The simplest combination lock, common in bicycle locks with low security settings, uses multiple dials. There is a groove in the middle of each circle. There are several protruding teeth on the shaft in the center of the lock to catch the moving ring. When the dial is turned to the correct password combination, the lock can be opened. This lock is the easiest to open. Many of these locks can be opened without knowing the password at all. Unless its internal parts are perfectly made, as long as the axis is pulled out, one of the teeth will tighten the disc ring more than the other. At this point, turn the tightened dial until a small "click" sound is heard, indicating that the teeth have entered the correct groove. Repeat this step, and you will soon be able to open the lock.
Single turntable
The combination lock used in padlocks or boxes can only have one turntable. The turntable pushes several balance disks or cams at the back. It is customary to turn the dial clockwise to the first digit, then counterclockwise to the second digit, and so on until the last digit. There is usually a groove on the cam. When the correct password is entered, when all the bits are in a line, the lock can be opened.
This cipher lock is relatively safe, but it is not without its shortcomings. For example, some password padlocks can pull the lock head and then turn the turntable until it can't move any more, so that the password can be found out. The numbers of some dialing locks also have a specific relationship, which greatly reduces the possibility of password combination. Cheap password padlock can be opened without password and with special lining.
The combination lock used in the box has a tight structure. An experienced locksmith can listen carefully to the sound of the cam in the lock with the receiver while turning the turntable to judge the possible password.
Other designs
Some door locks have a numeric keypad, and when they are opened, a series of numbers are entered in sequence. This kind of lock is electronically controlled and is very common in offices. The advantage is that you only need to tell the employee the password, and you don't need to copy the key. However, if someone tells outsiders the password, the lock is useless. Therefore, the password of this password lock needs to be changed frequently.
Principle of dial-type all-mechanical password lock
This is a full-mechanical password lock with a large number of keys, high reliability and no need for electronic devices. It operates in a unique way, similar to the old-fashioned telephone dialing-starting from the starting point of dialing, turning clockwise to dial a certain number, and then returning to the starting point, you enter the password. Repeat this operation until the last password is entered, and then turn the dial counterclockwise from the starting point to unlock it. At the same time of unlocking, the inside has been reset, so after the dial is turned back to the starting point to lock, you must re-enter the password to unlock it, without considering the internal reset problem. If you enter the wrong password, you can also reset it internally by turning the dial counterclockwise (virtual unlocking), and then re-enter the password.
In this password lock, the six-digit password can have more than 2.98 million groups of passwords for the owner to change at will, which is extremely confidential. Optional password groups are arranged continuously, which provides convenience for selecting passwords that are easy to remember. The basic products that have been developed at present can be redesigned according to the needs of users. You can also add an alarm interface for users.
Advantages of this code lock: 1, no key, no power supply, no battery and no waste pollutants. 2, full mechanical structure, can withstand the harsh external environment, and a wide range of applications. 3. The operation is simple, the unlocking time is relatively short, and the average unlocking time is about 15 seconds. 4. The actual password is large and confidential, and the probability of trying to unlock it is almost zero. 5. Simple structure, firmness and reliability.
According to the law of technological development in history, in the case of similar functions, simple and reliable things will always replace complex things and replace complex and simple things. Therefore, it is a popular and practical new product, which should replace the traditional disc mechanical code lock and some electronic code locks.
The invention is widely used in safes, safes, filing cabinets, antimagnetic fire cabinets, security doors, vault doors, automobile doors, civil doors and mechanical locking mechanisms. It can replace the existing traditional disc mechanical coded locks and some electronic coded locks. It provides an opportunity for the upgrading of some products.
Due to the popularity of electronic technology, many products are proud of adopting electronic structure. However, in some places, electronic products are not absolutely dominant, but mechanical products or electromechanical mixed products are more practical. Give two examples: one is the ignition device of gas stove. The igniter of the early transistor was all the rage, but it was not resistant to moisture, easy to be damaged and inseparable from the battery. Over time, it was replaced by a mechanical (piezoelectric) igniter that stored energy by twisting the knob by hand, which showed its superiority-simple and practical, and became the mainstream of gas stove igniter. Second, car rearview mirrors and bus rear door peepers (single rooms) are in danger of being replaced by electronic monitors, but people find that the observation effect of traditional rearview mirrors and ordinary rearview mirrors above bus drivers is not worse than that of electronic monitors, which is simpler and more practical.
In fact, in traditional industries, we can also find a safer investment direction than the so-called "new economy" but the profit is not inferior. Password lock is not a frequently used product, but a semi-static product, which is more practical by mechanical means. However, due to the large number of passwords in electronic mode, people will feel safer subjectively. The password of the patented product is close to that of the electronic password lock, and the operation is much faster than that of the traditional mechanical password lock, which is simple and practical and can be expected to become the mainstream of high-grade password locks like the above two situations.
Working principle of intelligent password lock
The basic principle and hardware composition of 1
Intelligent password lock system consists of intelligent monitor and electronic lock. The two are placed in different places, and the intelligent monitor provides the power needed by the electronic lock and receives the alarm information and status information sent by it. In this paper, line multiplexing technology is used to make a two-core cable used for power supply and information transmission, which improves the reliability and security of the system.
1. 1 Basic principle and composition block diagram of intelligent monitor.
The composition block diagram of intelligent monitor is composed of single chip microcomputer, clock, keyboard, liquid crystal display, memory, demodulator, line multiplexing and monitoring, A/D conversion, buzzer and other units. It mainly completes the functions of communication with electronic lock, intelligent analysis, communication line safety monitoring and so on.
