Introduction Anti-theft remote controls are mainly used in access control devices such as cars, garage doors, security doors, interior doors, and safes. They can control the opening and closing of access control devices. In anti-theft mode, an anti-theft alarm signal is emitted when the access control is illegally opened, bumped, moved, or vibrated. Currently, fingerprint recognition anti-theft remote controls on the market use first-generation optical fingerprint recognition technology, which can only scan the surface of the finger skin (also known as the "dead skin layer") and cannot penetrate into the dermis. Therefore, the cleanliness of the finger surface directly affects the recognition effect. Furthermore, if a person creates a fingerprint mold based on their own fingerprint, it may also pass through the recognition system. Although this fingerprint recognition technology can identify the user, it is neither secure nor stable. Scratch-type live fingerprint readers emit electronic signals through a capacitive sensor. These signals penetrate the surface of the finger and reach the live skin layer (also known as the "dermis"), directly reading the fingerprint pattern, thus greatly improving system security. Using scratch-type live fingerprint recognition technology, the anti-theft remote control collects the user's live fingerprint and sends it to the remote control receiver for comparison with the legitimate fingerprint stored in the receiver. Only when the fingerprints match can the user perform other operations on the remote control; otherwise, an anti-theft alarm signal is issued. Employing live fingerprint recognition technology to verify the user's identity improves the system's anti-theft level, security, and stability. 1. Design of the Anti-theft Remote Control Transmitter The swipe-type live fingerprint recognition anti-theft remote control consists of two parts: an anti-theft remote control transmitter and an anti-theft remote control receiver. The transmitter is carried by the user, while the receiver is placed inside the access control device to be protected. The transmitter uses an MSP430F12X processor as its core, configuring the working status of the swipe-type live fingerprint sensor MBF310, the wireless transmitter/receiver chip nRF401, and the parameter configuration chip AT93C46, including fingerprint data reading, wireless transmission of fingerprint data and encrypted data, and wireless transmission of control commands. The AT93C46 stores 256 bits of parameter configuration data for encrypting the transmitted data; the nRF401 operates in wireless transmission mode. The MBF310 operates in SPI mode and connects to the SPI bus of the MSP430F12X processor. The MSP430F12X initializes the MBF310 sensor's operating state via the SPI bus, configuring it to SPI mode with FIFO interrupt enabled. When a finger slides across the MBF310, it collects fingerprint data and stores it in a FIFO buffer. When the FIFO buffer is full, an interrupt signal is generated. Upon receiving the FIFO buffer full interrupt signal, the MSP430F12X processor immediately reads the fingerprint data collected by the MBF310 via the SPI bus. It then performs an OR operation between the read fingerprint data and the configuration word within the AT93C46 to encrypt the data, and transmits the encrypted data through the nRF401. This achieves functions such as fingerprint acquisition, fingerprint data reading, encryption, wireless transmission, and wireless transmission of control commands. The circuit connection diagram of the anti-theft remote control transmitter is shown in Figure 1. [align=center]Figure 1 Circuit connection diagram of the anti-theft remote control transmitter[/align] 2. Design of the anti-theft remote control receiver The anti-theft remote control receiver consists of an MSP430F12X processor, a wireless transmitter/receiver chip nRF401, a parameter configuration chip AT93C46, a fingerprint template memory FM24C64, buttons, and indicator lights. When the anti-theft remote control receiver is working normally, the MSP430F12X processor selects nRF401 as the wireless receiving mode to receive data and commands transmitted by the anti-theft remote control transmitter in a timely manner. When fingerprint data is received, the MSP430F12X processor uses the 256-bit configuration word in the AT93C46 to decode the received encrypted fingerprint, obtaining the real live fingerprint data collected by the MBF310 in the anti-theft remote control transmitter. Then, the decoded fingerprint data is compared with the fingerprint template data pre-stored in the fingerprint template memory FM24C64. If the comparison result is true, it indicates that legitimate identity verification has been obtained, and the anti-theft remote control receiver can