Unable to integrate Fingerprint sensor in Raspberry Pi2

Question

I am trying to connect a R305 v1.6 fingerprint scanner with my Raspberry Pi2 Model B.

Sensor: http://www.sunrom.com/p/finger-print-sensor-r305

I am using pyfingerprint module which supports ZFM-20 fingerprint scanner.

Library: https://github.com/bastianraschke/pyfingerprint

Now after successful installion when I run the example, it says

The fingerprint sensor could not be initialized!

Exception message: The fingerprint sensor port "/dev/ttyUSB0" was not found!

I tried seeing the tty ports using the command dmesg | grep tty, and this the output I get when the sensor is connected:

[    0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2709.boardrev=0xa21041 bcm2709.serial=0x2377eadd smsc95xx.macaddr=B8:27:EB:77:EA:DD bcm2708_fb.fbswap=1 bcm2709.uart_clock=3000000 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000  dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[    0.001458] console [tty1] enabled
[    0.097506] 3f201000.uart: ttyAMA0 at MMIO 0x3f201000 (irq = 83, base_baud = 0) is a PL011 rev2
[    2.061340] systemd[1]: Starting system-getty.slice.
[    2.065794] systemd[1]: Created slice system-getty.slice.

I am unable to decipher where the error is. Is it that the library is not supported with this fingerprint module, or is there some other error.

PS - I also have disabled login shell over serial, as I saw in this tutorial: http://www.instructables.com/id/Read-and-write-from-serial-port-with-Raspberry-Pi/

Update 1: I am connecting the fingerprint scanner using the gpio pins, Ground, 5V, TDX and RX, since it communicates via TTL serial. As I connect the Ground and 5V pins to the scanner, the scanner lights blink. That's the only activity seen on the scanner. I have also tried another scanner, and this too gives the same problem while integration.

Answer 1

Thanks to Joan for solving the problem.

First and foremost, you need a library to run your fingerprint sensor.I found one here: https://github.com/bastianraschke/pyfingerprint

Follow the instructions to install the library in your pi. Then connect your fingerprint scanner to the raspberry using the GPIO ports. You can find what ports corresponds to what in the fingerprint sensor manual. In my case, I was using a Sunrom R305 fingerprint scanner.

The manual for this can be found here: http://www.sunrom.com/p/finger-print-sensor-r305

Next is to disable login shell over serial. Find all the steps here for the same here: http://www.instructables.com/id/Read-and-write-from-serial-port-with-Raspberry-Pi/

You are almost done. The above link will solve almost all the problems. Next up is check the serial port available with your pi. Put this command on the terminal of your pi: dmesg | grep tty.

You'd get a message like this:

[    0.000000] Kernel command line: dma.dmachans=0x7f35 bcm2708_fb.fbwidth=656 bcm2708_fb.fbheight=416 bcm2709.boardrev=0xa21041 bcm2709.serial=0x2377eadd smsc95xx.macaddr=B8:27:EB:77:EA:DD bcm2708_fb.fbswap=1 bcm2709.uart_clock=3000000 bcm2709.disk_led_gpio=47 bcm2709.disk_led_active_low=0 vc_mem.mem_base=0x3dc00000 vc_mem.mem_size=0x3f000000  dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
[    0.001458] console [tty1] enabled
[    0.097506] 3f201000.uart: ttyAMA0 at MMIO 0x3f201000 (irq = 83, base_baud = 0) is a PL011 rev2
[    2.061340] systemd[1]: Starting system-getty.slice.
[    2.065794] systemd[1]: Created slice system-getty.slice.

Here it shows that my port is ttyAMA0. Yours may be something else. Go to this folder in your library: /usr/share/doc/python-fingerprint/examples/.

It contains all the files for running the fingerprint scanner. Open one file, for instance example_search.py. There is a try block in every file, something like this:

try:
    f = PyFingerprint('/dev/ttyUSB0', 57600, 0xFFFFFFFF, 0x00000000)

    if ( f.verifyPassword() == False ):
        raise ValueError('The given fingerprint sensor password is 
wrong!')

This code is basically trying to connect to your fingerprint scanner. It assumes that the port you are using is /dev/ttyUSB0. In my case, the port was /dev/ttyAMA0. So you just need to replace /dev/ttyUSB0 in all the python codes to /dev/tty****, where **** is your port(AMA0 in my case). Then save the file and run it, and it should work.

Answer 2

I used it with a Serial to USB converter (CP2102) The python script will detect the /dev/ttyUSBx port as valid.