RFID Lock System With Servo Using Arduino

Hey guys, welcome back to Techatronic. In this article, we are going to discuss a very interesting project with Arduino. Have you ever seen a smart lock in which you have to put the card on the reader to get access? Well, we will make our own smart lock, an RFID lock system that needs a unique card to perform a specific action. We are using an RC522 RFID reader/writer module and an Arduino UNO board for making this smart lock. You can view the card status on a 16×2 LCD that we used here. Do check out more interesting projects on Arduino and Raspberry Pi made by us.

rfid lock system

Working of the Project

The RFID lock system works as when you will put the correct card to open the servo lock then “card is valid” this message will display and the green LED will turn on. The door will close automatically after a delay of three seconds, you can adjust this time in the code. For the invalid card the red LED will turn on with the message “card is invalid” and the buzzer starts beeping. The servo motor will rotate to open or close the gate. When you put an RFID card on the reader module then open the serial monitor to view the tag id of that card as shown below.

serial monitor value

Add the tag id of the card that you want to use to open the lock in this section of the code.

rfid code

Components Required

  • Arduino UNO
  • 16×2 LCD and I2C module
  • Servo motor and buzzer
  • Green and red LED
  • Jumper wires and a breadboard
  • RC522 RFID module
  • 220-ohm resistors and a 10K potentiometer
  • USB cable for uploading the code
  • Power supply
rfid lock system component

Arduino RFID Lock Circuit Diagram

With I2C module

If you are using the I2C module then find the address of the module first.

rfid lock system circuit
Arduino UNORFID – RC522 Module
10   PinSDA    Pin
13   PinSCK     Pin
11   PinMOSI  Pin
12   PinMISO  Pin
No  PinIRQ     Pin
GNDGND
9     PinRST      Pin
3.3 V3.3 V
Arduino UNOServo Motor
D3 PinOUT Pin  ( Orange Colour )
( +5V ) VCC         ( Red Colour )
GND  GND        ( Black Colour )
Arduino UNOI2C LCD Module
( +5V )( +5V ) 
GND GND 
A4 Pin SDA Pin
A5 Pin SCL Pin
16 * 2 LCDI2C LCD Module
16 Pin Connect16 Pin Connect
Arduino UNOBuzzer
D6 PinPositive
GNDNegative
Arduino LED RLED G220 Ohm Resistor
D7 PinAnode Pin  
D5 Pin Anode Pin 
GND  Terminal 1
 Cathode PinCathode PinTerminal 2

You can take a reference from one of our articles on I2C with LCD.

Arduino GND pin -> RFID GND pin, I2C GND pin, Servo negative wire, buzzer negative leg, LEDs negative leg via 220-ohm resistor

Arduino 5 volts -> I2C VCC pin, Servo positive wire

RFID 3.3 volts -> Arduino 3.3 volts

RFID RST pin -> digital-9 pin

RFID MISO pin -> digital-12 pin

RFID MOSI pin -> digital-11 pin

RFID SCK pin -> digital-13 pin

RFID SDA pin -> digital-10 pin

Green LED positive leg -> digital-5 pin

Red LED positive leg -> digital-7 pin

Buzzer positive leg -> digital-6 pin

rfid module

Without I2C module

rfid lock system circuit
Arduino UNORFID – RC522 Module
10   PinSDA    Pin
13   PinSCK     Pin
11   PinMOSI  Pin
12   PinMISO  Pin
No  PinIRQ     Pin
GNDGND
9     PinRST      Pin
3.3 V3.3 V
Arduino UNOServo Motor
D3 PinOUT Pin  ( Orange Colour )
( +5V )VCC         ( Red Colour )
GNDGND        ( Black Colour )
Arduino UNOBuzzer
D6 PinPositive
GNDNegative
Arduino UNO16*2 LCD10K Potentiometer
GND VSS, K 
+5 VVDD, A 
GNDVSS (Ground)Terminal 1
 VEE ( Contrast )Terminal 2
+5 VVDD ( +5V )Terminal 3
A0 PinRS ( Register Select ) 
GNDRW ( Read\Write ) 
A1 PinE ( Enable ) 
A2 PinD4 
A3 PinD5 
A4 PinD6 
A5 PinD7 
Arduino LED RLED G220 Ohm Resistor
D7 PinAnode Pin  
D5 Pin Anode Pin 
GND  Terminal 1
 Cathode PinCathode PinTerminal 2

