Fingerprint recognition bluetooth smart car lock design

With the rapid development of my country's economy, people's lives have reached a well-off level, and cars have gradually been widely used as a means of transportation. Along with increasing quantity of automobile in society, the safety problem of automobile is more and more serious, and automobile theft case often takes place. Car door locks, as the first barrier to prevent car theft, can be said to be the top priority in car safety. In order to solve the safety problem of car door locks, some models use car fingerprint recognition technology to improve the safety factor of car doors.

However, the current automotive fingerprint recognition systems are all mounted on the car door, and the driver must reach out and touch the fingerprint recognition system on the car door to unlock it. Compared with the existing remote control unlocking, this is not easy, and most of the current car fingerprint recognition systems are only equipped on high-end models, and seldom equipped on ordinary models, which means that the security problems of most car door locks are still unsolved. Today, many electronic products, including smart phones, have used fingerprint recognition as a major selling point. Therefore, it has become an inevitable trend in the development of the automobile lock system to combine the high-safety fingerprint recognition technology with the Bluetooth technology that can transmit data at an appropriate distance.

In order to solve the problem of car door lock security, this paper designs a Bluetooth car lock system based on fingerprint recognition. It combines the bluetooth module with the fingerprint identification module through the single chip microcomputer, so that the fingerprint identification system can be carried around and used at a long distance, which improves the convenience of the system. In addition, the system adopts the fingerprint unlocking method, which is more reliable than the traditional unlocking method. At the same time, it can also ensure that the car lock will not be opened by others after the key is lost or stolen, and the safety performance is greatly enhanced. In addition, the system can be expanded in many aspects to adapt to the characteristics of different environments, provide special application requirements, and have a wider scope of application. After experimental testing, the Bluetooth car lock system based on fingerprint recognition designed in this paper can remotely unlock the door with fingerprint recognition, and its unlocking accuracy within 5 m is as high as 97%.

1. Fingerprint recognition bluetooth car lock design

The bluetooth car lock circuit system based on fingerprint recognition proposed in this paper includes a key with the functions of fingerprint unlocking and sending signals, and a car lock with the function of judging whether to unlock after receiving signals. The key part includes single-chip microcomputer system, HC-05 bluetooth module, fm-608 fingerprint module, 12864 liquid crystal display, 24c02 storage, keyboard and power supply part, etc. The car lock part includes HC-05 Bluetooth module, single-chip microcomputer system, electromagnetic relay, LED indicator light, electromagnetic lock and power supply part, etc. System block diagram, as shown in Figure 1.

The system is mainly divided into two functions, namely the collection and processing of fingerprint signals and the transmission and comparison of verification codes. First, the key part of the system collects and compares the user's fingerprint through the fingerprint recognition module. Then, send different signals to the single-chip microcomputer system according to the result of the comparison. The single-chip microcomputer performs the next step according to the received signal. If the signal of unlocking is allowed, the serial port communication will be started, and the stored check code will be sent to the lock part through the Bluetooth module; if the signal of unlocking is not allowed, the serial port will not work. No verification code is sent. At the same time, the combination alarm system of the key part gives an alarm, indicating that the fingerprint is wrong and the lock cannot be unlocked. If the check code is sent and received successfully, the lock part will compare the received check code with the check code stored inside. If the two are the same, the LED of the lock part will light up, and the connected electromagnetic relay will be started at the same time. The electromagnetic lock is powered on and opened to realize the unlocking function. After a period of delay, the relay is powered off, and the electromagnetic lock is powered off; if the two check codes are different or the check code is not received, the single-chip microcomputer system of the lock part will not control the peripheral equipment, and the electromagnetic relay will not action, always waiting for the arrival of the next signal.

At the same time, in order to prevent fingerprint recognition from being temporarily unavailable due to finger injuries, dirty fingers, or other factors, the article independently adds a password unlocking function, using the keyboard to enter the password. Similar to fingerprint unlocking, if the input password is the same as the password stored in the key, the verification code will be sent, if not, it will not be sent, and the combined alarm system will sound an alarm.

2. Fingerprint Bluetooth car lock hardware design

The system consists of a key part and a car lock part. The key part is composed of FM-608 optical fingerprint identification module, 24c02 memory chip, HC-05 Bluetooth module, 12864 LCD with fonts, buzzer, 5MM red LED and single-chip microcomputer system. This time, the STC89C52 single-chip microcomputer was selected, which has the advantages of large production volume, mature technology and low price. Since the 52 series MCU has only one full-duplex communication serial port, a set of micro switches is used to separate the serial port of the fingerprint recognition module from the Bluetooth module.

The car lock part includes HC-05 Bluetooth module, STC89C52 microcontroller, 5MM red LED, electromagnetic relay and electromagnetic lock. Since the car lock only needs to communicate with the Bluetooth module through the serial port, the serial port of the microcontroller on the car lock does not need to use a micro switch, and is directly connected to the Bluetooth module.

