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Topic: How do RFID tags work? (Read 504 times) previous topic - next topic

123Splat

Feb 25, 2013, 09:23 pm Last Edit: Feb 25, 2013, 09:44 pm by 123Splat Reason: 1
In the Project Guidance tab there is a wonderful thread (AWOL locked it just when it was getting fun), by some fellow who wanted to use an Arduino to generate jamming signals around 100MHz.  It is a real fun read.  

Anyway, in a discussion of various things that the FCC could and couldn't regulate, this guy brings up RFID tags.  The response by a knowledgable member was that RFID tags operated in an unrestricted Freq. band.

My understanding is that the FCC pretty much only cares about emmisions, and I thought that RFID tags did not emit anything, they just caused resonance or disturbance in a detecting field (something like beat freq in a metal detector). I know I'm old and feable,but Did I miss something in how the tagd work?

AWOL

Please tone down the personal attacks.
Glass houses, and all that.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Grumpy_Mike

Some RFID tags take in power at one frequency and use it to power a transmitter at another. This is how the 13MHz tokens work. Most of the 125KHz tokens work with inductive coupling like you thought.

123Splat

AWOL:  Sorry, I believe I have corrected the offending language.

Grumpy:  Thanks.  Just goes to show how far in the past I live.  Time to do more research......

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