Possible to send RFID data to reader using radio frequencies?

Discussion in 'Wireless & RF Design' started by boingaon, Feb 10, 2013.

  1. boingaon

    Thread Starter Member

    May 15, 2012
    31
    0
    I'm looking to track objects around my home and business using RFID tags and a reader. I want to be able to read the tags in the objects from a greater distance than the tags are capable.

    As an experiment, I would like to make a special tag that transmits RFID information using an on-board power supply and transmitting antenna. (radio waves).

    My question is, can RFID readers pick up radio wave signals is they are tuned to the same frequency that they are intended to read? (commonly 13.56MHz or 125kHz).

    The readers function under the principle of electromagnetic induction, so I'm not sure about this.

    If it wouldn't work, is there any way to boost the original tag using on-board power to extend the transmit range to about 10 feet?

    Thanks
     
  2. jaygatsby

    New Member

    Nov 23, 2011
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    Read, remodulate, reuse.
     
  3. boingaon

    Thread Starter Member

    May 15, 2012
    31
    0
    Thank you, but I'm really looking to answer one important question - can a reader equipped with an inductive transmitter/receiver pick up signals from a tag that sends data using radio waves?

    Or, another option would be to use a conventional inductive antenna on the tag, but power it up to improve the range.
     
  4. jaygatsby

    New Member

    Nov 23, 2011
    185
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    I don't think that the tag sends data constantly. The reader powers it when it is close to it.
     
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    How large would you want the tag?

    A coin cell can send in pulses for short periods (think keyfob remote door locks).

    It will need a sizeable amount of support circuitry, so that no power is drawn until triggered by the RFID field it is sending to.
     
  6. WBahn

    Moderator

    Mar 31, 2012
    17,743
    4,790
    I think you have a number of problems to contend with. As you say, most RFID is done inductively so essentially you have an air core transformer and what the reader is sensing is whether the load is light or heavy. So the reader is essentially sensing how much power the tag is pulling from it, synchronized to the reader's waveform. So your long-distance tags would have to mimick that effect. Now, I believe their are active RFID systems that would be more suitable for this.

    Then, as tags get further away from each other you will have increased problems with self-jamming and the potential for hidden node problems.
     
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