Multiple cards on one RC522

Projects General Guidance
17

This one worked well.

#include "SPI.h"
#include "MFRC522.h"

#define SS_PIN 10
#define RST_PIN 9
#define LED_PIN A0
#define LED_PIN A1

MFRC522 rfid(SS_PIN, RST_PIN);

MFRC522::MIFARE_Key key;

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
SPI.begin();
rfid.PCD_Init();
pinMode(A0, OUTPUT);
pinMode(A1, OUTPUT);
Serial.println("I am waiting for card...");
}

void loop() {
// put your main code here, to run repeatedly:
if (!rfid.PICC_IsNewCardPresent() || !rfid.PICC_ReadCardSerial())
return;

// Serial.print(F("PICC type: "));
MFRC522::PICC_Type piccType = rfid.PICC_GetType(rfid.uid.sak);
// Serial.println(rfid.PICC_GetTypeName(piccType));

// Check is the PICC of Classic MIFARE type
if (piccType != MFRC522::PICC_TYPE_MIFARE_MINI &&
piccType != MFRC522::PICC_TYPE_MIFARE_1K &&
piccType != MFRC522::PICC_TYPE_MIFARE_4K) {
Serial.println(F("Your tag is not of type MIFARE Classic."));
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();
Serial.print("Tap card key: ");
Serial.println(strID);
delay(1000);

if (strID.indexOf("89:E2:7E:CB") >= 0) { //put your own tap card key;
Serial.println("");
Serial.println("Green LED");
Serial.println("");
digitalWrite(A0, HIGH);
delay (5000);
digitalWrite(A0, LOW);
return;
}

if (strID.indexOf("9C:35:4C:23") >= 0) { //put your own tap card key;
Serial.println("");
Serial.println("Green LED");
Serial.println("");
digitalWrite(A0, HIGH);
delay (5000);
digitalWrite(A0, LOW);
return;
}

else {
Serial.println("");
Serial.println("Red LED");
Serial.println("");
digitalWrite(A1, HIGH);
delay (5000);
digitalWrite(A1, LOW);
return;
}

}