Arduino Door Lock Using MFRC522 RFID Reader - DIY Door Lock - RFID Door Lock - Servo Motor Door Lock

In this tutorial, we will be building a simple door lock using an Arduino and an MFRC522 RFID reader. The lock will be activated by a specific RFID tag, and will unlock the door when the tag is presented to the reader.

Materials needed:

• Arduino board (e.g. Arduino Uno)
• MFRC522 RFID reader
• RFID tags
• Servo motor
• Jumper wires
• Breadboard
• 9V battery
• Door latch (e.g. a deadbolt)

First, let's connect the MFRC522 RFID reader to the Arduino. Follow the wiring diagram below to connect the reader to the Arduino:

Next, let's connect the servo motor to the Arduino. The servo motor will be used to turn the door latch and unlock the door. Follow the wiring diagram below to connect the servo motor to the Arduino:

Now that the hardware is set up, let's move on to the software. First, you will need to download the MFRC522 library from the Arduino library manager.

Then, copy and paste the following sketch into the Arduino IDE:

#include <SPI.h>
#include <MFRC522.h>
#include <Servo.h>


#define SS_PIN 10
#define RST_PIN 9


MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance
Servo myservo;  // create servo object to control a servo


void setup() {
  Serial.begin(9600); // Initialize serial communications
  SPI.begin(); // Initialize SPI bus
  mfrc522.PCD_Init(); // Initialize MFRC522
  myservo.attach(3);  // attaches the servo on pin 3 to the servo object
  myservo.write(0);  // sets the servo position according to the angle
}


void loop() {
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;
  }


  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return;
  }


  // Print the UID of the card
  Serial.print("UID tag :");
  String content= "";
  byte letter;
  for (byte i = 0; i < mfrc522.uid.size; i++) 
  {
     Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
     Serial.