All the connections are the same except the I2C module. Connect the LCD pins with the analog pins of the Arduino as shown in the diagram. You can take help from our article on the working of LCD with Arduino.

rfid lock system

Arduino Rfid Lock Code

NOTE: Please upload the given code according to the circuit you have made. Install <SPI.h>, <MFRC522.h>, <LiquidCrystal_I2C.h>, <Wire.h> libraries to the IDE first and then compile the code. Check here to know how to install a zip library to the Arduino IDE.

With I2C module

 // TECHATRONIC.COM  
 // SPI Library  
 // https://github.com/PaulStoffregen/SPI  
 // MFRC522 Library  
 // https://github.com/miguelbalboa/rfid  
 #include <SPI.h>  
 #include <MFRC522.h>  
 #include <Servo.h>  
 #include <Wire.h>   
 #include <LiquidCrystal_I2C.h>  
 LiquidCrystal_I2C lcd(0x3F,16,2);  
 Servo s1;  
 #define SS_PIN 10  
 #define RST_PIN 9  
 #define LED_G 5  //define green LED pin  
 #define LED_R 7  //define red LED  
 #define BUZZER 6 //buzzer pin  
 MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance.  
 //Servo myServo; //define servo name  
 void setup()   
 {  
  Serial.begin(9600);  // Initiate a serial communication  
  SPI.begin();     // Initiate SPI bus  
   lcd.init();             
  lcd.backlight();  
 ;  
  mfrc522.PCD_Init();  // Initiate MFRC522  
  s1.attach(3); //servo pin  
  // myServo.write(0); //servo start position  
  pinMode(LED_G, OUTPUT);  
  pinMode(LED_R, OUTPUT);  
  pinMode(BUZZER, OUTPUT);  
  noTone(BUZZER);  
  Serial.println("Put your card to the reader...");  
  Serial.println();  
  lcd.setCursor(0,0);  
  lcd.print(" Put your card   ");  
 }  
 void loop()   
 {  
  // Look for new cards  
  if ( ! mfrc522.PICC_IsNewCardPresent())   
  {  
   return;  
  }  
  // Select one of the cards  
  if ( ! mfrc522.PICC_ReadCardSerial())   
  {  
   return;  
  }  
  //Show UID on serial monitor  
  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.print(mfrc522.uid.uidByte[i], HEX);  
    content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));  
    content.concat(String(mfrc522.uid.uidByte[i], HEX));  
  }  
  Serial.println();  
  Serial.print("Message : ");  
  content.toUpperCase();  
  if (content.substring(1) == "5B 2F 4B 0C") //change here the UID of the card/cards that you want to give access  
  {  
   Serial.println("Authorized access");  
   Serial.println();  
     lcd.setCursor(0,0);  
     lcd.print(" CARD IS VALID      ");  
     lcd.setCursor(0,1);  
     lcd.print("Opening the Door   ");  
     digitalWrite(LED_G, HIGH); //Green LED ON  
     s1.write(0);  
     delay(3000);  
     s1.write(90);  
     lcd.setCursor(0,1);  
     lcd.print("closing the Door   ");  
     digitalWrite(LED_G, LOW);  //Green LED OFF  
     delay(2000);  
     lcd.setCursor(0,0);  
     lcd.print(" Put your card   ");  
     lcd.setCursor(0,1);  
     lcd.print("              ");  
  }  
  else   
  {  
   Serial.println("CARD IS INVALID");  
    lcd.setCursor(0,1);  
    lcd.print("CARD IS INVALID   ");  
    digitalWrite(LED_R, HIGH);   // Red LED ON  
    tone(BUZZER, 300);       // Buzzer ON  
    delay(2000);  
    digitalWrite(LED_R, LOW);  
    noTone(BUZZER);  
    lcd.setCursor(0,1);  
    lcd.print("              ");  
  }  
 }  

