I believe that everyone has the experience of forgetting or losing the key, which also brings us a lot of troubles. The progress of science and technology has brought great changes and improvements to our lives. Intelligent door lock is not only the first guarantee for families, but also brings us more convenience. As the hot field of smart home, there are many kinds of smart door locks in the market.
Life is more common, the entrance of the community brush magnetic card door, hotel room doors are used induction locks. Induction lock generally uses various “cards” as the key, which can be divided into contact card and non-contact card. The contact type mainly includes magnetic stripe card and IC card. Unlocking is to put the card into the card slot, which reads the card information and checks whether the card information is consistent with the original data. The contactless type includes TM card and RF card. The TM card uses single line protocol communication, and the RF card uses radio signal identification information. Both of them complete data reading and writing through instantaneous touch, without inserting the card slot and using the card reader.
At present, the contact card technology is mature and the price is low, but long-term use will lead to magnetic stripe damage; the non-contact card is easy to use, and can be authorized by computer, which is more convenient for management, and has a great potential to catch up.
No matter contact card or non-contact card, there is a disadvantage, which can’t be forgotten or lost. For mobile phone with NFC function, by reading the information of access card, virtual door key can be added to solve the problem of forgotten or lost.
Digital code lock
Use your fingers to input and click the corresponding digital password on the electronic display screen, and then access the control system to control the closing of the mechanical switch. The access control system is realized by the control circuit. Taking at89051 as an example, which is commonly used in the electronic password lock, the corresponding hardware circuit is used to complete the function of password setting, storage and identification. When the user clicks on the LCD, the SCM receives the current change from the sensor, and compares it with the password stored in EEPROM through a / D conversion. If the password is correct, it will drive the electromagnetic to unlock the lock. If it is not correct, it will input again.
The price of password lock is more expensive than traditional key lock, but it can solve the problem of key forgetting and losing, and avoid the problem of “clone” after the key is picked up by others. The password can be modified and the security is guaranteed. However, when using the electronic password lock, it is necessary to pay attention to that the frequently used key position will leave traces. It is better to wipe the display screen or change the password frequently.
Biometric smart lock
Biometric intelligent lock is the highest level of intelligent door lock, including fingerprint, iris, face. At present, fingerprint lock is the most widely used in the market.
Fingerprint identification is mainly divided into two types: optical fingerprint lock and semiconductor fingerprint lock. Semiconductor fingerprint lock uses capacitance. Most fingerprint identifiers on the market use capacitive touch technology. Semiconductor fingerprint identification device is divided into two parts. Hardware includes semiconductor device (sensor), processing chip and storage chip. The core of software is algorithm.
The combination of software and hardware, different modules perform their own duties, using the potential difference of the concave and convex finger lines induced by capacitance, the processing chip is responsible for calculating and judging the obtained pictures or features, and the storage chip is responsible for storing relevant data and algorithms. The quality of the sensor determines the accuracy of the recognition on the hardware level; the processor as the “central part” determines the speed and power consumption of the algorithm. The input fingerprint is processed by the algorithm to improve the accuracy of the recognition. In the subsequent unlocking process, features and image matching are needed; the amount of data stored depends on the memory. In fact, this unlocking method is not new to us. Now the popular mobile fingerprint unlocking is the principle used. Although fingerprint lock is a product with high security, there are some problems. For example, when the fingers are damaged, they cannot be well identified.
No matter what kind of identification method is adopted, such as access card identification, password identification, fingerprint identification, etc., its working principle is the same, which is to convert the collected information into images and feature points, and then compare them with the images and feature points stored in the chip.