioning information, GPRS wireless transmission, image collection, RFID identification information collection, etc. are all written on the PC using C language, and then cross-compiled to generate executable files and run on the S3C6410.

3.1 GPS module

The GPS module program is the key and foundation of this system. It mainly completes the automatic collection of information such as longitude and latitude, vehicle speed, acceleration, altitude, and azimuth. After opening the device, you first need to initialize the serial port, set the baud rate, data bits, stop bits, check bits and other parameters, then open the serial port to read the original GPS information, and finally call the function gps_phame(char*line, GPS_INF0*GPS); Analyze GPS information.

3.2 GPRS module

The GPRS module program is the key and foundation for realizing remote wireless networking and real-time data communication. It mainly completes functions such as interactive data communication, SMS receiving and sending, online data updating, and dispatch center remote command control. In order to take into account both data communication and SMS sending and receiving functions, the GPRS module does not use TCP/IP transparent transmission mode, but works in AT command mode. Data communication uses TCP/IP protocol. The communication format is custom PDU double-byte encoding mode. SMS uses International standard PDU data format.

3.3 Trip playback

This system can locate the vehicle in real time and store the driving route in nand flash. The video information is collected at the vehicle terminal. The video information can also be stored in nand flash and the driving route information can be played back.

3.4 Image acquisition module

This system uses the Linux2.6.36 kernel, which uses the UVC driver v412 (short for video4linux2) framework. v412 provides a set of interface specifications for Linux video device programs, including a set of data structures and underlying v412 driver interfaces.

3.5 Collection of identification information

nRF24L01 communicates with the Linux system through the UART serial port. It can receive data from 6 different channels in the receiving mode. The nRF24L01 set to the receiving mode can identify these 6 transmitters. The nRF24L01 records the address after confirming receipt of the data. The address sends a response signal to the target address, and data channel 0 at the sending end is used to receive the response signal.

nRF24L01 initialization part of the code is as follows:

4 Results and analysis

The upper computer monitoring and control operation interface of this system is developed in Java language. The management platform combines GIS information to display the geographical location of the currently monitored vehicles in real time to facilitate querying of relevant information and effective supervision.

5 Conclusion

This article proposes an Internet of Things vehicle terminal system based on RFID technology, selects the embedded Linux operating system and S3C6410 processor as the software and hardware platform, and successfully develops a prototype. Through real-time remote monitoring of vehicles of logistics companies, logistics efficiency can be improved and logistics costs can be saved; through vehicle positioning, vehicle condition information monitoring and other functions, the entire driving process of vehicles can be monitored to improve driving safety. The use of RFID-based IoT logistics vehicle-mounted terminals introduces advanced Logistics Management concepts into the production and operation process. At the same time, because the system uses a wireless network, real-time communication with the control center can be achieved as long as it is within the coverage of the GPRS network, which is very good The realization of real-time precise positioning monitoring has very practical value.