I'm working with RFID RC522 using Raspberrypi 3B+. I'm following https://github.com/mxgxw/MFRC522-python this package and works like a charm. I can able to read the data from the card, able to write as well.

the problem is, this package is returing the card data as Array of strings.

 # Print UID
        print "Card read UID: %s,%s,%s,%s" % (uid[0], uid[1], uid[2], uid[3])  <== Here

The value looks like : 185,113,174,85 and I'm concatinating this array into a single string and storing it in db for further functionalities.

Now, I expecting to get the same Uid from the card by using USB based RFID Reader 13.56Mhz . But Unfortunately, the value I'm getting is not same.

The value USB RFID Reader returns 1437495737

How to rectify this. I need to get the same value for both RFID RC522 and USB based RFID Reader.

Component Details:

  • RC522 RFID - link
  • 1K RFID 13.56Mhz PVC Smart Card
  • USB Sensor Reader 14443A Proximity 13.56Mhz RFID Card Reader
  • 1
    This question doesn't seem to have anything to do with Raspberry Pi.
    – Brick
    Jun 10, 2019 at 13:41

1 Answer 1


The value 1437495737 is in hex 55ae71b9, or in little endian notation b9 71 ae 55 while the integers 185 113 174 85 are in hex also b9 71 ae 55.

So you get the same value, just in different representation.

  • thanks for the solution. It works... but I have some other doubts to clarify.. Jun 17, 2019 at 14:22

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