RC522 PIN <–> ARDUINO MEGA PIN
3.3V <–> 3.3V
RST <–> D10
GND <–> GND
IRQ <–> D6
MISO <–> D50
MOSI <–> D51
SCK <–> D52
SDA <–> D9
I have some of the cheap Amazon RC522 readers, but I also have a Velleman VMA405 reader as well. The VMA405 does not use the IRQ Pin so it’s not connected to anything. I’ll have to test the RC522 without IRQ connected to see if it still works, but this pinout should work for any similar RFID readers connected to an Arduino Mega.