1.      INTRODUCTION

Radio Frequency Identification (RFID) is a wireless system of storing and reading data, which uses devices such as cards, Tags…

There are two types of tags:

·         Passive: Not use electrical power source because its circuit is energize by the electromagnetic waves received from the transmitter.

This type of tags not has a long range of communication (1-10cm)

·         Active: Use an electrical power source to energize its circuit, increasing range of communication with the transmitter.

2.      HOW TO CONNECT?

You can do the connections directly to the board. In this case the device used to RFID communication is RC522 Arduino module. It is energized with 3.3v.

The 3.3Vpin is connected to 3.3V on Arduino and GND to ground on Arduino. You can look the rest of connections on the following table.

Materials: ·Arduino UNO board ·Some wire Jumpers ·RFID module	RC522	ARDUINO
	3.3v	3.3v
	RST	Pin9
	GND	GND
	IRQ	-
	MISO	Pin12
	MOSI	Pin11
	SCK	Pin13
	SDA	Pin10

 

 

EXERCISE_A (Turn on a LED)

3.      PROGRAMMING

To do these exercises you have to install RC522_RFID-master library.

EXERCISE_A (READING CARDS)

#include <SPI.h>

#include <MFRC522.h>

 

#define RST_PIN  9    //Pin 9 to do reset on RC522

#define SS_PIN  10   //Pin 10 (SDA) of RC522

MFRC522 mfrc522(SS_PIN, RST_PIN); //Create the object of RC522

 

void setup() {

  Serial.begin(9600); //Initialize Serial communication

  SPI.begin();        //Initialize SPI bus

  mfrc522.PCD_Init(); // initialize created object MFRC522

  Serial.println("UID reading");

}

 

void loop() {

  //Check if exist new cards. Condition is acomplised if

  // it is true

  if ( mfrc522.PICC_IsNewCardPresent())

  {

    //Select card

    if ( mfrc522.PICC_ReadCardSerial())

    {

      // Send UID via Serial

      Serial.print("Card UID:");

      //This for loop is used to join UID terms and then print them.

      for (byte i = 0; i < mfrc522.uid.size; i++) {

        //(relational expresion) ? (expresion1) : (expresion2)

        //It is the same than a if condition

        Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");

        Serial.print(mfrc522.uid.uidByte[i], HEX);

      }

      Serial.println();

      // Finish the reading

      mfrc522.PICC_HaltA();

    }

  }

}

 

EXERCISE_B (AUTHENTICATION)

 

//Code based on http://www.naylampmechatronics.com/blog/22_Tutorial-Lector-RFID-RC522.html

 

#include <SPI.h>

#include <MFRC522.h>

 

#define RST_PIN  9    //Pin 9 to do reset on RC522

#define SS_PIN  10   //Pin 10 (SDA) of RC522

MFRC522 mfrc522(SS_PIN, RST_PIN); //Create the object of RC522

 

void setup() {

  Serial.begin(9600); //Initialize Serial communication

  SPI.begin();        //Initialize SPI bus

  mfrc522.PCD_Init(); // initialize created object MFRC522

  Serial.println("Access control: ");

}

 

byte CurrentUID[4]; //Store the code of read tag

byte User1[4] = {0xC5, 0xF6, 0x37, 0xD5} ; //code of user 1

byte User2[4] = {0xE6, 0x88, 0x44, 0x49} ; //code of user 2

void loop() {

  //Check if exist new cards. Condition is acomplised if

  // it is true

  if ( mfrc522.PICC_IsNewCardPresent())

  {

    //Select card

    if ( mfrc522.PICC_ReadCardSerial())

    {

      // Send UID via Serial

      Serial.print(F("Card UID:"));

      //This for loop is used to join UID terms and then print them.

      for (byte i = 0; i < mfrc522.uid.size; i++) {

        //(relational expresion) ? (expresion1) : (expresion2)

        //It is the same than a if condition

        Serial.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");

        Serial.print(mfrc522.uid.uidByte[i], HEX);

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

      }

      Serial.print("     ");

      //Compare the UIDs to determine if it is the UID of a user

      if (compareArray(CurrentUID, User1) || compareArray(CurrentUID, User2))

        Serial.println("Access granted...");

      else

        Serial.println("Access denied...");

 

      // Finish the reading

      mfrc522.PICC_HaltA();

 

    }

 

  }

 

}

 

//Function to compare two vectors

boolean compareArray(byte array1[], byte array2[])

{

  if (array1[0] != array2[0])return (false);

  if (array1[1] != array2[1])return (false);

  if (array1[2] != array2[2])return (false);

  if (array1[3] != array2[3])return (false);

  return (true);

}