Design of the latest intelligent anti-theft system

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Design of a new type of intelligent anti-theft system for automatic photographing

at present, the anti-theft devices on the market can be roughly divided into alarm type and microcomputer monitoring type. The alarm type anti-theft system is cheap and simple in structure, but its function is only a simple alarm, and thieves can still escape. The system cannot leave effective legal evidence. It is precisely because of its invalidity that hinders the expansion of its market. The other is the microcomputer monitoring type. This device is more advanced, but its cost is high. It must work under the support of 220V voltage, and it needs some technical personnel to operate it

this system mainly combines the disadvantages of these two devices, applies infrared technology and the principle of single chip microcomputer, and applies the camera to the anti-theft system. It has the characteristics of economy, science and efficiency, especially suitable for anti-theft of rural animal husbandry

infrared ray has certain penetrability, and the earth's atmosphere has obvious selectivity in the absorption of infrared radiation, of which 1 ~ 2.5 μ m、3~5 μ m、8~14 μ M three atmospheric windows are particularly important in infrared technology. The appropriate infrared radiation source, receiver and working distance should be selected according to the working wavelength of infrared

LPC900 Series MCU is a high-speed, low-power flash MCU based on 80C51 core, which mainly integrates a series of distinctive functional components such as I2C bus, SPI interface, UART communication interface, real-time clock, EEPROM, a/d converter, ips/iap programming and remote mode. P89LPC932 is one of the series. It adopts a high-performance processor structure, and the instruction execution time only needs 2 ~ 4 clock cycles. It integrates many system level functions, which can greatly reduce the number of components and circuit board area and reduce the cost of the system. It is suitable for many occasions requiring high integration and low cost, and can meet various performance requirements. It is used to perform control functions in this system

composition of the system

the material properties produced are also very high-end

the intelligent anti-theft system uses infrared light-emitting diode as the signal source, photosensitive triode as the infrared receiving device, adopts lens focusing technology to improve the sensitivity and anti-interference ability of the system, and uses analog electronic circuit to amplify the signal in the process of signal processing, in order to eliminate the phenomenon of false alarm and photographing when other small animals pass by, The single chip microcomputer is used as the control machine to collect, process and control the signal, which can effectively eliminate the interference and improve the accuracy of the system. At the same time, in order to prevent the system itself from being damaged, the drive circuit of alarm and electric light is also equipped in the design, so that the structure of the alarm is more reasonable and the function is more perfect

working principle of the system

this device uses the photoelectric conversion principle to convert electrical signals into optical signals. The core device that converts electrical signals into optical signals is three infrared light-emitting diodes, which add a fixed voltage at both ends to produce a continuous optical signal. The infrared receiving device is realized by photosensitive triode, so that the infrared light emitted by the infrared light-emitting diode can be converted into an electrical signal. However, because the electrical signal at this time is weak, it is not enough to drive the circuit and load to work normally, so the analog amplification circuit is used to amplify the signal, so that it can ensure the following circuit and load to work normally

due to the limited effective working distance of the infrared transmitting device and the infrared receiving device, the lead screw and the lead nut as the performing parts must minimize the loss of light source energy. In order to maximize the light source energy of the led to be received by the photosensitive triode, the through lens focusing technology is adopted to realize, so that the working distance can reach 8 ~ 9m, or even further, At the same time, a special circuit is used to solve the phenomenon of system false beat and false alarm caused by small animals passing by. People are the direct cause of the automatic camera alarm of the system. When at least two beams of light are blocked, the system will alarm, effectively eliminating the interference of other small animals and improving the accuracy of the system. When the system detects abnormal conditions, it will send an alarm and trigger the camera to take pictures at the same time. The device is also equipped with a user-defined function expansion interface, which can be set to automatically dial 110, or set all the lights in the home to be turned on

software design

the software design of the system is mainly the single-chip microcomputer program design, which adopts high-level language in scientific calculation and assembly language in real-time control. Single chip microcomputer is often used for real-time control, while automatic control is often real-time control. This system uses the real-time control function of single chip microcomputer to carry out real-time monitoring on the scene and real-time control of cameras, alarms and other devices

among them, the single-chip microcomputer program design should complete the data collection, the system's self-test, self calibration function and signal collection, and determine whether to take photos and alarm

single chip microcomputer adopts pl/m-96 language programming, which is characterized by the advantages of high-level language and assembly language at the same time. It can directly use the hardware characteristics of different CPU materials requiring different test speeds for program design. Pl/m-96 language programming block has good readability, high reliability and high quality of code conversion


this system successfully introduces the camera into the anti-theft system, develops and forms a solid shape after the closed space, designs the special circuit of the system, realizes the two out of three alarm, eliminates the interference of other animals, integrates the functions of single chip microcomputer, digital electronic circuit and analog electronic circuit technology, and applies infrared technology and camera principle at the same time, so that the system has low price The structure is simple and practical

the system has low power consumption and can work normally under a voltage of more than ten volts without the support of lighting circuit. The temperature change has little impact on the system, especially in places with large temperature difference in the north

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