RFID Multiplexing Puzzle

Hello,

I am trying to design a puzzle where something opens when it detects several correct objects placed in their respective correct spots. I am thinking about having up to 8 separate spots that need to be filled with the correct object.

If object 1 in correct spot and if object 2 in correct spot.. .. and if object 8 is in correct spot do a certain output

The only way that I have thought of to be able to do this so far is to have multiple RFID antennae connected through a multiplexer. However, after reading through the other RFID Multiplexer questions it seems like there are voltage issues when you try to string multiple antennae together.

Does anyone on this forum have any suggestions for achieving this?

Hello, could you use weight or colour to recognise the objects?

Could the objects "plug in" somehow, i.e. make electrical contact? Then you could simply put a different resistor in each object and recognise it by measuring that.

Paul

PaulRB: Could the objects "plug in" somehow, i.e. make electrical contact?

That was the notion behind the Maxim iButton.

You may occasionally note the readers for these on security doors.

However, after reading through the other RFID Multiplexer questions it seems like there are voltage issues when you try to string multiple antennae together.

There are lots of ways to do this but connecting the antenna is not one of them. This project has 32 RFID readers each with it's own receiver coil but the exciter coil covers 8 readers.

http://www.thebox.myzen.co.uk/Hardware/RFID_Sequencer.html

You can have separate readers as in this project:- http://www.thebox.myzen.co.uk/Hardware/Crazy_People.html

Or you can use a reader with an I2C interface or an SPI interface and have several on the same bus.