RFID technology is widely used in the market. In foreign countries, RFID has been widely used in industrial automation, commercial automation, transportation, logistics and many other fields. Its unique high accuracy and rapidity greatly reduces the logistics cost of enterprises, and improves the market competitiveness and service efficiency of enterprises. This paper designs a complete intelligent garage control system. The garage model adopts the “back” design scheme. This scheme has passed the verification and actual information collection in the model garage, and can meet the actual application. In the hardware part, STC 11f32xe MCU produced by STC company is used as the control core. The overall design of the system hardware is carried out, and the specific design of each function module in the hardware system is introduced in detail below.
The garage model is divided into two parts, the whole structure part and the intelligent car part.
The whole model is designed as a single module in the overall frame design of garage. In this way, the garage model is easy to operate and simulate a variety of application scenarios in the function demonstration and collection of garage data. In the process of moving, the volume is reduced and the space is compressed. The internal design adopts the “back” shape, so that the in and out do not interfere with each other, and the waiting for the in and out situation caused by the mutual occupation of roads by the in and out vehicles is avoided. The structure and function of the whole model are designed independently by blocks. In the place where there are few vehicles and parking demand is not big, only a part of the model can be built to meet the demand. In places with dense population and many vehicles, we can expand horizontally and build more modules; It can also be extended downward to make a double-layer or multi-layer three-dimensional garage to meet the actual needs, increase its practicability and facilitate later promotion.
The design of the intelligent car is completely in accordance with the national robot competition standard. The vehicle is powered by DC power supply, which is convenient for the system to manage the power supply and reduce the power consumption of the equipment as much as possible. The connection of voltage regulator chip between power supply and controller and other devices can not only make the system power supply provide the current and voltage we need, but also effectively protect the power supply. Using STC 89C58 single chip microcomputer as the controller of the simulation vehicle, it can make timely response to the changes in the vehicle operation, which is convenient for the simulation person to drive the vehicle forward, stop, retreat and other operations in and out of the garage. Considering the demand and cost, STC 11f32xe is selected as the control core. In the whole system, stc11f32xe MCU reads the information from the card reading module, processes the obtained information in time, and sends the processing results back to the card to complete the information exchange.
The circuit diagram of the program download module is shown in Figure 1. Firstly, when the chip is not working, the PC sends a signal to STC 11f32xe chip through the serial port (DB9) to make the chip wait for download. When the MCU is powered on, the computer terminal and MAX232 chip are connected through t1out0 and r1in0. After level conversion, the computer terminal is finally connected to the target chip through t1out0 and r1in0, and the program is downloaded through the whole circuit.
MAX232 chip in this download circuit, by 1,2,3,4,5,6 pins and four capacitors to generate + 12V and – 12V two power supply, to provide RS-232 serial port level needs. TTL / CMOS data from t1in, t2in input into RS-232 data from t1out, t2out to the computer DB9 plug; The RS-232 data of DB9 plug is converted from r1in and r2in input to TTL / CMOS data and then output from r1out and r2out to complete the level conversion.
The circuit of radio frequency identification part is shown in Figure 2. After the magnetic card enters the magnetic field generated by the antenna, it receives the radio frequency signal sent by the reader. With the energy obtained by the induced current, it sends the product information stored in the chip through TX1 and TX2. After the reader rc522 reads and decodes the information, it sends it to STC 11f32 through m-mfmosi, m-mfmiso and m-mfrst for relevant data processing.
MF rc522 chip uses its advanced concept of modulation and demodulation to realize the passive non-contact communication mode and protocol at 13.56MHz. The communication between the internal transmitter and the ISO 14443a / Mifare card is realized by TX1 and TX2. The hardware receiver part provides a robust and effective demodulation and decoding circuit for processing iso14443a compatible response signals. The communication with STC 11f32xe through m-mfmosi, m-mfmiso and m-mfrst adopts UART (similar to RS232) mode with less connection, and the data transmission rate is up to 424kbit / s, which is conducive to reducing the connection, reducing the size of PCB board and reducing the cost.
The display circuit is as shown in Figure 3. The 12864 LCD screen is used to display the unified visual operation of the same operation of our customers and ourselves in the actual scene.
The design of the whole intelligent garage takes the practicability and stability into consideration. Based on the data statistics and analysis of the current large-scale use of traditional garage and the garage model, each parking area adopts an independent design scheme in terms of function and structure. In the process of actual use, the parking area can be increased or decreased according to the actual demand on the basis of the existing garage model according to the needs, so as to meet the parking needs. In the process of program design, according to the different operation scenarios of the magnetic card, multiple working modes are set to reduce the interaction between programs as much as possible, so as to achieve the universality and error free operation of the system.
Editor in charge: CT