Without I2C module

 // TECHATRONIC.COM  
 // SPI Library  
 // https://github.com/PaulStoffregen/SPI  
 // MFRC522 Library  
 // https://github.com/miguelbalboa/rfid  
 #include <SPI.h>  
 #include <MFRC522.h>  
 #include <Servo.h>  
 #include <Wire.h>   
 #include "LiquidCrystal.h"  
 LiquidCrystal lcd(A0, A1, A2, A3, A4, A5);  
 Servo s1;  
 #define SS_PIN 10  
 #define RST_PIN 9  
 #define LED_G 5  //define green LED pin  
 #define LED_R 7  //define red LED  
 #define BUZZER 6 //buzzer pin  
 MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance.  
 //Servo myServo; //define servo name  
 void setup()   
 {  
  Serial.begin(9600);  // Initiate a serial communication  
  SPI.begin();     // Initiate SPI bus  
  lcd.begin(16,2);  
  mfrc522.PCD_Init();  // Initiate MFRC522  
  s1.attach(3); //servo pin  
  // myServo.write(0); //servo start position  
  pinMode(LED_G, OUTPUT);  
  pinMode(LED_R, OUTPUT);  
  pinMode(BUZZER, OUTPUT);  
  noTone(BUZZER);  
  Serial.println("Put your card to the reader...");  
  Serial.println();  
  lcd.setCursor(0,0);  
  lcd.print(" Put your card   ");  
 }  
 void loop()   
 {  
  // Look for new cards  
  if ( ! mfrc522.PICC_IsNewCardPresent())   
  {  
   return;  
  }  
  // Select one of the cards  
  if ( ! mfrc522.PICC_ReadCardSerial())   
  {  
   return;  
  }  
  //Show UID on serial monitor  
  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.print(mfrc522.uid.uidByte[i], HEX);  
    content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));  
    content.concat(String(mfrc522.uid.uidByte[i], HEX));  
  }  
  Serial.println();  
  Serial.print("Message : ");  
  content.toUpperCase();  
  if (content.substring(1) == "5B 2F 4B 0C") //change here the UID of the card/cards that you want to give access  
  {  
   Serial.println("Authorized access");  
   Serial.println();  
     lcd.setCursor(0,0);  
     lcd.print(" CARD IS VALID      ");  
     lcd.setCursor(0,1);  
     lcd.print("Opening the Door   ");  
     digitalWrite(LED_G, HIGH); //Green LED ON  
     s1.write(0);  
     delay(3000);  
     s1.write(90);  
     lcd.setCursor(0,1);  
     lcd.print("closing the Door   ");  
     digitalWrite(LED_G, LOW);  //Green LED OFF  
     delay(2000);  
     lcd.setCursor(0,0);  
     lcd.print(" Put your card   ");  
     lcd.setCursor(0,1);  
     lcd.print("              ");  
  }  
  else   
  {  
   Serial.println("CARD IS INVALID");  
    lcd.setCursor(0,1);  
    lcd.print("CARD IS INVALID   ");  
    digitalWrite(LED_R, HIGH);   // Red LED ON  
    tone(BUZZER, 300);       // Buzzer ON  
    delay(2000);  
    digitalWrite(LED_R, LOW);  
    noTone(BUZZER);  
    lcd.setCursor(0,1);  
    lcd.print("              ");  
  }  
 }  

Please share your views and suggestions regarding this project. If you have any doubts then feel free to use the comments section below.

HAPPY LEARNING!

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