Fingerprint click - the complete biometric solution

In the settings window, you can set the different CMOS image sensor settings such as the exposure time or global gain. Once you hit SAVE, these settings will be sent from the PC to the click and stored in the clicks EEPROM.

Fingerprint click settings

Using the click with a host MCU

The click can also communicate with an external host over SPI. We have made a simple example that shows how to do it. Let's look at the example in which we will interface a STM32F107 host MCU with the Fingerprint click.

We start of by initializing SPI communication and the TFT display, after which we will ping the click until we get a FP_READY byte as a response.

     SPI3_Init_Advanced( _SPI_FPCLK_DIV2, _SPI_MASTER | _SPI_8_BIT |
                    _SPI_CLK_IDLE_LOW | _SPI_FIRST_CLK_EDGE_TRANSITION |
                    _SPI_MSB_FIRST | _SPI_SS_DISABLE | _SPI_SSM_ENABLE |
                    _SPI_SSI_1, &_GPIO_MODULE_SPI3_PC10_11_12 );

     GPIO_Digital_Output( &GPIOD_BASE, _GPIO_PINMASK_13 );
     Delay_ms(3000);

     
     TFT_Init_ILI9341_8bit(320, 240);
     TFT_Set_Pen(CL_BLACK, 1);
     TFT_Set_Font(TFT_defaultFont, CL_BLACK, FO_HORIZONTAL);
     TFT_Fill_Screen(CL_Aqua);

     TFT_Write_Text("TFT Initialized, waiting for fingerprint click",10,10);
     Delay_ms(1000);
     TFT_Set_Address_Ptr(0,0);
     delay_ms(10000); // wait for the click to go out of bootloader mode
     
     
     TFT_Write_Text("Fingerprint ready test...", 10, 50);
     fingerprint_is_ready();

Every command sent has it's appropriate response, therefore, all the commands will ping the click until they get the right response. If something goes wrong, the MCU will continue to ping and be stuck forever in this loop. This is the case for all the functions used here. Let's take a look at the fingerprint_is_ready function for a clear example:

void fingerprint_is_ready()
{
     uint8_t temp_spi_buffer;
     CS_PIN = 0;
     delay_ms(10);
     Spi_Write(FP_TEST);
     delay_ms(20);
     CS_PIN = 1;

     temp_spi_buffer = 0;

     while ( temp_spi_buffer != FP_READY )
     {
           CS_PIN = 0;
           delay_ms(10);
           temp_spi_buffer = SPI_Read(FP_DUMMY);
           temp_spi_buffer = SPI_Read(FP_DUMMY);
           CS_PIN = 1;
           delay_ms(1000);
     }
}

You can see here that we first send a FP_TEST command, once the click receives this command, the internal buffer of the click will be set to FP_READY as a response. Once we issue an SPI_Read command, we should receive this response. The same goes for all other functions: we send a command, and then the internal buffer of the click will be set to the appropriate response.

#include 
#include "fingerprint.h"

sbit CS_PIN at GPIOD_ODR.b13;

unsigned int TFT_DataPort at GPIOE_ODR;
sbit TFT_RST at GPIOE_ODR.B8;
sbit TFT_RS at GPIOE_ODR.B12;
sbit TFT_CS at GPIOE_ODR.B15;
sbit TFT_RD at GPIOE_ODR.B10;
sbit TFT_WR at GPIOE_ODR.B11;
sbit TFT_BLED at GPIOE_ODR.B9;


void main()
{
    SPI3_Init_Advanced( _SPI_FPCLK_DIV2, _SPI_MASTER | _SPI_8_BIT |
                    _SPI_CLK_IDLE_LOW | _SPI_FIRST_CLK_EDGE_TRANSITION |
                    _SPI_MSB_FIRST | _SPI_SS_DISABLE | _SPI_SSM_ENABLE |
                    _SPI_SSI_1, &_GPIO_MODULE_SPI3_PC10_11_12 );

     GPIO_Digital_Output( &GPIOD_BASE, _GPIO_PINMASK_13 );
     Delay_ms(3000);

     
     TFT_Init_ILI9341_8bit(320, 240);
     TFT_Set_Pen(CL_BLACK, 1);
     TFT_Set_Font(TFT_defaultFont, CL_BLACK, FO_HORIZONTAL);
     TFT_Fill_Screen(CL_Aqua);

     TFT_Write_Text("TFT Initialized, waiting for fingerprint click",10,10);
     Delay_ms(1000);
     TFT_Set_Address_Ptr(0,0);
     delay_ms(10000); // wait for the click to go out of bootloader mode
     
     
     TFT_Write_Text("Fingerprint ready test...", 10, 50);
     fingerprint_is_ready();
     TFT_Write_Text("passed", 200, 50);

     TFT_Write_Text("Fingerprint capture image...", 10, 70);
     fingerprint_capture_image();
     TFT_Write_Text("passed", 200, 70);
     
     TFT_Write_Text("Displaying image", 10, 90);
     delay_ms(3000);
     fingerprint_display_image();
     fingerprint_end_image_transfer();

}

Let's look at the whole code now. After we are sure that the click is ready, we send a command for the click to capture an image, and then for the click to send us the image bytes. For every SPI_Read we issue, we will get one byte of the image. Each byte is then sent to the TFT display.

void fingerprint_display_image()
{
     uint8_t temp_spi_buffer;
     uint64_t temp_i;
     CS_PIN = 0;
     delay_ms(10);
     Spi_Write(FP_GET_IMAGE);
     delay_ms(20);
     CS_PIN = 1;
     delay_ms(20);
     TFT_CS = 0;
     TFT_Set_Address_Ptr(0,0);


     for (temp_i = 0; temp_i < 240*320; temp_i++)
     {
        CS_PIN = 0;
        temp_spi_buffer = SPI_READ(FP_DUMMY);
        CS_PIN = 1;
        TFT_Write_Data_ptr(temp_spi_buffer);
     }
     TFT_CS = 0;

}

And that's the whole deal. Getting a fingerprint scan has never been easier. Use the images whoever you seem fit and create your unique biometric security system! All the software mentioned here can be found on Libstock or GitHub. Good luck!