How to make a circuit to have RFID function?

[Keung]

I saw a circuit (attached) as "Reader", and using one inductor and 2 capacitors as "Tag", this can make RFID function with different LC values in "Tag".

But, I don't really understand the operation of this circuit, does anyone have experience in making and testing this kind of circuit? Can you share your experience and info.? Thanks.

I want to make a low cost RFID toy and do not want to use RFID IC, hope you can help. ;-)

 

[betwixt]

That is only part of the schematic, the oscillator, modulator and demodulators are missing.
The RFID ICs are cheap and do everything for you, serial data in, serial data out so it is false economy to try making it from discrete components.

this can make RFID function with different LC values in "Tag".

In an odd way, yes. Placing "near to oscillator frequency" tuned circuts near the inductor, providing it is driven properly will give different voltages out but distance will have as much if not more influence than LC values.

True RFID carries a command in the transmitter data and receives a response by the tag serially loading the inductors EM field, your simple circuit has no provision for doing that.

Brian.