RFID Not Found in Firmware Check

Other Hardware Sensors
1

So I watched some youtube tutorials on how to properly connect the RFID sensor to the Arduino Uno board, I installed the "rfid-master" library found here: "https://github.com/miguelbalboa/rfid" and run a firmware check to see if everything was working fine. But nothing was working fine. I got this error message:

MFRC522 Digital self test

Firmware Version: 0x0 = (unknown)
WARNING: Communication failure, is the MFRC522 properly connected?

Only known versions supported

Performing test...

Result: DEFECT or UNKNOWN

I followed the instructions on the "firmware_check.ino" sketch and it still didn't work. Maybe it has something to do with the pins on the RFID Scanner not being smoldered?

Edit: Forgot to mention I am using an "RFID-RC522" sensor and the Arduino Uno board is connected to my desktop with usb2.

2

Start by checking every connection and as you do check it against your schematic (you do have one). Be sure all grounds are properly connected. If that is correct and the voltages are correct you may have a bad scanner. The error message tells us the software cannot communicate with the MFRC522 and asking you to check the wiring. By the way if you connected it to the 5 volt supply best order another. This response is to help you get started in solving your problem, not solve it for you.
Good Luck & Have Fun!
Gil