Arduino RFID Door Lock Access Control Project

We will learn what RFID is, how it works and how to make an Arduino based RFID door lock

MFRC522 RFID module

Servo motor

LCD display

Arduino Board

Breadboard and jumper wires

Proximity sensor

First we have to set up a master tag, then the system goes into normal mode. If we scan an unknown tag, access will be denied, but if we scan the master, we will go into program mode from where we can add and authorize unknown tags. So now if we scan the tag again, access will be granted so we can open the door. After we close the door, it will automatically lock. If we want to remove a tag from the system, we just need to go into program mode again, scan the know tag, and it will be removed.

Now let's take a look at the code. So first we need to include the libraries for the RFID module, display and servo motor, define some variables required for the following program and create an instance of the library.

This is the complete code of the project,

/*

* Arduino Door Lock Access Control Project

*         

* by Dejan Nedelkovski, www.HowToMechatronics.com

* 

* Library: MFRC522, https://github.com/miguelbalboa/rfid

*/

#include <SPI.h>

#include <MFRC522.h>

#include <LiquidCrystal.h>

#include <Servo.h>

#define RST_PIN  9

#define SS_PIN  10

byte readCard[4];

char* myTags[100] = {};

int tagsCount = 0;

String tagID = "";

boolean successRead = false;

boolean correctTag = false;

int proximitySensor;

boolean doorOpened = false;

// Create instances

MFRC522 mfrc522(SS_PIN, RST_PIN);

LiquidCrystal lcd(2, 3, 4, 5, 6, 7); //Parameters: (rs, enable, d4, d5, d6, d7)

Servo myServo; // Servo motor

void setup() {

 // Initiating

 SPI.begin();    // SPI bus

 mfrc522.PCD_Init(); // MFRC522

 lcd.begin(16, 2);  // LCD screen

 myServo.attach(8); // Servo motor

 myServo.write(10); // Initial lock position of the servo motor

 // Prints the initial message

 lcd.print("-No Master Tag!-");

 lcd.setCursor(0, 1);

 lcd.print("  SCAN NOW");

 // Waits until a master card is scanned

 while (!successRead) {

  successRead = getID();

  if ( successRead == true) {

   myTags[tagsCount] = strdup(tagID.c_str()); // Sets the master tag into position 0 in the array

   lcd.clear();

   lcd.setCursor(0, 0);

   lcd.print("Master Tag Set!");

   tagsCount++;

  }

 }

 successRead = false;

 printNormalModeMessage();

}

void loop() {

 int proximitySensor = analogRead(A0);

 // If door is closed...

 if (proximitySensor > 200) {

  if ( ! mfrc522.PICC_IsNewCardPresent()) { //If a new PICC placed to RFID reader continue

   return;

  }

  if ( ! mfrc522.PICC_ReadCardSerial()) {  //Since a PICC placed get Serial and continue

   return;

  }

  tagID = "";

  // The MIFARE PICCs that we use have 4 byte UID

  for ( uint8_t i = 0; i < 4; i++) { //

   readCard[i] = mfrc522.uid.uidByte[i];

   tagID.concat(String(mfrc522.uid.uidByte[i], HEX)); // Adds the 4 bytes in a single String variable

  }

  tagID.toUpperCase();

  mfrc522.PICC_HaltA(); // Stop reading

  correctTag = false;

  // Checks whether the scanned tag is the master tag

  if (tagID == myTags[0]) {

   lcd.clear();

   lcd.print("Program mode:");

   lcd.setCursor(0, 1);

   lcd.print("Add/Remove Tag");

   while (!successRead) {

    successRead = getID();

    if ( successRead == true) {

     for (int i = 0; i < 100; i++) {

      if (tagID == myTags[i]) {

       myTags[i] = "";

       lcd.clear();

       lcd.setCursor(0, 0);

       lcd.print(" Tag Removed!");

       printNormalModeMessage();

       return;

      }

     }

     myTags[tagsCount] = strdup(tagID.c_str());

     lcd.clear();

     lcd.setCursor(0, 0);

     lcd.print("  Tag Added!");

     printNormalModeMessage();

     tagsCount++;

     return;

    }

   }

  }

  successRead = false;

  // Checks whether the scanned tag is authorized

  for (int i = 0; i < 100; i++) {

   if (tagID == myTags[i]) {

    lcd.clear();

    lcd.setCursor(0, 0);

    lcd.print(" Access Granted!");

    myServo.write(170); // Unlocks the door

    printNormalModeMessage();

    correctTag = true;

   }

  }

  if (correctTag == false) {

   lcd.clear();

   lcd.setCursor(0, 0);

   lcd.print(" Access Denied!");

   printNormalModeMessage();

  }

 }

 // If door is open...

 else {

  lcd.clear();

  lcd.setCursor(0, 0);

  lcd.print(" Door Opened!");

  while (!doorOpened) {

   proximitySensor = analogRead(A0);

   if (proximitySensor > 200) {

    doorOpened = true;

   }

  }

  doorOpened = false;

  delay(500);

  myServo.write(10); // Locks the door

  printNormalModeMessage();

 }

}

uint8_t getID() {

 // Getting ready for Reading PICCs

 if ( ! mfrc522.PICC_IsNewCardPresent()) { //If a new PICC placed to RFID reader continue

  return 0;

 }

 if ( ! mfrc522.PICC_ReadCardSerial()) {  //Since a PICC placed get Serial and continue

  return 0;

 }

 tagID = "";

 for ( uint8_t i = 0; i < 4; i++) { // The MIFARE PICCs that we use have 4 byte UID

  readCard[i] = mfrc522.uid.uidByte[i];

  tagID.concat(String(mfrc522.uid.uidByte[i], HEX)); // Adds the 4 bytes in a single String variable

 }

 tagID.toUpperCase();

 mfrc522.PICC_HaltA(); // Stop reading

 return 1;

}

void printNormalModeMessage() {

 delay(1500);

 lcd.clear();

 lcd.print("-Access Control-");

 lcd.setCursor(0, 1);

 lcd.print(" Scan Your Tag!");

}