How to Use Grow Fingerprint Reader: Examples, Pinouts, and Specs

The Grow Fingerprint Reader (R503) is a biometric device designed to capture and verify fingerprints for authentication purposes. Manufactured by GROW, this compact and reliable module is widely used in security systems, access control, and other applications requiring secure identification. The R503 combines a fingerprint sensor with an onboard processor to handle image processing, feature extraction, and fingerprint matching.

• Door access control systems
• Time and attendance tracking
• Safe and locker security
• IoT-based biometric authentication
• Embedded systems requiring secure user identification

The following table outlines the key technical details of the Grow Fingerprint Reader (R503):

The R503 module has a 6-pin interface for power and communication. The pinout is as follows:

To use the Grow Fingerprint Reader (R503) in a circuit, connect it to a microcontroller (e.g., Arduino UNO) as follows:

1. Connect the VCC pin to the 5V output of the microcontroller.
2. Connect the GND pin to the ground (GND) of the microcontroller.
3. Connect the TX pin of the R503 to the RX pin of the microcontroller.
4. Connect the RX pin of the R503 to the TX pin of the microcontroller.
5. Optionally, connect the TOUCH pin to a GPIO pin to detect when the sensor is touched.

Below is an example of how to interface the R503 with an Arduino UNO to enroll and verify fingerprints:

#include <Adafruit_Fingerprint.h> // Include the Adafruit Fingerprint library
#include <SoftwareSerial.h>       // Use SoftwareSerial for UART communication

// Define the RX and TX pins for the fingerprint sensor
SoftwareSerial mySerial(2, 3); // RX = Pin 2, TX = Pin 3

Adafruit_Fingerprint finger(&mySerial);

void setup() {
  Serial.begin(9600); // Initialize serial communication with the PC
  while (!Serial);    // Wait for the serial monitor to open
  Serial.println("Initializing fingerprint sensor...");

  // Start the fingerprint sensor
  finger.begin(57600);
  if (finger.verifyPassword()) {
    Serial.println("Fingerprint sensor detected!");
  } else {
    Serial.println("Fingerprint sensor not detected. Check connections.");
    while (1); // Halt execution if the sensor is not found
  }
}

void loop() {
  Serial.println("Place your finger on the sensor...");
  int result = finger.getImage(); // Capture the fingerprint image

  if (result == FINGERPRINT_OK) {
    Serial.println("Fingerprint image captured successfully.");
    result = finger.image2Tz(); // Convert the image to a template
    if (result == FINGERPRINT_OK) {
      Serial.println("Fingerprint template created.");
      result = finger.fingerFastSearch(); // Search for a match
      if (result == FINGERPRINT_OK) {
        Serial.print("Fingerprint matched! ID: ");
        Serial.println(finger.fingerID);
      } else {
        Serial.println("No match found.");
      }
    } else {
      Serial.println("Failed to create template.");
    }
  } else {
    Serial.println("Failed to capture fingerprint image.");
  }

  delay(2000); // Wait before the next attempt
}

• Ensure the power supply is stable and within the specified voltage range (3.6V to 6.0V).
• Avoid exposing the sensor to direct sunlight or harsh environmental conditions.
• Use a clean and dry finger for optimal performance.
• The default UART baud rate is 57600 bps, but it can be configured using the appropriate commands.

1. Fingerprint sensor not detected by the microcontroller:

   • Verify the wiring connections, especially the TX and RX pins.
   • Ensure the sensor is powered correctly (check the VCC and GND connections).
   • Confirm that the baud rate in the code matches the sensor's default baud rate.

2. Fingerprint not recognized:

   • Ensure the finger is placed properly on the sensor.
   • Clean the sensor surface to remove dirt or smudges.
   • Check if the fingerprint template was enrolled correctly.

3. Touch detection not working:

   • Verify the connection of the TOUCH pin to the microcontroller.
   • Ensure the microcontroller pin is configured as an input.

Q: Can the R503 store multiple fingerprints?
A: Yes, the R503 can store up to 1000 fingerprint templates in its internal memory.

Q: How do I reset the fingerprint database?
A: Use the appropriate command from the sensor's datasheet to clear all stored templates.

Q: Can I use the R503 with a 3.3V microcontroller?
A: Yes, the R503 supports an operating voltage as low as 3.6V. However, ensure the UART logic levels are compatible.

Q: What is the default password for the R503?
A: The default password is 0x00000000. It can be changed using the appropriate commands.

By following this documentation, you can effectively integrate the Grow Fingerprint Reader (R503) into your projects for secure and reliable biometric authentication.