Comments: Fingerprint Scanner (GT-521Fxx) Hookup Guide


Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Member #1396902 / about 6 years ago / 3

    Interfacing Library for .NET

    We recently released an interfacing library in .NET for the Fingerprint Scanner (GT-521Fxx). The library is completely open source under MIT license.

    Library Features

    • All documented commands are implemented (2018-06-25)
    • Operations are all asynchronous
    • No dependencies
    • MIT License
  • Member #57306 / about 6 years ago / 2

    Loved the earlier GT-511C1R... apart from the fact that it just didn't work at all well for me right at the "source"... it didn't scan my fingerprints very well. Everything else was first class, and very sophisticated. (With that come the fact that hooking into the interface is not trivial, but it IS (very) "do-able".

    As this device seems to use the same, or nearly the same SDK_Demo (Windows) software, I am hoping that it has all of the strengths of the old device.

    Have people found, once they have mastered the SDK_Demo software, and the fairly trivial hookup issues, that this reads prints well? Anyone with experience of this and the older device have any comments to share?

    • The new version of the fingerprint should function the same as long as you connect to the pins sufficiently. I did have some issues scanning fingerprints a few times but it was similar with any other fingerprint scanner that I've tested (i.e. pressing too hard, not placing the finger sufficiently on the scanner, etc.). It should be linked in the troubleshooting section => [ ].

      There are some minor updates in the SDK-Demo software, scanner's features, and PCB. You should not notice a difference in the overall functionality. From my experience, it seems to work well. =)

  • Member #1581051 / about 3 years ago / 1

    Anyone else having trouble UPLOADING a database of fingerprints to the GT-521F32? I have multiple units at different locations that will all share the same set of taught fingerprints. Using the "Fingerprint Embedded System Demo AP", using the GET DATABASE function works fine. I save the file then go to upload to another GT-521F32. The program only shows "Adding of 0th template..." in the RESULTS textbox, then alarms with "Communication Error". All other functions are still operable, however. Thanks!

  • Member #1613831 / about 4 years ago / 1

    The SDK_Demo software doesn't seem to be working for my FTDI board. I set the COM port correctly and set the baud rate to 9600, but when I click Open, nothing happens. There is a red light light that flashes once on my FTDI board but nothing shows up in the result window. Any idea on what the issue could be?

    • Hmm, that's odd. My quick suggestion would be to ensure that your connecting to the correct side of the fingerprint scanner, and the wire is Tx to Rx and vice versa. I am not sure if you used the Qwiic cable to breadboard? If the USB cable is not new, I suggest trying a different cable to ensure that it did not go bad.

      Let me know if that works. I may need to find out more about your setup if you still have problems.

  • Member #1471723 / about 5 years ago / 1

    Hi everyone, I built a fingerprint reader device using an ESP8266 for access control and I installed it on two different places. It works very well almost all the time, however, after 2-3 months working it starts giving me communication errors through the Serial and stops working, so I go and change the fingerprint reader (GT-521F52) for a new one and start working good again. Very strange.

    It happened 3 times on both devices, one device is in the entrance of a coworking space inside with air conditioning all day long so the temperature/humidity is stable. The other device is in the exterior entrance of a gym with a high humidity/temperature environment.

    I was checking the datasheet of the reader looking for the operating temperature but it says that in version 1.1 of the datasheet it was removed also the Reliability data was removed too. Does this mean that this device is not reliable for production devices? Any idea?

    • santaimpersonator / about 5 years ago / 2

      Hey there, that sounds like a question best directed at the sensor manufacturer. Their website and email address are listed on the cover page of the datasheet.

  • Member #1546151 / about 5 years ago / 1

    Has anyone been able to get the ICPCK touch IC to work? I have the cables necessary but there is no documentation on how to actually implement it into the code. It' be great if someone that actually got it to work could send over their code or some sample code to help me out.

    • There should be a function that checks to see if there is a finger in the library: fps.IsPressFinger().

