Smart lock concept

Smart Lock (Intelligent Lock) is a kind of lock that is different from traditional mechanical locks in terms of user identification, security, and management. A smart lock is an executing component of a door lock in an access control system.

Today's smart locks are different from the previous "open and re-scan" method. The scanning method is very simple. Place your finger over the top of the scan to scan from top to bottom without pressing your finger at the scan. Reduce the number of fingerprints, greatly reduce the possibility of fingerprints being copied, and securely enjoy the exclusive use.

Introduction

Smart lock refers to a lock that is different from a traditional mechanical lock and is more intelligent in terms of user identification, security, and management, and an execution part of a door lock system.

The smart lock is different from the traditional mechanical lock and is a complex type lock with safety, convenience, and advanced technology.

Mature technologies that use non-mechanical keys as user IDs, such as:

Fingerprint lock, iris recognition access control (biometrics, high security, no loss of damage; but inconvenient configuration, high cost)

Magnetic card, radio frequency card (non-contact type, high security, plastic material, easy to carry, low cost)

TM card (contact type, high safety, stainless steel, extremely easy to carry, low price)

More applications in the following places: banks, government departments (focus on safety), and hotels, school dormitories, residential communities (focus on convenient management)

Features

Convenience (a) The smart lock is distinguished from a general mechanical lock with an automatic electronic sensor locking system. It automatically senses that the system will automatically lock when the door is closed. The smart lock can unlock the door lock through the fingerprint, touch screen, and card.

b. In general, fingerprint locks are inconvenient when using functions such as password/fingerprint registration. Especially when the elderly and children use the smart locks, they can turn on their unique voice prompts to make the operation easier and easier for the user.

Safety a. The general fingerprint code lock has the danger of password leakage. The recent smart lock also has a virtual bit cryptographic function technology, that is, in front of or behind the registered password, any number can be input as a virtual bit password, which effectively prevents the registration password from leaking, and at the same time can unlock the door lock. b. In the ordinary residential security environment, the general door lock handle opening method can not ensure sufficient safety performance, it is very easy to drill the hole from the outside of the door and then use the wire to turn the handle to open the door. Many smart locks are protected by patented technology. The safety handle buttons have been added to the handlebar settings in the room. You need to press and hold the safety handle button to turn the handle door to open it, which leads to a safer use environment. (At the same time, according to the user's needs, this function can be selectively set by simple operation.) c. The smart lock of the most recent touch screen will be displayed automatically, and it will automatically lock in 3 minutes. Whether the password has been set, whether the door lock has been opened or closed, the number of password or door card registration, the battery replacement prompt, the lock tongue blocking warning, low voltage, etc., all displayed on the screen, intelligent intelligent control.

Security The recent smart lock is different from the previous “open and rescan” method. The scanning method is very simple. Place your finger on top of the scan to scan from top to bottom without pressing your finger on the scan. At the same time, the scanning method will reduce the fingerprint residue, greatly reducing the possibility of fingerprints being copied, and securing the exclusive use.

Creative Traditional mechanical locks are not particularly concerned with its appearance. The smart lock not only adapts to the people's taste from the appearance design, but also creates a smart lock that resembles an apple. Intelligent locks have been quietly on the market.

The interactive intelligent door lock has built-in embedded processor and intelligent monitoring system. It has the ability to interact with the tenant at any time and can report the visitors of the TV on the day. On the Other hand, visitors can even remotely control the smart door lock to open the door for visiting guests.

Technical principle

The basic principle of folding

The smart password lock system consists of a smart monitor and an electronic lock. The two are placed off-site, and the intelligent monitor supplies the power required by the electronic lock and receives the alarm information and status information it sends. Here, line reuse technology is used to make the power supply and information transmission share a two-core cable, which improves the reliability and security of the system.

1.1 Basic Principles of Smart Monitor

The intelligent monitor consists of a single-chip microcomputer, clock, keyboard, LCD display, memory, demodulator, line multiplexing and monitoring, A/D conversion, buzzer and other units. It mainly completes the communication with the electronic locks, intelligent analysis, and the safety monitoring of communication lines.

The intelligent monitor is always in the receiving state and receives the alarm information and status information sent by the electronic lock in a fixed format. For alarm information, sound and light alarms are immediately sent through the LCD display and buzzer; for status information, they are stored in memory and compared with the historical state of the electronic lock before this time, and the change trend is predicted to predict the future. Changes in status, through the LCD display to the duty staff to provide appropriate information for decision-making use. The intelligent monitor establishes communication with the electronic lock and simultaneously monitors the change of the supply current flowing through the communication line in real time through the A/D converter, thereby effectively preventing damage caused by human factors and ensuring the smoothness of the communication line.

1.2 The basic principle of electronic locks

The electronic lock is also based on the 51 series single chip microcomputer and is equipped with corresponding hardware circuits to complete the setting, storage, identification and display of the password, drive the electromagnetic actuator and detect its driving current value, receive the alarm signal sent from the sensor, and send data. Other functions.

The microcontroller accepts 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, up to three times; if three times If not, the microcontroller will alert the smart monitor via the communication line. The single-chip microcomputer sends each time the unlocking operation and the drive current value of the electromagnetic actuator as status information to the intelligent monitor, and simultaneously sends the alarm information received from the sensor interface to the intelligent monitor as a basis for intelligent analysis.

