I have having a problem designing an rfid receiver that can read from 4 antenais that can be controlled from the micro at any given time. Let me explain, I need to have 4 coils that can be switched to 1 rfid reader or circuit. I have found some circuit from microhip but nothing on switching between coils.
OK maybe a little explaination of what I am trying to do.
I have 4 coils going small to large and all in a center on top of each other.
Now I take a PUK and out a rfid in in, I slide the puk on top a table to circles.
Now I can scan each cicrle to see where the puk landed.
Hope this helps..
So bascailly need to do 1 reader to scan 4 coils, it is for a game to tally the scores automatically. I may have 5th coil for outehr of table to detect out of zone.
Please any help wouyld be great, will be costly if have to do 4 or 5 readers.
We used 4051 analog multiplexors to design 40 inputs RFID and all they work well. Single U2270B chip is connected through 5 analog multiplexors 4051 to 40 different coils. We used ferrite inductors 5x10 750uH which could be obtained in any electronic shop. The detect distance was around 30mm.
I'm talking about working solution, so 4051 is the way to extend the number of channels.
Thank you for your input, I am looking at the microchip design circuit so will I use the 4051 on both sides of the coil? Or should it be used somewhere else in the circuit?
You didn't tell about the RFID type (125 kHz, 13.56 MHz, ...) or reader chip. Some circuits probably work with a low voltage multiplexer like 4051, others won't.
BTW, the voltage on the coil could reach 15-20V if the componets were properly adjusted. You should not be fooled from the fact that 4051 uses 5V Vcc, the voltage on the coil is definetely higher than 5V.
Similar schematic with 40 readers can scan 40 different RFID tags within 2s if the reading process was optmized.