detector to detect objects at close range

[zeph]

Hi, I am trying to build a metal detector that will be able to detect small objects (3mm by 20mm) at close range (1cm or less). I need the maximum diameter of the search probe/coil to be around 10 to 15mm. I was wondering if someone could recommend a circuit schematic to follow. I've looked at pulse induction and continuous wave technologies. I'm trying to detect stainless steel objects, which has a high resistivity and dissipates the eddy currents induced into the object quickly, and if using pulse induction, the frequency would need to be high. I was wondering if users on this forum can comment about the feasibility of such as small detector.

Thanks.

[zeph]

Thanks, but I think that's a little too advanced and complex for the purpose of the project I'm working on. I was thinking more along the lines of current popular technologies (pulse induction and continuous wave), and how they can be modified.

[JoAnne]

Say What?????? Good luck

[Joe(TX)]

No offense but why does everybody want to go electronic on the coin probes today! Nothing is wrong with using the old fashioned coin probes. Also it is hard to damaged them and if you do another one isn't very expensive. Of course, I was told this is because of the motion technology which makes pinpointing almost a hit or miss proposition today. In the good old days of non-motion detectors pin-pointing was never a problem!!!!! Try a Manual Coin Probe Today....................JOE