#include SPI.h
#include MFRC522.h
#define SS_PIN 10
#define RST_PIN 9
int flag=0;
int op=8;
char UID[] = XXXXXXXX;            Place your UID of your tag here.
MFRC522 rfid(SS_PIN, RST_PIN);
MFRC522MIFARE_Key key;
void setup()
{
Serial.begin(9600);
SPI.begin();
rfid.PCD_Init();
pinMode(op,OUTPUT);
}
void loop()
{
if ( ! rfid.PICC_IsNewCardPresent())
return;
if ( ! rfid.PICC_ReadCardSerial())
return;
MFRC522PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
if(piccType != MFRC522PICC_TYPE_MIFARE_MINI &&
piccType != MFRC522PICC_TYPE_MIFARE_1K &&
piccType != MFRC522PICC_TYPE_MIFARE_4K) {
Serial.println(F(Your tag is not of type MIFARE Classic, your tag can't be read ());
return;
}
String StrID =  ;
for (byte i = 0; i 4; i ++)
{
StrID +=
(rfid.uid.uidByte[i]0x10 0  )+
String(rfid.uid.uidByte[i],HEX)+
(i!=3   );
}
StrID.toUpperCase();
if(StrID!=UID)
{
Serial.println(This is an invalid tag ();
Serial.println();
delay(2000);
}
if (StrID==UID && flag==0)
{
flag=1;
digitalWrite(op,HIGH);
Serial.println(This is a vaild tag ));
Serial.println(Status ON);
Serial.println();
delay(2000);
}
else if(StrID==UID && flag==1)
{
flag=0;
digitalWrite(op,LOW);
Serial.println(This is a vaild tag ));
Serial.println(Status OFF);
Serial.println();
delay(2000);
}
rfid.PICC_HaltA ();
rfid.PCD_StopCrypto1 ();
}