#include <SPI.h>
#include <MFRC522.h>
#include <string.h>
 
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN);   // Create MFRC522 instance.

int emagnets = 6;
int id_skaits = 1;
const String correctIDs[5] = {"83dce51a"};

String dump_byte_array(byte *buffer, byte bufferSize) {
  String read_rfid = "";
  for (byte i = 0; i < bufferSize; i++) {
    read_rfid = read_rfid + String(buffer[i], HEX);
  }
  return read_rfid;
}

void setup() 
{
  Serial.begin(9600);
  SPI.begin();      // Initiate  SPI bus
  pinMode(emagnets, OUTPUT);
  Serial.println("Communication started");
}
void loop() 
{
  mfrc522.PCD_Init();   // Initiate MFRC522
  digitalWrite(emagnets, LOW);
  
  
  //Show UID on serial monitor
  //Serial.print("UID tag :");
  String content= "";
  byte letter;

  // If the sensor detects a tag and is able to read it
  if(mfrc522.PICC_IsNewCardPresent() && mfrc522.PICC_ReadCardSerial()) 
  {
    // Extract the ID from the tag
    content = dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
  }

  for (int i = 0; i < id_skaits ; i++) 
  {
    if(content != correctIDs[i]) {
    //Serial.print(content);
    Serial.println(" Access denied");
    return;
    }
    else {
    digitalWrite(emagnets, HIGH);
    Serial.println("Authorized access");
    Serial.println();
    delay(10000);
    }
  }

}