localisation of different (hidden) objects

hi friends!

i am thinking about a project in which you have to detect different objects that are hidden under earth (just that you don't see them). you would then walk around in the garden with a device to find these objects... so how could i do this?

would 433mhz transmitter do the job? sending different pulses for each object and analyze them??

anything possible with bluetooth....x-bee....wi-fi.....could these devices give you the position of an object?

thanks for advice


What materials are you looking for?

no special materials, it's about faking objects!

i thought to bury transmitters....then make an application that shows you the buried (pseudo-) objects on a tablet...

would be nice to get distance data as well!? (you are near, getting closer...)

thanks for reply, andy

I'm having trouble visualising what you want to achieve. You could bury some sort of transponder suach as an RFID tag and do something when it is within range, but that doesn't give you any indication of distance or direction so doesn't enable your 'warm/cold' indication.

Have you considered using a plain old metal detector and just burying bits of metal?

allright, the RFID-things are looking good....

the goal is to sense the difference between the different objects, so you can distinguish between obj A and obj B, C and so on!

do you think with the metaldetector you could archieve this, for example big piece small piece, different kinds of metal?

(its about peolple going around in the garden, searching for things in the earth and that each person can find the same object in the same place with his device. devices would be something like tablet-pc+arduino+sensor)

thanks, andy