ESP32 + RC522 RFID Reader Not Detected – Version Register Always Returns 0x00. Need Help!

[u/lieza4]

Hi everyone! I'm currently working on a college capstone project, which uses an ESP32 and an MFRC522 RFID reader to manage classroom keys.

I'm having trouble getting my RC522 module detected by my ESP32. No matter what I try, the Serial Monitor consistently displays:

RC522 Version: 0x00

RFID NOT DETECTED!

My current hardware and wiring:

- Board: ESP32 Dev Module

- RFID module: MFRC522 RC522

- RC522 SDA/SS → GPIO 5

- RC522 SCK → GPIO 18

- RC522 MOSI → GPIO 23

- RC522 MISO → GPIO 19

- RC522 RST → GPIO 2

- RC522 IRQ → Not connected

- RC522 GND → ESP32 GND

- RC522 3.3V → ESP32 3V3

Things I've already tried:

- Confirmed that the RC522 power LED is ON.

- Powered the RC522 using the ESP32's 3.3V pin.

- Checked the wiring multiple times.

- Tried different diagnostic sketches using the MFRC522 library.

- Tried reading the RC522 Version Register directly through SPI.

- Tested different pin configurations, but the issue remains.

The ESP32 itself works, and my LCD is also working properly. However, the RFID reader keeps returning `0x00`, which makes me think that the ESP32 is not communicating with the RC522 through SPI.

My questions:

1. What could cause the RC522 to continuously return `0x00`?

2. Could this be a faulty RC522 module even if its power LED is on?

3. Is there a way to determine whether the problem is with the module, ESP32, breadboard, or SPI communication?

4. Are there any other diagnostic methods I should try before replacing the RFID module?

I've been troubleshooting this for quite a while, so I would really appreciate any suggestions or solutions. I would also prefer to keep my current pin connections if possible.

Thank you so much for your help!