Build a fake metal detector

Hello,

I need to build a fake metal detector type device for a museum installation. I am reasonably comfortable with Arduino and have used it for a handful of similar projects.

My task is to hide several sensors in the floor and build a receiver into a fake metal detector build by the props departement. Arduino should then bleep faster and faster as it gets closer to each sensor.

Can anyone suggest the correct type of sensor to use? Obviously ultrasound or infrared can't be used because they will just report the proximity of anything and everything.

Will RFID give me that kind of dynamic proximity reading?

Thanks

TomSlater: Will RFID give me that kind of dynamic proximity reading?

No.

I believe magnets + Hall sensor will give you what you want.

why nnot a real one ? - http://forum.arduino.cc/index.php?topic=65712.0

I believe magnets + Hall sensor will give you what you want.

Yes great thank you, they seem very easy to use too.