3.3v = 3V
RST = D1
GND = G
MISO = D6
MOSI = D7
SCK = D5
SDA = D2
==============================================
#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN D1
#define SDA_PIN D2

MFRC522 mfrc522(SDA_PIN, RST_PIN);

void setup() {
  Serial.begin(9600);
  SPI.begin();
  mfrc522.PCD_Init();
  Serial.println("Put your card to the reader...");

}

void loop() {
  if(!mfrc522.PICC_IsNewCardPresent()){
    return;
  }

  if(!mfrc522.PICC_ReadCardSerial()){
    return;
  }

  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("Pesan : ");
  content.toUpperCase();

  if(content.substring(1) == "D9 DF 60 B9"){
    Serial.println("Kartu cocok");
    Serial.println();
    delay(1000);
  }

  else if(content.substring(1) == "79 D0 24 A3"){
    Serial.println("Kartu cocok");
    Serial.println();
    delay(1000);
  }

  else{
    Serial.println("Kartu Tidak cocok");
    delay(1000);
  }

}


===============================================

#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN D1
#define SDA_PIN D2

MFRC522 mfrc522(SDA_PIN, RST_PIN);

void setup() {
  Serial.begin(9600);
  SPI.begin();
  mfrc522.PCD_Init();
  Serial.println(" RFID Reading UID");

}

void loop() {

  if ( mfrc522.PICC_IsNewCardPresent())
      {
        if ( mfrc522.PICC_ReadCardSerial())
        {
          Serial.print("Tag UID:");
          for (byte i = 0; i , mfrc522.uid.size; i++) {
            Serial.println(mfrc522.uid.uidByte[i] <0x10 ? "0":" ");
            Serial.println(mfrc522.uid.uidByte[i], HEX);
          }
          Serial.println();
          mfrc522.PICC_HaltA();
        }
      }
}