Fingerprint identification car alarm system module circuit diagram

Crystal oscillator

Quartz Oscillator 3225 20M OSC

Fingerprint recognition is a kind of biometric identification. It uses the uniqueness and lifetime invariance of fingerprint features to authenticate individual identity, which is extremely safe and easy to use. In this paper, the fingerprint recognition technology is applied to the car anti-theft system, and combined with the GSM wireless communication network to realize remote alarm, which effectively protects the safety of the car.
Working principle: After the vehicle owner stops the fire, the anti-theft device enters the locked state. At this time, if the car key is not in the ON position, fingerprint recognition cannot be performed; only when the car key is in the ON position, the fingerprint recognition can be used to unlock the immobilizer and automatically ignite. In the locked state, the oil circuit and circuit of the car are cut off, and the car key cannot be ignited; if the connection between the fingerprint acquisition module and the control box is forcibly cut, or the fingerprint is forcibly ignited by the car key, the car will pass the horn, Flashing lights and wireless communication network alarms. Insert the password key in the locked state to enter the unlocked state, and perform fingerprint registration/delete, mobile number setting and emergency ignition through the keypad according to the LCD and voice prompts.
USB interface circuit USB interface circuit is mainly realized by file management control chip CH376T, CH376T supports USB device mode and USB host mode, and has built-in basic firmware of USB communication protocol, firmware for processing special communication protocol of MassStorage mass storage device, SD card Communication interface firmware, FAT16 and FAT32, and FAT12 file system management firmware support common USB storage devices and SD cards. The CH376T supports two communication interfaces: SPI interface and asynchronous serial port. This design uses SPI interface to communicate with MCU data. The circuit connection is shown in Figure 2. Serial data input SDI, output SDO, and clock SCK are connected to SPI1_MOSI of STM32F103VC, respectively. SPI1_MISO and SPI1_SCK, the interrupt request output terminal INT is connected to PC0, and the chip select terminal SCS is controlled by PA1. The RESET in the figure is the system reset signal, and the crystal oscillator Y1 selects 12 MHz. When the car mainly performs fingerprint registration/deletion or emergency ignition, the password key (U disk) is connected to J1 to read the password information.

The schematic diagram of the voice circuit voice circuit is shown in Figure 3. It consists of the ISD company's voice chip ISD4004-16 and National Semiconductor's audio power amplifier LM386. ISD4004 -16 recording and playback time is 16 min (segmentable), it uses CMOS technology, single power supply 3 V operation, including oscillator, anti-aliasing filter, smoothing filter, audio amplifier, automatic squelch and high density Level flash storage display. It has a built-in microcontroller SPI bus serial communication interface. Analog voice data can be written directly to a single location without the need for A/D or D/A conversion. The ISD voice circuit has many advantages such as natural sound quality, convenient use, single-chip storage, repeated recording and playback, low power consumption, and power failure. The LM386 operates over a wide voltage range with adjustable voltage gain. It has low power consumption, adjustable voltage supply, large power supply voltage range, few external components and low total harmonic distortion. In this design, the STM32F103VC transmits voice information to the ISD4004 via SPI2. In Figure 3, V1 and V2 are connected to the +3.3 V and +12 V power supplies via a triode. The triode is switched on and off by the PCI1 and PCI2 of the STM32F103VC. The triode is turned on to power the ISD4004 and LM386 only when a voice prompt is required. .