Hello guys,
I've got a problem I can't solve. 
I connected a RFID-reader with Arduino Nano, so I can read the Cards UID with the Serial Monitor.
My code:
#include <SPI.h>
#include <MFRC522.h>
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN); // Create MFRC522 instance.
void setup() {
Serial.begin(9600); // Initialize serial communications with the PC
SPI.begin(); // Init SPI bus
mfrc522.PCD_Init(); // Init MFRC522 card
Serial.println("Scan PICC to see UID and type...");
}
void loop() {
// Look for new cards
if ( ! mfrc522.PICC_IsNewCardPresent()) {
return;
}
// Select one of the cards
if ( ! mfrc522.PICC_ReadCardSerial()) {
return;
}
// Dump debug info about the card. PICC_HaltA() is automatically called.
mfrc522.PICC_DumpToSerial(&(mfrc522.uid));
}
The output on the serial monitor with the code above looks like:
Scan PICC to see UID and type...
Card UID: 1B F0 76 41
Card SAK: 08
PICC type: MIFARE 1KB
Sector Block 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 AccessBits
15 63 00 00 00 00 00 00 FF 07 80 69 FF FF FF FF FF FF [ 0 0 1 ]
62 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 0 0 0 ]
61 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 0 0 0 ]
60 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 [ 0 0 0 ]
14 59 PCD_Authenticate() failed: Timeout in communication.
13 55 PCD_Authenticate() failed: Timeout in communication.
12 51 PCD_Authenticate() failed: Timeout in communication.
etc.
The problem now is, that I only need the Card UID to be outputed. I thought about string-functions, but I don't know how exactly they work or if the problem can even be solved using them.
Moreover it would be very good if the problem got solved today. 
P.S.:
There are more cards, so I can't output a given code. I need to take the code which the RFID-card has.
I would really appreciate it if anyone could help me.
Thx a lot! 