Hi forum. I have an arduio mega with 4 RFID readers using the MFRC522 library. when I use a single reader all is good but funny things happen with multiple readers. I am sharing SPI pins and reset pin, then each reader has its own SDA pin. When, for example I have all 4 readers, readers 2, 3, 4 work great but reader 1 is unresponsive.
Any ideas?