Eric: Are there any schematics for PI out there?

[Anonymous]

I am so happy to find this great site and I have learned much already. I was wondering if there is available any public domain schematics for a PI type machine. I want to build one for the educational value, and to see if I can understand this system a bit better. I learn by the trial and error method best! Thanks all and keep the info coming. (p.s. to Eric: You should be paid for sharing this wisdom!!! thanks for your generosity! ) BB

 

[Anonymous]

Brian,
There's a whole lot of PI circuits on the Geotechnology page by Carl Moreland.See the link below and then click on Metal Detectors and warm up your soldering iron!
Randy Seden-WD6ELU

 

[Anonymous]

Thanks again to this great forum and off I go!!! When I build, I learn!

 

[Anonymous]

Hi Brian,
I agree that Carl's Geotechnology site is the best place to go. Let us know what you build and how you get on.
Eric.

 

[Anonymous]

Thanks to all of you, I have been trying to outline the perameters of what my needs are for metal detecting. After a nugget shooting week in AZ., I feel the need for something new and viable for that hard to work soil. My thoughts are to come up with a two box device that can illuminate (ionize?) a large area say, 20'x12', possibly charging the ground with a stake system and 12v. car battery, and pulse circut. The receiver side is to be operated by hand just as one would swing a coil. I'm not sure that this idea can work with more power (gain) than what is out there now. If, the transmitter side can be separated from the receiver side, is it possible to up the output of the trans. without making the ground to overloaded to read targets? It is not actually more depth I'm after, but better separation from mineralization and hot rocks. I want to stick with PI technology with this if I can.BB

 

[Anonymous]

Brian,
What you described is called Induced Polarization. Use the Google search engine and type in Induced Polarization and also go to the IBM search engine and search the patents for IP. Hope this helps.
Randy Seden-WD6ELU
P.S. Any Amatuer Radio Operators out there want to get together on the air and have a live chat?

 

[Anonymous]

Thanks Randy, I am slowly assembling what I need to know to build this new toy. I'll give the sites and web a look-see. Just being able to read what these guys here have to say has been a big help. p.s. Randy, my late father was a pioneer in AmRadio...HS1A...Siam it was called back then, As the last of seven, I missed most of his teaching years for electronics, but maybe he is giving me a little push towards you all and your knowledge now? BB

 

[Anonymous]

Hi Brian,
One way of configuring a PI detector is to separate the TX and RX circuits so that instead of one coil, two are used. You can then make a large transmitter coil that is laid on the ground. Such a coil could be 30ft x 30ft or even bigger. A high power transmitter is used to pulse a hefty current around this coil. A small receiver coil, say 15in is used to search within the ground TX in the normal way. Such a system can go very deep indeed but is only applicable to large objects such as cannonball size and upwards. We make a detector called Superscan that uses exactly this principle. For finding small objects such as gold nuggets, the magnetic field needs to be more concentrated and also to be switched quicker than is generally possible with large coils. The Superscan uses a 24V transmitter supply but you could go much higher if you are prepared to lug big batteries around. Separating TX and RX coils does give substantially less ground signal and the DD two coil configuration as used on the Minelab SD2200 is much better than the mono coil iron mineralised ground.
Eric.