What is the principle of the lock?

1. Doesn't 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, and the other side is a row of small holes. Inside the small holes are copper pillars and springs of different lengths (the copper pillar is on the side near the key). . Normally, the copper pillar popped out halfway because of no force, which blocked the rotation of the big copper core. When inserted with the corresponding key, the copper column and the teeth on the key contact to form a regular curve, and the gap on the large copper core is flashed to enable it to rotate. The principle of turning to open the lock is relatively simple.

2. In the field of security technology prevention, the electronic combination lock with anti-theft alarm function replaces the traditional mechanical combination lock, which overcomes the shortcomings of the mechanical combination lock with a small amount of passwords and poor security performance, making the combination lock both 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, intelligent combination locks with microprocessors have emerged. In addition to the functions of electronic combination locks, intelligent management and expert analysis systems have also been introduced. Therefore, the combination lock has high security and reliability, and is widely used. This article introduces the intelligent combination lock with 51 series single-chip microcomputer as the core, and expounds its working principle, basic functional block diagram, key design technology and software workflow in detail.

1 Basic principle and hardware composition
The system of intelligent combination lock is composed of intelligent monitor and electronic lock. The two are placed in different places, and the intelligent monitor supplies the power required by the electronic lock and receives the alarm information and status information sent by it. Here, line multiplexing technology is used to make the power supply and information transmission share a two-core cable, which improves the reliability and safety of the system.

1.1 Basic principle and block diagram of intelligent monitor
A block diagram of the composition of the intelligent monitor, which is composed of a single-chip computer, clock, keyboard, LCD display, memory, demodulator, line multiplexing and monitoring, A / D conversion, buzzer and other units. Mainly complete the communication with the electronic lock, intelligent analysis and safety monitoring of the communication line.

The intelligent monitor is always in the receiving state, and receives the alarm information and status information from the electronic lock in a fixed format. For the alarm information, an audible and visual alarm will be issued immediately through the LCD display and buzzer; for the status information, it will be stored in the memory and compared with the historical status of the electronic lock before this time to obtain the change trend and predict the future When the status changes, provide corresponding information to the staff on duty through the LCD display for decision-making use. While the intelligent monitor establishes communication contact with the electronic lock, it monitors the changes of the power supply current flowing through the communication line in real time through the A / D converter, effectively preventing the damage caused by human factors, and ensuring the smoothness of the communication line.

1.2 Basic principle and composition block diagram of electronic lock
The block diagram of the electronic lock. It is also based on the 51 series single-chip microcomputer (AT89051) and is equipped with corresponding hardware circuits to complete the password setting, storage, identification and display, drive the electromagnetic actuator and detect its drive current value, receive the sensor to send Alarm signal, data sending, etc.

The MCU receives the entered 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, which can be entered up to three times; If it is not correct, the MCU will alarm the intelligent monitor through the communication line. The single-chip microcomputer sends each unlocking operation and the drive current value of the electromagnetic actuator as status information to the intelligent monitor, and at the same time sends the alarm information received from the sensor interface to the intelligent monitor as a basis for intelligent analysis.

2 key technologies
In order to improve the security and reliability of the smart combination lock, in addition to taking measures on device selection (such as the use of low power consumption and wide temperature range devices), some key technologies are also used in the design.