#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN);  
int redled = 8;
int greenled = 7;
void setup() {
  SPI.begin();     
  mfrc522.PCD_Init(); 
  pinMode(redled, OUTPUT);
  pinMode(greenled, OUTPUT);
}

void loop() {
  digitalWrite(redled, HIGH);
  // Look for new cards
  if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;
  }

  // Select one of the cards
  if ( ! mfrc522.PICC_ReadCardSerial()) {
    return;
  }

 digitalWrite(redled, LOW);
 digitalWrite(greenled, HIGH);
 delay(1000);
 digitalWrite(greenled, LOW);
 digitalWrite(redled, HIGH);
}