receive the control commands of the anti-theft remote control transmitter (commands set on the buttons on the anti-theft remote control transmitter). Otherwise, it will not respond to the command data transmitted by the anti-theft remote control transmitter. The buttons on the anti-theft remote control receiver are used to establish the fingerprint template, and the indicator light indicates the current working status of the anti-theft remote control receiver. Output ports 1 to 6 are output control signals generated according to the remote control commands. The circuit connection diagram of the anti-theft remote control receiver is shown in Figure 2. [align=center] Figure 2 Circuit connection diagram of the anti-theft remote control receiver[/align] 3. Application Example Taking this design as a car anti-theft remote control as an example, the car anti-theft remote control consists of two parts: a car anti-theft remote control transmitter and a car anti-theft remote control receiver. The car anti-theft remote control transmitter is carried by the car owner, and the car anti-theft remote control receiver is installed in the car. The three command operation buttons of the car anti-theft remote control transmitter are defined as starting the car system (KEY1), stopping the car system (KEY2), and finding the car (KEY3). The output control ports 1-6 of the car anti-theft remote receiver are defined as follows: alarm sounding, headlight flashing, door lock/unlock, trunk opening, main circuit on/off, and ignition/off control signals, respectively. All operations of the car anti-theft remote require fingerprint recognition. First, the operator's finger (the finger whose fingerprint template has been created in the car anti-theft remote receiver) lightly slides across the fingerprint recognition window. After the car anti-theft remote transmitter collects the fingerprint, it encrypts the fingerprint data using an encoding encryption algorithm and transmits it via FSK. The car anti-theft remote receiver within the effective range receives the encrypted data, decrypts it using a decoding algorithm, and then compares it with the stored fingerprint template data. If the comparison result is true, the operator's identity is successfully confirmed, and the receiver can receive commands from the remote transmitter; otherwise, the receiver does not receive commands from the remote transmitter. If a car is forcibly operated without the operator's legal identity, the anti-theft remote receiver will send alarm control signals (such as sounding the alarm and flashing headlights) and execute other anti-theft control signals (such as disconnecting the main circuit, turning off the car, and locking the doors). Conclusion The anti-theft remote transmitter designed in this paper uses the MBF310 swipe-type live fingerprint recognition chip, which belongs to the second-generation fingerprint recognition technology. This effectively overcomes the shortcomings and deficiencies of the first-generation fingerprint recognition technology, such as low recognition rate and the inability to recognize rubber-molded fingerprints, thus improving the security level and correct recognition rate. The nRF401 wireless transceiver chip uses FSK technology, and the remote control distance can reach 800 m. In both the anti-theft remote transmitter and receiver, the AT93C46 is the codec configuration chip, storing 256 bits of codec data. The remote transmitter uses a 256-bit encoding encryption algorithm when transmitting data, which can prevent the remote transmission data from being intercepted and cracked, and the remote transmitter from being counterfeited. Remote control operation can only be performed when the codec data of the remote transmitter and receiver are the same, thus improving the security level. The fingerprint template memory in the anti-theft remote receiver uses an 8 KB high-speed ferroelectric memory FM24C64, which can be read and written 1010 times without failure and retain data for 10 years without loss in the event of power failure. The remote transmitter and receiver use the ultra-low power 16-bit processor MSP430F12X as the core for data processing and control, which improves the data processing speed and the intelligence of the system and reduces power consumption. References [1] Hu Dake. MSP430 series FLASH type ultra-low power 16-bit microcontroller [M]. Beijing: Beijing University of Aeronautics and Astronautics Press, 2001. [2] Hu Dake. MSP430 series microcontroller C language programming and development [M]. Beijing: Beijing University of Aeronautics and Astronautics Press, 2003. [3] Wei Xiaolong. MSP430 series microcontroller interface technology and system examples [M]. Beijing: Beijing University of Aeronautics and Astronautics Press, 2002.