(1) Fingerprint identification module: The system adopts FM-608 series optical fingerprint module. This fingerprint identification module takes high-performance DSP processor as the core, and is composed of optical fingerprint sensor and Flash chip. It has the following advantages:

1) The algorithm is excellent and meets the current highest standards in the fingerprint industry;

2) Sensitive response and strong fingerprint adaptability;

3) The self-learning adaptation function can be customized, and the parameters can be automatically adjusted according to changes in the user's habits and climate to achieve better matching;

4) Specific green LED high-brightness light source, superior anti-aging performance. When the user presses the fingerprint identification module, the module sends an induction signal to the single-chip microcomputer, and after receiving the signal, the single-chip microcomputer system sends an instruction to the fingerprint identification module to start collecting the user's fingerprint. Then image processing is carried out, and the fingerprint feature information is extracted according to the algorithm in the DSP, compared with the stored fingerprint information, and then different signals are sent to the single-chip microcomputer system according to the comparison result. The single-chip microcomputer system selects the next action according to the different signals received. The fingerprint identification module is also responsible for the functions of entering user fingerprints and deleting user fingerprints.

(2) Combined alarm system of light and sound: When the fingerprint identification module finds that the fingerprint is incorrect after query and comparison, the system processes and determines that the fingerprint is wrong, and the combined alarm system starts on the key. At this time, the LED light is off, the buzzer starts, and it emits a piercing sound, indicating that the fingerprint is wrong. This user has no right to unlock, and the system can be restored to the initial state only by pressing the reset button. If the fingerprint is correct, the combined alarm system will not start, the LED light will be on, and the buzzer will not start. After a short delay, the key will send the verification code to the car lock, and the car lock will be unlocked after the verification is correct. When the finger is injured and the fingerprint cannot be used to unlock the lock and the password needs to be used to unlock the lock, if the password is wrong, the combined alarm system will start, the LED light will be off, and the buzzer will start; if the password is correct, the combined alarm system will not start, the LED light will be on, and the buzzer will not activate. Start, its working process is the same as when using fingerprint to unlock.

(3) Bluetooth wireless transmission system: HC-05 Bluetooth module is currently the most widely used Bluetooth module with mature technology and low price. Through the following settings, the signal transmission and encryption between specific two Bluetooth modules can be realized: when using the host computer to initialize the Bluetooth module, first set the master-slave role of the two Bluetooth modules; Bind with the address of the Bluetooth module, so that it only tries to pair with the other party and not with other Bluetooth modules; finally set the connection password and query access code to achieve the encryption of the transmission signal. Using the bluetooth module to wirelessly transmit data and implement data encryption is not only simple, but also has high reliability.

3. Bluetooth fingerprint car lock software design

The system software includes two parts of the program, the key and the car lock. The program flow chart of the key part is shown in Figure 5.

After the key part is started, the initialization operation is performed first and it is judged whether the key is successfully connected with the car lock. If unsuccessful, continue to return to create a connection; if successful, determine whether there is a fingerprint. If there is a fingerprint input, it will perform fingerprint matching. When the fingerprint matching is successful, it will send an unlock signal; if the matching is not successful, it will return to continue to collect fingerprints. When the number of fingerprint input reaches the upper limit, power off and exit.

The program flow chart of the lock part is shown in Figure 6. After the system is started, the initialization operation is performed, and it is judged whether the car lock is connected to the key. If the connection is successful, receive the verification code and match it with the verification code stored in the car lock system. If the matching is successful, the lock will be unlocked; if the matching is unsuccessful, the verification code will continue to be received.

Summarize

At present, with the increase of the number of automobiles in society, the automobile safety problems it brings are also becoming more and more significant. As a human body recognition technology, fingerprint recognition can increase the anti-theft ability of car doors to a certain extent. However, there are few car locks with fingerprint recognition on the market, and they are all fixed on the car itself, and there is no fingerprint that can be used remotely Identify the locking system. For this reason, this paper combines the Bluetooth module with the fingerprint identification module through a single-chip microcomputer, and designs a Bluetooth car lock system based on fingerprint identification. In addition, the system adopts the fingerprint unlocking method, which is more reliable than the traditional unlocking method. At the same time, it can also ensure that the car lock will not be opened by others after the key is lost or stolen, and the safety performance is greatly enhanced. Through many experiments, it can be seen that the Bluetooth car lock system based on fingerprint recognition designed in this paper can remotely unlock the door with fingerprint recognition, and its unlocking accuracy within 5 m is as high as 97%.

The car lock system has the advantages of low cost, high safety factor, convenient use and automatic alarm function, and is a small safety device that can bring more convenience to people using cars at present and in the future.

The above is the bluetooth car lock development example introduced by Shenzhen Zuchuang Microelectronics Co., Ltd. for you. If you have a bluetooth fingerprint car lock solution development needs, you can trust us. We represent a variety of single-chip microcomputers, voice chips, dual-mode Bluetooth ICs, and wifi chips. Brands include Songhan MCU, Yingguang MCU, Jerry Bluetooth, Ankai Bluetooth, Allwinner, and Realtek. Our technical services include: PCB design, microcontroller development, Bluetooth solutions, software and hardware custom development, APP development, small program development, WeChat official account development, etc. It can also undertake the design of intelligent electronic products, the development of living appliances, the research and development of beauty equipment, the application of Internet of things platform, the smart home control system, the development of TWS earphones, Bluetooth earphone speakers, the development of children's educational toys, the design of electronic education products, etc.