Sketch_01

//Viral Science
//RFID
#include <SPI.h>
#include <MFRC522.h>


#define SS_PIN 10
#define RST_PIN 9
#define LED_G 4 //define green LED pin
#define LED_R 5 //define red LED
#define LED_detect 3; //led when car detected
#define BUZZER 2 //buzzer pin
const int trigPin = 7;
const int echoPin = 6;
long duration;
int distance;
int detectCard = 0;
MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.

void setup()
{
  Serial.begin(9600);   // Initiate a serial communication
  SPI.begin();      // Initiate  SPI bus
  mfrc522.PCD_Init();   // Initiate MFRC522
  pinMode(LED_G, OUTPUT);
  pinMode(LED_R, OUTPUT);
  pinMode(LED_detect, OUTPUT);
  pinMode(BUZZER, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  noTone(BUZZER);
  Serial.println("Put your card to the reader...");
  Serial.println();

}
void loop()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration*0.034/2;



  if(distance >= 5 || distance <= 10){

    //detect car
    digitalWrite(LED_detect, HIGH);
    delay(3000);
    digitalWrite(LED_detect, LOW);


  // 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) == "D4 00 A8 1E") //change here the UID of the card/cards that you want to give access
  {
    detectCard = 1;
    noTone(BUZZER);
    digitalWrite(LED_R, LOW);
    digitalWrite(LED_G, LOW);
  }
  if(detectCard == 0){
    digitalWrite(LED_R, HIGH);
    digitalWrite(LED_G, HIGH);
    tone(BUZZER, 300);
    delay(1000);
    }
  }
  else{
    noTone(BUZZER);
    detectCard = 0;
    digitalWrite(LED_R, LOW);
    digitalWrite(LED_G, LOW);
    }
}