RFID Code for Kat

main.cpp

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

#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
boolean successfullyReadtheFirstCard = false;

boolean card1Read, card2Read, card3Read;

unsigned long LED1OnTimestamp = 0;
const int LED1Pin = 3;

const int LEDTimeLimit = 3000;

// this function checks to see if there is a card to be read (true or false)
boolean thereIsACard()
{
  // if there's a card and it can be read...
  if (mfrc522.PICC_IsNewCardPresent() && mfrc522.PICC_ReadCardSerial())
  {
    return true;
  } else { // no card was present or it couldn't be read
    return false;
  }
}

// this function returns the uppercase ID of the card being read, as a String
String returnCardID()
{
  String content = "";
  for (byte i = 0; i < mfrc522.uid.size; i++)
  {
    content.concat(String(mfrc522.uid.uidByte[i] < 0x10 ? " 0" : " "));
    content.concat(String(mfrc522.uid.uidByte[i], HEX));
  }
  content.toUpperCase();
  return content.substring(1);
}

void turnOffOldLEDs() {
  if (millis() - LED1OnTimestamp >= LEDTimeLimit) {
    digitalWrite(LED1Pin, LOW);
  }
  /*
  if (millis() - LED2OnTimestamp >= LEDTimeLimit) {
    digitalWrite(LED2Pin, LOW);
  }
  */
}

void setup()
{
  pinMode(LED1Pin, OUTPUT);
  Serial.begin(9600); // Initiate a serial communication
  SPI.begin();        // Initiate  SPI bus
  mfrc522.PCD_Init(); // Initiate MFRC522
  Serial.println("Ready");
}

void loop()
{
  // skip the rest of the loop if there isn't a card to read
  if (thereIsACard() == false)
    return;

  // read the ID of the card into the "cardID" variable
  String cardID = returnCardID();

  // print the card ID
  Serial.print("Card ID read: ");
  Serial.println(cardID);

  if (cardID == "91 D4 35 1D") {
    card1Read = true;
  }
  else if (cardID == "91 D4 35 1E") {
    card2Read = true;
  }
  else if (cardID == "91 D4 35 1F") {
    card3Read = true;
  }

  if (cardID == "74 67 0E 04" && card1Read)
  {
    Serial.println("card 1 was read, followed by card A!");
    digitalWrite(LED1Pin, HIGH);
    LED1OnTimestamp = millis();
  }

  turnOffOldLEDs();
}