This paper introduces a kind of anti-loss controller for positioning of old people and children. It is based on single chip computer and adds GPS module and GSM module to realize the function of anti-loss and positioning search. It can locate and communicate at a long distance. After obtaining the location information of the target (old people and children), it can judge and select the best route to find the target. It mainly adopts STCl2C5A60S2 chip, which combines GPS and GSM to realize dual serial port working at the same time. It has high stability and low production cost. In today’s society, children, the elderly and the mentally handicapped are often lost. Every year, 200,000 children are lost, and less than 0.1% of them can return to their families. At present, the anti-loss devices which have been mass-produced are mainly used for articles, but seldom for personnel. The main audience of the anti-loss device in this paper is human beings. It realizes the long-distance rapid positioning of personnel and facilitates fast search. The lost-proof device for old people and children is also called “personal positioning terminal”. This project combines GPS technology, GSM technology and GIS technology in the field of communication and intelligent monitoring. Real-time accurate positioning of the target object or person. It can be widely used in security system and medical treatment. It can be widely used in car rental industry/mechanical equipment and other anti-theft tracking, children and the elderly security, personnel management, criminal tracking and other occasions. At present, most of the popular anti-loss devices in the market are on the high side of the market price, which can play a better anti-loss alarm function, but most of the anti-loss devices do not have a more accurate positioning function, or there are limitations on the scope of work, which brings inconvenience to daily use. The anti-loss device has perfect functions and can solve these problems in a better coordinated manner, so as to truly achieve all-weather, all-round and the whole process of anti-loss.
It has the characteristics of low production cost, simple circuit, strong anti-interference, low power consumption and strong practicability.
The receiving module of GPS receives data from satellite and calculates the coordinates of the current azimuth. People can dial and send AT command information to the GSM module on the lossless protector according to the security number set on the microcontroller. The lost-proof device in the holder’s hand will parse the received location information according to the instruction information, then send it to the security number through the GSM module, so that the family can find the lost person more conveniently according to the received location information. With the maturity of GSM technology, the signal transmission of GPS has changed from radio and private network transmission to GSM public network transmission. The system realizes the function of monitoring and losing-proof for mobile targets. The short message function of GSM is used to realize the signal transmission, and the response speed is fast. After calculating and processing the received GPS information, the longitude, latitude, speed and direction of the moving target are obtained, and the existing GSM network is used as a communication tool to transmit positioning data. The system structure can be divided into three modules: location information acquisition and transmission (GPS module), information transfer (GSM mobile communication system), information analysis and processing (MCU operation processing). The positioning system is composed of control unit MCU (STCl2C5A60S2), GPS positioning module (Ublox NEO 6M), thermostatic element GSM module (SIM900A), LCD display module (LCDl2864) and power module. As shown in Figure 2, when the user transmits the location command to the terminal by short message, the terminal obtains the position coordinates by GPS module and GSM module, and then sends the coordinates to the user by short message. GPS module completes the function of receiving GPS messages.
GSM undertakes the task of locating and sending short messages. MCU sends AT instructions to the module, and then parses the value returned by the module, so as to determine whether the required function is successfully enabled, and then proceeds to the next instruction. Set the receiver number and send short message: Send array command to module through serial port, return to AT CMGS=” 86XXXXXXXXXXX”, edit the information package to send to the recipient in text (or PDU information) format.
If the module returns value of “OK”, the message will be sent successfully. At present, the development of GPS is relatively advanced, and the accuracy of civil GPS can reach 3 m. The GPS module used in this device is Ublox NEO 6M with compact shape; [6] KickStar technology is adopted, the first positioning time (TTFF) is not more than 1 second, the hot start time and auxiliary start time are not more than 3 seconds, and the cold start time is less than 29 seconds; it can support GPS, GALILEO, SBAS (WAAS, EGNOS, MSAS, GAN) hybrid engine, and support AssistNow Online and AssistNow Of GAN. Fline and other A-GPS services; and real-time update the location of geographical information at 5 Hz positioning update rate, accurate positioning state can reach 2.5 MCEP, SBAS state can reach 2.0 MCEP. The software flow is shown in Figure 3 below. During the operation of the software, 5L MCU receives positioning data from serial port l all the time. Serial port 2 adopts the highest priority.
When the GSM module connected by serial port 2 has a designated telephone call in, it calls the GSM subroutine and loads positioning information into the S2BUF storage area. The GSM module transmits positioning information to the designated mobile phone through serial port 2. The software is programmed by modularization, which is divided into main program (main.
c), GPS module (GPS. c), GSM module (GSM. c), LCD module (LCD. c) and display program (display. c). When the main program runs, it calls the variables and function segments defined by calling the variables and function names declared in the header file. The program sets the initialization program of serial port L and serial port 2 respectively. Both serial ports are set to baud rate 960. Serial port 2 uses independent baud rate generator. And the priority of serial port 2 is higher than that of serial port L. The anti-loss system for the elderly and children based on single-chip computer, combined with satellite positioning technology, radio mobile communication technology and signal processing technology, is realized through the design and manufacture of software and hardware.
The design meets the needs of the times, and has a wide application prospect in many fields. It can be used in conjunction with many industries. The device can realize long-distance positioning. Reliability is better, stability is higher, and the production cost is low, cost performance is high, the product is processed again, shape design, increase user experience, in line with the trend of the times, will increase its market circulation.