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

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 => [ https://learn.sparkfun.com/tutorials/fingerprint-scanner-gt-521fxx-hookup-guide/troubleshooting ].

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. =)

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.

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.

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
  }
  else{
    digitalWrite(ledPin, LOW);  // turn the LED off
  }

  //... other fingerprint scanner functions?
  //.
  //.
}//end loop

I hope this helps. =)

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.

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. ;)

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.

Good question. =) I have not tested this yet but there is a GitHub repo using Python on a Pi that might be of some use => https://www.raspberrypi.org/forums/viewtopic.php?p=636148&sid=2b7840e6f1fbf30e4b5403e10477b302#p636148. It was linked in the Resources and Going Further. You might need to adjust the code as explained in this guide to check the number of IDs available for your scanner.

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 Arduino.cc Software Serial Library.