How to use Fingerprint sensor with Arduino？

Integrating the fingerprint recognition function into an Arduino project can add a layer of security protection to your electronic devices. In this article, we will introduce how to use a fingerprint sensor with Arduino, including connection, library installation, and the processes of fingerprint registration and recognition.

Required Materials

• Arduino development board: Such as Arduino UNO.

• Fingerprint sensor module: Such as an optical fingerprint sensor.

• Jumper wires: Used to connect the Arduino and the fingerprint sensor.

• LED (optional): Used to indicate the fingerprint matching result.

• Soldering iron (optional): Used to solder pins to the fingerprint sensor.

Steps

Connect the fingerprint sensor to the Arduino

First, connect the fingerprint sensor to the Arduino. The following are common connection methods:

Power connection:

• Connect the red wire to the 5V pin of the Arduino.

• Connect the black wire to the GND pin.

Data transmission connection:

• Connect the green data wire to digital pin 2 (RX) of the Arduino.

• Connect the white data wire to digital pin 3 (TX) of the Arduino.

Make sure the connections are correct so that data can be transmitted normally between the Arduino and the fingerprint sensor.

Install the Adafruit Fingerprint Sensor Library

To interact conveniently with the fingerprint sensor, it is recommended to use the fingerprint sensor library provided by Adafruit. Follow these steps to install it:

1. Open the Arduino IDE.

2. Navigate to Tools > Manage Libraries.

3. In the Library Manager, search for "Adafruit Fingerprint Sensor Library".

4. Click the "Install" button to install it.

Register a new fingerprint

Before using the fingerprint sensor, you need to register the fingerprint data into the sensor's storage. Follow these steps to register:

1. In the Arduino IDE, navigate to File > Examples > Adafruit Fingerprint Sensor Library > Enroll.

2. Upload the example code to the Arduino.

3. Open the Serial Monitor and set the baud rate to 9600.

4. Follow the prompts in the Serial Monitor, enter the fingerprint ID and place the specified finger on the sensor for registration.

Repeat the above process to register multiple fingerprints.

Recognize fingerprints

After completing fingerprint registration, you can use the following example code to recognize the registered fingerprints:

1. In the Arduino IDE, navigate to File > Examples > Adafruit Fingerprint Sensor Library > Fingerprint.

2. Upload the example code to the Arduino.

3. Open the Serial Monitor and set the baud rate to 9600.

4. Place the registered finger on the sensor and check the recognition result.

If necessary, you can add peripherals such as LED indicator lights or electromagnetic locks to the code to provide feedback when recognition succeeds or fails.

Precautions

• Power requirements: Some fingerprint sensors require a 3.3V power supply. Connect according to the specification sheet of the sensor.

• Pin compatibility: Not all Arduino boards support software serial communication on all pins. Refer to the documentation of your Arduino model.

• Debugging: If you encounter problems during the recognition process, check whether the connections are correct, ensure that the fingerprint has been registered correctly, and confirm that the appropriate library version is used.

By following the above steps, you can successfully use the fingerprint sensor with Arduino and add biometric functionality to your project.