      However, if you decide to try to use the ICPCK working, I think a simple if() statement to check if that pin is high or low (like a button press) should be sufficient enough. This is assuming you are using a logic level converter between your 5V Arduino and the fingerprint scanner's ICPCK pin. I have not tested this out but it should looks something like this similar to a button press:

      //add this before the setup()
      const int button1Pin = 2;  // pushbutton 1 pin
      int button1State; // variables to hold the pushbutton states
      const int ledPin =  13;    // LED pin on Arduino to check if this is working
      void setup(){  //remember, you only need one setup(), so don't copy this line ;P  ...
        // Set up the pushbutton pins to be an input
        //(we'll use the internal pullup resistors so we do not have to use more components):
        pinMode(button1Pin, INPUT_PULLUP);    
        // Set up the LED pin to be an output:
        pinMode(ledPin, OUTPUT);  
      }//end of setup() function
      void loop(){//remember, you only need one loop(), so don't copy this line either ;P  ...
        button1State = digitalRead(button1Pin);//check button press
        if (button1State == LOW){
          digitalWrite(ledPin, HIGH);  // turn the LED on
          digitalWrite(ledPin, LOW);  // turn the LED off
        //... other fingerprint scanner functions?
      }//end loop

      I hope this helps. =)

  • Member #1504914 / about 5 years ago / 1

    can I use the sensor with hardware serial on ESP32?

    • Doing a quick test by selecting the ESP32 Dev Module in the Arduino IDE, the ESP32 fails to compile with the fingerprint scanner library. Doing a quick search online, I did not find anyone that had ported the library specifically for the ESP32.

      I suggest trying the method I explained earlier with the dedicated ATmega328P.

    • The fingerprint scanner uses a serial UART. However, the library was written with the software serial library on an ATmega328P. If you follow the packet structure listed in the programming guide from the manufacturer, you could theoretically get it working with the hardware serial on the ESP32. I have not seen it working with the ESP32 since it is a different microcontroller. It may not compile correctly when using a different microcontroller.

      While redundant, it would be easier to have a dedicated ATmega328P communicate with the fingerprint scanner module. Then send a flag or serial packet to the ESP32 to indicate a fingerprint match or fail.

  • Member #584512 / about 5 years ago / 1

    Potential n00b question here, but if I pick up the RedBoard Qwiic version, could I just connect this with a single Qwiic-to-Qwiic cable and be done with it?

    • I just got to a computer to compare. Unfortunately, the pinout for the fingerprint scanner do not match the Qwiic pinout so you would not be able to connect the Qwiic-to-Qwiic cable with the RedBoard Qwiic. It just happens that the connectors are the same and you can use the Qwiic-to-breadboard adapter to connect between the scanner and the RedBoard's female headers.

    • Good question. The Qwiic connector is supposed to be for I2C. The fingerprint scanners communicate via a UART port and they happen to have the same type of connector. Hmmm, it might be possible if you adjust the software serial pin definitions for A4 and A5 but you would also need to ensure that the physical pins match the connection. I have not tried that before.

      Try looking at the Qwiic connections and verify it against the fingerprint scanner's pins shown in the hardware overview. I might be able to answer this better if I were at a computer during a normal business day instead my smartphone. ;)

  • Problem in enrolling the finger print in GT-521F32. I am using arduino uno and GT-521f32 with sparkfyn finger print TTL library. The issue is when we are enrolling a finger it will take three finger templates to enroll finger . We want to keep the three finger in same position if we need to enroll a finger,if we put some difference from first finger then the enrollment will be failed and want to restart the enrolling process.Can any one please help me with above issue.

    • Sorry, I just noticed this comment. When enrolling, you need to have three successful enrollments before the sensor is able to save the fingerprint. Make sure that you place your finger in the same position when enrolling for the scanner to properly enroll.

      Try checking the troubleshooting section for more information if you have not already. It may be easier to enroll and verify using the SDK demo software.

  • Member #908549 / about 5 years ago * / 1

    I'm currently using the Arduino and resistor voltage division because I don't want to buy anything but I'd eventually like to use this with a Raspberry Pi. If I bought the FTDI breakout, would I be able to somehow integrate the fingerprint sensor into a Python program?

  • Member #908549 / about 6 years ago / 1

    Is it possible to change the TX and RX pins on the Arduino? My Arduino has seen better days and its pin 4 is broken.

    • Yes, it is possible. There should be a note in the section called Software Serial w/ Other Microcontrollers. Not all the pins can support change interrupts for a serial Rx pin depending on what Arduino microcontroller is used. However, there are a few other options. It links to the Software Serial Library.

If you've found an issue with this tutorial content, please send us your feedback!