At the sending end, the electronic lock boosts the modulated data signal through the pulse transformer T and sends it out; At the receiving end, the pulse transformer T reduces the voltage of the received data signal and sends it to the demodulator to reduce the loss of the carrier signal in the transmission process. In order to reduce the interference between communication and power supply, the choice of choke L and coupling capacitor C should be considered comprehensively.
Let the carrier frequency fo = 400 kHz and l = 33.7 μ h to ensure that most of the signal energy is transmitted to the receiving end. C 1=0.047 microfarad.
2.2 Current monitoring technology
In order to prevent the communication line from being destroyed and the electromagnetic actuator from burning the coil due to excessive current flowing in the electromagnetic coil for some reason, the current monitoring technology is adopted in the design of intelligent password lock. The current monitor adopts the current/voltage conversion chip MAX47 1 produced by MAXIM company. The chip can convert the measured current I into the ground output voltage U, which has the characteristics of large measurement range and high precision. The output voltage U is proportional to the measured current I, and the output voltage of the current monitor is sent to the A/D converter. By reading the result of A/D conversion, the single chip microcomputer can know the change of current in the line, find the abnormality in time through analysis, and send out an alarm signal.
2.3 Data communication and preprocessing technology
The intelligent monitor receives the status information sent by the lock (including lock opening and closing, first password error, second password error, third password error, etc.). ) and the current value flowing through the electromagnetic actuator coil, and read the power supply current value of the communication line at this time, which are combined to form a data block, in which the running state accounts for 1 byte, the power supply current accounts for 2 bytes, and the coil current accounts for 2 bytes. The intelligent monitor is always in the receiving state during the communication with the electronic lock. In order to improve the reliability of communication, this paper adopts the method of repeated transmission in the communication protocol. The electronic lock repeatedly sends each set of data five times. After receiving this set of data, the intelligent monitor adopts large number decoding method to correct errors, which ensures the accuracy of data reception. In addition, in order to save memory, the received data should be preprocessed, that is, after each data is received, it should be compared with the set threshold, and if it is greater than the threshold, it will send out an overrun alarm; If it is less than the threshold, compare the data with similar data received on the same day and keep the larger one. In this way, the data stored every day is the largest of its kind,
2.4 Intelligent analysis
Intelligent analysis and prediction technology is based on each received data block, compared with the previously recorded similar data values, to analyze the current changes and trends caused by this operation, find existing problems in time, and report them to managers, thus improving the reliability of the whole system.
3 system software design
The intelligent password lock software uses 5 1 series single chip microcomputer assembly language to program the intelligent monitor and the electronic lock respectively. Intelligent monitoring software includes keyboard scanning and LCD display program, buzzer driver program, clock modification and reading program, data communication and preprocessing program, intelligent analysis program and line monitoring program. The electronic lock software includes keyboard scanning and decoding program, liquid crystal display program, communication program, electromagnetic actuator driving and detection program, sensor interface program and other modules. Modular design method is adopted in the process of software design, which is convenient for reading, debugging and perfecting the program.
Intelligent password lock makes full use of the software and hardware resources of 5 1 system single chip microcomputer and introduces intelligent analysis function, which improves the reliability and security of the system. The system has been installed and used in a certain type of safe and is welcomed by users. In addition, the intelligent password lock can form an intelligent distributed monitoring network by slightly changing the software and hardware, which can realize centralized monitoring and management in a certain range, and has a wide application prospect in the fields of finance, insurance, military and other security precautions.
The intelligent monitor is always in the receiving state, receiving the alarm information and status information in fixed format sent by the electronic lock. For the alarm information, an audible and visual alarm will be given immediately through the LCD and buzzer; The state information is stored in the memory, compared with the historical state of the electronic lock before this moment, the change trend is obtained, the future state change is predicted, and the corresponding information is provided to the personnel on duty for decision-making through the LCD. When the intelligent monitor establishes communication with the electronic lock, it monitors the change of power supply current flowing through the communication line in real time through the A/D converter, which effectively prevents the damage caused by human factors and ensures the smooth communication line.
Basic principle and composition block diagram of 1.2 electronic lock
The block diagram of the electronic lock is also based on the 5 1 series single-chip microcomputer (AT8905 1), which cooperates with the corresponding hardware circuit to complete the functions of password setting, storage, identification and display, driving the electromagnetic actuator, detecting its driving current value, receiving sensor alarm signals, sending data and so on.
The MCU receives the typed code and compares it with the password stored in EEPROM. If the password is correct, it will drive 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 it is incorrect for three consecutive times, the single chip microcomputer will alarm the intelligent monitor through the communication line. The single-chip microcomputer sends the driving current value of the electromagnetic actuator and each unlocking operation as state information to the intelligent monitor, and also sends the alarm information received from the sensor interface to the intelligent monitor as the basis for intelligent analysis.
Two key technologies
In order to improve the security and reliability of intelligent password lock, this paper not only takes measures in device selection (such as using devices with low power consumption and wide temperature range), but also adopts some key technologies in design.
2. 1 line multiplexing technology
The intelligent monitor and the electronic lock are placed in different places. The intelligent monitor provides the power needed by the electronic lock and receives the alarm information and status information sent by it. If the communication line and the power supply line are separated, it is bound to increase the number of cable cores and increase security risks. In this paper, line multiplexing technology is adopted, and only one two-core cable is used to realize power supply and information transmission.