First, does the ordinary lock have a copper heart? After disassembling, you can see that the upper side is the slot---the direction of the key back, the other side is a row of small holes, the small holes are the lengths of the copper posts and the springs (the copper posts are close to the key side) and the aluminum seals are used outside. . Usually the copper column pops out half because it is not force, and blocks the rotation of the big copper heart. When inserted with the corresponding key, the copper post contacts the teeth on the key to form a regular curve, which flashes the gap on the large copper core to enable it to rotate. The principle of turning the lock open is relatively simple.
Second, in the field of security technology prevention, the electronic password lock with anti-theft alarm function replaces the traditional mechanical password lock, which overcomes the shortcomings of mechanical password lock password and poor security performance, making the password lock technically and in performance. Both have greatly improved one step. With the development of large-scale integrated circuit technology, especially the advent of single-chip microcomputers, there has been a smart password lock with a microprocessor. In addition to the function of electronic password lock, it also introduces functions such as intelligent management and expert analysis system. Therefore, the password lock has high security and reliability, and the application is increasingly widespread. This paper introduces the intelligent password lock with 51 series single chip as the core, and elaborates its working principle, basic functional block diagram, key design technology and software workflow.
1, the basic principle and hardware
systems intelligent locks by intelligent monitoring and electronic locks with composition. The two are placed off-site, and the smart monitor supplies the power required by the electronic lock and receives the alarm information and status information sent by it. Here, the line multiplexing technology is adopted to share a two-core cable for power supply and information transmission, which improves the reliability and safety of the system.
1.1 The basic principle and composition block diagram of the
intelligent monitor The block diagram of the intelligent monitor consists of a single chip microcomputer, clock, keyboard, LCD display, memory, demodulator, line multiplexing and monitoring, A/D conversion, buzzer The composition of the unit. The main complete with electronic locks communications, intelligence analysis and security monitoring functions such as communication lines between the tools.
The intelligent monitor is always in the receiving state, receiving alarm information and status information from the electronic lock in a fixed format. For the alarm information, the sound and light alarms are immediately sent through the LCD display and the buzzer; for the status information, it is stored in the memory and compared with the historical state of the electronic lock before this time, and the trend is changed to predict the future. The status changes, and the corresponding information is provided to the duty officer through the LCD display for decision making. While the intelligent monitor establishes communication with the electronic lock, the A/D converter monitors the change of the supply current flowing through the communication line in real time, effectively preventing the damage caused by human factors and ensuring the smooth communication line.
1.2 The basic principle and composition of the
electronic locks The block diagram of the electronic locks is also based on the 51 series single-chip microcomputer (AT89051), with the corresponding hardware circuit, complete the setting, storage, identification and display of the password, drive the electromagnetic actuator and detect It drives the current value, receives the alarm signal from the sensor, and sends data.
The MCU receives the typed code and compares it with the password stored in the EEPROM. If the password is correct, the electromagnetic actuator is unlocked; if the password is incorrect, the operator is allowed to re-enter the password, up to three times; if three times If it is not correct, the MCU will alarm the intelligent monitor through the communication line. The single-chip microcomputer sends the unlocking operation and the driving current value of the electromagnetic actuator as the status information to the intelligent monitor at this time, and also sends the alarm information received from the sensor interface to the intelligent monitor as the basis of the intelligent analysis.
2. Key Technologies
In order to improve the security and reliability of smart password locks, in addition to taking measures on device selection (such as devices with low power consumption and wide temperature range), some key technologies are also adopted in the design.
2.1 line multiplexing technology
intelligent monitor and electronic lockPlaced off-site, the smart monitor supplies the power required by the electronic lock and receives the alarm and status messages it sends. If the communication line and the power supply line are separated, it is necessary to increase the number of cable cores and increase the safety hazard. This paper adopts the line multiplexing technology, which uses only one two-core cable to realize the transmission of power and information.