Fingerprint click

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Fingerprint click
Fingerprint-click-front.jpg
Fingerprint click
IC/Module GTS-511E2 datasheet
Interface Windows application and SPI
Power supply 3.3V
Product page Fingerprint click
Schematic Fingerprint click schematic

Fingerprint click is the simplest way to integrate biometric security to your design. The smallest optical touch fingerprint sensor in the world is featured on the click — GTS-511E2. The sensor takes a digital image of the fingerprint pattern using visible light. The board is designed to use a 3.3V power supply.

The board can work as a standalone USB HID, using the Fingerprint PC application, or as an SPI slave communicating with a host MCU. USB HID is a USB human interface device.

Features and usage notes

CMOS image sensor

A CMOS image sensor is the main component in most digital cameras today. Compared to a CCD sensor it has low power consumption and low dissipation.

To distinguish between 2D images and a real fingerprint the CMOS image sensor has a special lens and covering. Considering how dark it is when you press your finger to the lens, an LED illuminates it from one side, while the other side does the job of sending the image through the lens to the processor.

Windows application

Fingerprint click carries an STM32 MCU for processing the images and forwarding them to an external MCU or PC. We created a Windows application that provides an interface so you can easily use the Fingerprint click. The following steps describe how the application works:

  • 1.Place your finger on the sensor on the click.
  • 2.Press the button in the bottom, left corner of the screen.
  • 3.After you see the image of your fingerprint, press the button at the bottom, right corner of the screen to save the image. If you want to add more fingerprint images just repeat the process.

Pinout diagram

This table shows how the pinout on Fingerprint click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes Pin Mikrobus logo.png

mikroBUStm

Pin Notes
MCU ready pin READY# 1 AN X PWM 16 NC
NC 2 RST INT 15 NC
SPI chip select pin CS# 3 CS TX 14 MCU_RX UART transfer pin
SPI clock pin MCU_SKC 4 SCK RX 13 MCU_TX UART receive pin
SPI master in slave out pin for the MCU MCU_MISO 5 MISO SCL 12 NC
SPI master out slave in pin for the MCU MCU_MOSI 6 MOSI SDA 11 NC
3.3V Power supply 3.3V 7 +3.3V +5V 10 NC
Ground GND 8 GND GND 9 GND Ground

Programming

This code initializes SPI communication and the TFT display. After waiting for the Fingerprint click to go out of bootloader mode, the MCU sends a series of SPI commands for the Fingerprint to capture and send the fingerprint image. Every image byte received from the click is being sent onto the TFT display

 1 void main()
 2 {
 3     SPI3_Init_Advanced( _SPI_FPCLK_DIV2, _SPI_MASTER | _SPI_8_BIT |
 4                     _SPI_CLK_IDLE_LOW | _SPI_FIRST_CLK_EDGE_TRANSITION |
 5                     _SPI_MSB_FIRST | _SPI_SS_DISABLE | _SPI_SSM_ENABLE |
 6                     _SPI_SSI_1, &_GPIO_MODULE_SPI3_PC10_11_12 );
 7 
 8      GPIO_Digital_Output( &GPIOD_BASE, _GPIO_PINMASK_13 );
 9      Delay_ms(3000);
10 
11      
12      TFT_Init_ILI9341_8bit(320, 240);
13      TFT_Set_Pen(CL_BLACK, 1);
14      TFT_Set_Font(TFT_defaultFont, CL_BLACK, FO_HORIZONTAL);
15      TFT_Fill_Screen(CL_Aqua);
16 
17      TFT_Write_Text("TFT Initialized, waiting for fingerprint click",10,10);
18      Delay_ms(1000);
19      TFT_Set_Address_Ptr(0,0);
20      delay_ms(10000); // wait for the click to go out of bootloader mode
21      
22      
23      TFT_Write_Text("Fingerprint ready test...", 10, 50);
24      fingerprint_is_ready();
25      TFT_Write_Text("passed", 200, 50);
26 
27      TFT_Write_Text("Fingerprint capture image...", 10, 70);
28      fingerprint_capture_image();
29      TFT_Write_Text("passed", 200, 70);
30      
31      TFT_Write_Text("Displaying image", 10, 90);
32      delay_ms(3000);
33      fingerprint_display_image();
34      fingerprint_end_image_transfer();
35 
36 }

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