Need some suggestions about antenna MiFare RC522 13.56 MHz

Discussion in 'Wireless & RF Design' started by efel09, Aug 5, 2016.

  1. efel09

    Thread Starter New Member

    Aug 5, 2016
    1
    0
    Hello everybody, how are you doing?

    I'm developing a custom Arduino UNO board that includes a MIFARE RC522 chip. The communications between the ATMEGA328 and the RC522 seems to be working since the serial console is showing this:

    Looking for MFRC522.
    Found chip RC522 Firmware version: 0x92

    But I'm not able to read any tag. I have a RC522 shield for testing and with it I can read all my tags.

    I made some mistakes in the design of the PCB antenna. At the beginning I was having a gain of 230mV and 13.56 MHz, so my first impressions were that the strength of the signal was the problem, I made some cuts to the board and now the oscilloscope shows about 10.7V and 13.56 MHz (Wave.jpg). I don't have the expertise to know what is wrong with my design. I attached the eagle project. It's a little frustrating because my first attempt was using a PIC16@3.3v (white board of the Boards.jpg) and the board works but now with Arduino@5V with a shifter I have communication with the chip but I'm not able to read anything.

    I uploaded the Eagle files with the original design (v3) and the modified (v4, not yet tested)

    This is the sample code and tutorial I'm using https://brainy-bits.com/tutorials/card-reader-with-an-arduino-rfid-using-the-rc522-module/

    Any suggestion is appreciated

    Thanks and best regards.
    Wave.jpg Boards.jpg
     
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