First, is there not a copper heart in the ordinary lock? When it is removed, you can see that there is a slot on the top side - - the direction of the back of the key, and a row of small holes on the other side. Inside the holes are different lengths of copper pillars and springs (copper pillars near the key side) sealed with aluminum. Usually the copper column is ejected from the force without force, and it blocks the rotation of the copper core. When inserted with the corresponding key, the copper column contacts the teeth on the key to form a regular curve, and the gap on the large copper core is opened so that it can rotate. And the principle of turning the lock open is relatively simple.
Second, in the field of security technology, electronic password lock with anti-theft alarm function replaces the traditional mechanical password lock, overcomes the shortcomings of mechanical password lock, such as less password, poor security performance, so that the password lock has greatly improved both in technology and performance. With the development of large-scale integrated circuit technology, especially the advent of single-chip microcomputer, intelligent password lock with microprocessor appears. Besides the function of electronic password lock, it also introduces the functions of intelligent management and expert analysis system, so that the password lock has high security, reliability and is used more and more widely. . This paper introduces the intelligent password lock based on 51 series single chip microcomputer, and expounds its working principle, basic function block diagram, key design technology and software workflow in detail.
1, basic principles and hardware components
The system of intelligent cipher lock consists of intelligent monitor and electronic lock. The intelligent monitor supplies the power needed by the electronic lock and receives the alarm and status information. Line multiplexing technology is used here to make the power supply and information transmission share a two-core cable, which improves the reliability and security of the system.
1.1 the basic principle and block diagram of intelligent monitor
The block diagram of intelligent monitor is composed of single chip microcomputer, clock, keyboard, LCD display, memory, demodulator, line multiplexing and monitoring, A/D conversion, buzzer and other units. Mainly complete the communication with electronic locks, intelligent analysis and communication line safety monitoring and other functions.
The intelligent monitor is always in the receiving state, receiving the alarm information and status information from the electronic lock in a fixed format. For alarm information, sound and light alarm will be issued immediately through LCD display and buzzer; for status information, it will be stored in memory, and compared with the historical state of electronic locks before this time, the change trend can be obtained, the future state change can be predicted, and the corresponding information can be provided to the staff on duty through LCD display. For decision making. Intelligent monitor and electronic lock establish communication links at the same time, through the A / D converter real-time monitoring of power supply current changes across the communication line, effectively prevent damage caused by human factors, to ensure the smooth communication line.
1.2 the basic principle and block diagram of electronic locks
The block diagram of the electronic lock is also based on the 51 series single chip microcomputer (AT89051) as the core, with the corresponding hardware circuit, to complete the password settings, storage, identification and display, drive the electromagnetic actuator and detect its driving current value, receive the alarm signal sent by the sensor, send data and other functions.
The MCU receives the input code and compares it with the password stored in EEPROM. If the password is correct, it drives the electromagnetic actuator to unlock. If the password is incorrect, the operator is allowed to re-enter the password for up to three times. If the three times are incorrect, the MCU directs the intelligent monitoring through the communication line. Alarm. The SCM sends the status information of each unlocking operation and the driving current value of the electromagnetic actuator as the status information to the intelligent monitor, and sends the alarm information from the sensor interface to the intelligent monitor as the basis of intelligent analysis.
2, key technologies
In order to improve the security and reliability of the intelligent password lock, some key technologies are adopted in the design, besides the device selection, such as low power consumption and wide temperature range devices.
2.1 line multiplexing technology
Intelligent monitors and electronic locks are placed in different places. Intelligent monitors supply the power needed by electronic locks and receive the alarm information and status information sent by them. If the communication line and power supply line are separated, the number of cable cores must be increased, and the potential safety hazards will be increased. In this paper, line multiplexing technology is used, and only one two core cable is used to achieve the transmission of power supply and information.