/*
Project: RFID RC522 module, LEDs, LCD1602 i2C module
Function: Simple security access
*/
//***************************************************************************
#include <SPI.h>//include library code for SPI comms
#include <MFRC522.h>//include library code for RFID
#include <LiquidCrystal_I2C.h> //include library code for LCD1602 I2C module
//define RFID pins
const int SS_PIN = 10;
const int RST_PIN = 9;
MFRC522 mfrc522(SS_PIN, RST_PIN);   //create MFRC522 instance.
const int redLEDpin = 8;//red LED attached to Arduino Uno digital pin 8
const int greenLEDpin = 7;//green LED attached to Arduino Uno digital pin 7
const int buzzerPin = 6;//active piezo buzzer attached to Arduino Uno digital pin 6
LiquidCrystal_I2C lcd(0x3F, 2, 1, 0, 4, 5, 6, 7, 3, POSITIVE);//initialize the library with the numbers of the interface pins
//***************************************************************************
void setup()
{
  Serial.begin(9600);   //initiate a serial communication
  SPI.begin();         //initiate SPI bus
  mfrc522.PCD_Init(); //initiate MFRC522
  pinMode(redLEDpin, OUTPUT); //sets redLEDpin as OUTPUT 
  pinMode(greenLEDpin, OUTPUT);//sets greenLEDpin as OUTPUT
  pinMode(buzzerPin, OUTPUT);//sets buzzerPin as OUTPUT
  Serial.println("Put your RFID tag close to the reader...");
  Serial.println();
  lcd.begin(16, 2);                            //16X2 lcd display
  lcd.setBacklightPin(3, POSITIVE);           //switch on the backlight
  lcd.setBacklight(HIGH);
  lcd.setCursor(0, 0);                       //setting display position
  lcd.print("  SIMPLE ACCESS  ");
  lcd.setCursor(0, 1);                       //setting display position
  lcd.print("     CONTROL   ");
  delay(2000);
  lcd.clear(); 
}
void loop()
{
  lcd.setCursor(0, 0);                       //setting display position
    lcd.print("Scan your tag or");
     lcd.setCursor(0, 1);                       //setting display position
    lcd.print("card...");
  // 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 :");
    // Sound the buzzer when a card is read
 tone(buzzerPin, 2000); 
  delay(100);        
  noTone(buzzerPin);  
  delay(100);
  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));
    lcd.clear(); 
    lcd.setCursor(0, 0);                       //setting display position
     for (byte i = 0; i < mfrc522.uid.size; i++)
  {
    lcd.print(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " ");
    lcd.print(mfrc522.uid.uidByte[i], HEX);}
  }
  Serial.println();
  Serial.print("Message : ");
  content.toUpperCase();
  if (content.substring(1) == "00 40 86 19") //change here the UID of the card/cards that you want to give access
  {    
    Serial.println("Authorized");    
    digitalWrite(greenLEDpin, HIGH);
    delay(500);
    digitalWrite(greenLEDpin, LOW);  
    lcd.setCursor(0, 1);                       //setting display position
    lcd.print(" Authorized  ");    
    delay(500);
    lcd.clear();
  }
  else   {    
    Serial.println("No access");
    digitalWrite(redLEDpin, HIGH);
    delay(500);
    digitalWrite(redLEDpin, LOW);
    lcd.setCursor(0, 1);                       //setting display position
    lcd.print("  No access  "); 
    delay(500);
    lcd.clear();
  }
}