Detecting a small object in space.

[NewSkol]

Hello,

Unfortunately I am not very proficient in physics, however I got very curious in regards to detecting an object (For the matter of argument let us use a metal object that would be the size range of about 0.5-1cm3) in 3D space.

I am not sure what would be the best way to even start thinking about it?

Radar, Lidar, Electromagnets (The object can contain a magnet), Radio transmitters.

I would like to be able to detect this object rather accurately and I would need to be able to track it. What do you think would the best technology to use be? I am looking for something simple, fast and cheap. (Thus I don't think I want to use cameras, but that would probably be easiest at this point).

Any ideas? Thanks in advance.

 

[schip666!]

How much space?

 

[NewSkol]

Lets say for example 25cm x 25cm x 25cm.

 

[schip666!]

For just detecting an object in a 1 foot cube I might go with magnets and metal detectors.

If you want the position as well, then...hmmmm... I wonder if you could use an RFID chip in your object and some _really_ directional antennas. Or some kind of phase detector for the radio signal. Radar kinda stuff would need fully absorptive walls (if it's a container we are talking about) and a very fast response time -- 1ns per foot. A couple cheap web-cams might be your best option. There's open-source position detecting software for images out there.