Folding key technologies

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

2.1 Line Multiplexing Technology

Intelligent monitors and electronic locks are placed off-site. If the method of separating the communication line from the power supply line is used, the number of cable cores is bound to increase, and the potential safety risks increase. In this paper, line reuse technology is used, and only one two-core cable is used to achieve power supply and information transmission. The schematic is shown in Figure 3.

At the sending end, the electronic lock is used to boost the modulated data signal by pulse transformer T and send it out. At the receiving end, the pulse transformer T steps down the received data signal and sends it to the demodulator to reduce the carrier signal during transmission. Loss in the. In order to reduce mutual interference between communication and power supply, the selection of choke coil L and coupling capacitor C should be considered comprehensively.

Let the carrier frequency fo = 400kHz, in order to ensure that most of the signal energy is transmitted to the receiving end, take L = 33.7μH?C1 = 0.047μF.

2.2 Current Monitoring Technology

In order to prevent the man-made destruction of the communication line and the electromagnetic actuator for some reason caused the current flowing through the electromagnetic coil is too large to burn the coil, the current monitoring technology is adopted in the design of the intelligent code lock.

2.3 Data Communication and Preprocessing Technology

The intelligent monitor receives the status information sent by the lock (including the opening and closing of the lock, the first password error, the second password error, the third password error, etc.), the current value flowing through the electromagnetic actuator coil, and Read the current value of the power supply of the communication line at the moment, the three combine to form a data block, in which the operating state occupies 1 byte, the supply current occupies 2 bytes, and the coil current occupies 2 bytes. The smart monitor is always in the receiving state during communication with the electronic lock. In order to improve the communication reliability, this article adopts the repeated transmission method in the communication protocol. The electronic locks repeatedly send data for each group of data 5 times. After the intelligent monitor receives this group of data, it adopts the law of large number decoding to correct errors and ensure the The accuracy of data reception. In addition, in order to save memory, the received data must be preprocessed. That is, after each data is received, the data is first compared with the set threshold. If it is greater than the threshold, an over-limit alarm is issued; if less than The threshold value is compared with the same type of data received on that day, and the larger one is reserved. This way, the data stored every day is the maximum value of the same kind of data.

2.4 Intelligent Analysis

The intelligent analysis and prediction technology is based on the data block received each time, and compared with the record value of the previous similar data, analyzes the magnitude and trend of the current change caused by the operation, discovers the problem in time, and reports the management personnel. Improve the reliability of the entire system.

system software

The smart password lock software uses the 51 series microcontroller assembly language to program the smart monitor and the electronic lock separately. Intelligent monitor software includes keyboard scanning and LCD display programs, buzzer driver, clock modification and reading programs, data communication and preprocessing programs, intelligent analysis programs, and line monitoring programs. The electronic lock software includes keyboard scanning and decoding programs, LCD display programs, communication programs, electromagnetic actuator driving and testing programs, and sensor interface programs. The modular design method is used in the software design process to facilitate the reading, debugging and improvement of the program.

The intelligent password lock makes full use of 51 system microcontroller's software and hardware resources, and introduces intelligent analysis functions to improve the system's reliability and security. Through the use of a certain type of safe installation, it is welcomed by users. In addition, the intelligent password lock is slightly modified in terms of software and hardware to form an intelligent distributed monitoring network to achieve a centralized monitoring and management within a certain range, and has a wide range of applications in the fields of finance, insurance, military heavy equipment, and other security. Application prospects.

Smart lock common types

3.1 Remote locking of the classification of smart locks

Current common remote control locks are mainly light remote control (remote control, etc.) and radio remote control (Bluetooth, etc.).

3.2 code lock of smart lock category classification

At present, there are keyboard-type electronic password locks and touch-sensitive keyboard password locks. The former is widely used and contrasts texture buttons. The latter is the more beautiful LED touch screen. Today, the development of the use of merit is praiseworthy. It can set up multiple digit passwords, can be changed arbitrarily, can participate in irregular numbers to maintain passwords, and passwords can be mistyped three times to lock up for a certain period of time.

3.3 Card locks for smart lock category classification

The use of various cards instead of keys for swiping cards to open doors is more widely used nowadays. There are more employees in the company, access to the community, transportation, etc., and they can even use more than one card, open the door, ride a car, spend, and so on. However, the use of proximity card locks is similar to that of remote-controlled smart locks. It is necessary to keep the magnetic cards well and lose the need to revoke the card's authorization.

3.4 Smart Locks Category Biometric Anti-theft Lock

Because biometric skills develop rapidly, human fingerprints, eyes, sounds, and other features that cannot be repeated are used as vectors to open doors. Common fingerprint locks, face recognition locks, voice locks, and so on. The advantage is that the "key" is carried around by itself, and the security is even higher. It is loved and sought after by high-end users.

Of course, skill innovation is increasingly sophisticated, and the types of smart locks used are endless. Many product sets have multiple functions. They can be turned on remotely, can be turned on by password, can be opened by swiping cards, can be opened by fingerprints, and active anti-lock and aggression alerts are also necessary humanity. The function is more reliable in terms of security. However, from the smart lock itself, its performance is sometimes still unstable. (Electronic lock), for example, encounters harsh environments such as high temperature and strong magnetic shock, some smart locks may fail, fingerprint lock fingerprint reader service life and many more.

With the development of technology, there will inevitably be more locks, such as emerging voiceprint locks, face recognition locks, iris locks and so on.