Whats happening with DIY Pulse Induction MDs? How about software based MDs?

[Functional]

Whats happening with DIY Pulse Induction MD's? How about software based MD's?

PI MD's

I've been hunting around the web and this forum and I've seen several plans for Pulse Induction MD's, some dating back a couple of decades, but has anyone actually field tested any of these? Have any comparisons been done to tell which is best, or at least which works in real world conditions and not just in air tests, or in someones back yard? Do any of them have descrimination that would allow them to work as nugget hunters in highly mineralized soil, or in salt water, (or some combination of both), while still being able to find; silver, gold and platinum?

There are several plans here, but I can't tell which works, or how well:
http://geotech.thunting.com/cgi-bin/pages/common/index.pl?page=metdet&file=projects.dat

I'm no electronics guru and not being rich enough to afford to gamble on a new commercial PI MD, (that may, or may not do what I need), I'm more interested in a project / kit, that is realtively easy to assemble. I'm pretty good at soldering automotive stuff, but haven't done much electronics.

I saw a kit here:
http://home.global.co.za/~trh/
But, I don't know much about the person offering it and payment by PayPal just doesn't work for me. If I can't mail a money order to a physical address, in either Canadian, or U.S. funds, then I'm not sending anything.


Software based PI MD's

Has anyone looked into using a portable computing device, like a Palm Pilot, or something similar, as the basis of a PI MD? I know theres freeware software like Snuffler that could be used with a laptop as a base to do all the signal processing and provide actual 2D imaging when used with things like GPR. I wonder if it might be adapted to this type of use to give an "ultrasound" type of view, of what lies beneath a PI, or other type of MD? (Short of actually using ultrasound.) Maybe the combination of something like PI and microwave, or millimeter wave technology would make for an all around great MD?

I'm just throwing around some ideas, but if anyone else has some insights to offer, feel free to add them. I know, its past 3AM and I'm feeling kind of punchy, so I'll leave off here for now.

F.

 

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[Willy]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

If you cruise through the Geotech forums you'll probably get a good idea as to how the DIY detectors fare. You'll also see that it's a helluva lot of work to get them working properly.. even with an electronics background. Another problem faced when building a simple PI is the intended application. Some will do well for water hunting, but get them on dry mineralized land and it's a different story. When it comes to programmable PI's, there's the required code to obtain (and load correctly) and the interface.. which can be pricey. After all is said and done, you're probably much better off buying a commercially produced detector than building one. Can you imagine trying to repair a DIY detector that's malfunctioning? With one that's bought, you just send it off to get repaired. ...Willy.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

If you cruise through the Geotech forums you'll probably get a good idea as to how the DIY detectors fare. You'll also see that it's a helluva lot of work to get them working properly.. even with an electronics background. Another problem faced when building a simple PI is the intended application. Some will do well for water hunting, but get them on dry mineralized land and it's a different story. When it comes to programmable PI's, there's the required code to obtain (and load correctly) and the interface.. which can be pricey. After all is said and done, you're probably much better off buying a commercially produced detector than building one. Can you imagine trying to repair a DIY detector that's malfunctioning? With one that's bought, you just send it off to get repaired. ...Willy.

I'm just throwing ideas out there for those far more knowledgable than I, in electronics and MD's generally. As you said, I'll likely end up getting a used MD, but I'll also keep my options open for something better at a later date, should someone work out a way of providing an affordable and more capable PI MD.

Some of the information I've found relating to pulse induction, has actually come from websites relating to robotics and mine locating, like this one:
http://www.icti.ir/iutmicrobot/deminer.html

Or archeological related software like on these websites:
http://www.geology.ohio-state.edu/~jeff/software.htm
http://www.nd.edu/~mschurr/nddown/index.html

I've looked at GPR and a few other subsurface locator/imaging techniques and find them interesting. But at the same time, from what I've seen, I wonder if others have thought of alternatives, like MD's with one transmit loop and two or more receiver loops, to use for obtaining 2D, or 3D images. Or a simple "two box" based on a disassembled coil, using the two loops instead of the common rectangular transmit and receive loops used on the two box MD's. I've been reading up on coil design, but I'm no guru in this area either.

Anyway, I would be interested in finding one DIY pulse induction MD that has "commercial" capabilities, if anyone eventually develops one that a non-electronics type person can assemble and program. And if its too complex for the average MD'er to assemble form schematics, then maybe the person who designed it could have small lots, of portions of the MD, made in China, or elsewhere, for later programming and assembly in North America, (or wherever they choose). Distributing a good PI MD, for later (partial), assembly at home, would seem to be a cheaper way of getting them out there to the masses, (so long as the assembly instructions were better than Ikea's ).

Who knows, maybe someone could come up with a simple way of modifying one of those cheapo, made in China MD's that are all over eBay, so that they perform like they were made for the real world? I know theres a dozen, or so different models from assorted Chinese companies, but I've never owned one and I don't know of anyone who admits to owning one. Or at least nobody who has spoken highly of any of them.

Just a thought, or two to mull over.

F.

 

[Rob in KS]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I just finished building Carl's Hammer Head PI. A commercial one is REALLY out of my price range, so this was the best route for me. I'm pretty pleased with the results. There is a lot of good info on the Geotech forum. The folks over there are willing to help.

I had a few problems getting it to work right. I have a background in electronics. It's quite a project for someone without at least some electronics experience. An oscilloscope is a must have for the project.

I bought 2 of Carl's circuit boards. I built one using the original schematic. I'm going to build the second one with a microprocessor to control the timing and read the signal. There is a guy on Geotech developing a universal computer for use with PI detectors. Its intended to allow experimenting without having to do any programming.

I read that there are some discriminating PIs comming out soon.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I just finished building Carl's Hammer Head PI. A commercial one is REALLY out of my price range, so this was the best route for me. I'm pretty pleased with the results. There is a lot of good info on the Geotech forum. The folks over there are willing to help.

Does it seem to work well in mineralized soil? I can relate to the price of a commercial PI. Unless I could pay for a made in China version.

I had a few problems getting it to work right. I have a background in electronics. It's quite a project for someone without at least some electronics experience. An oscilloscope is a must have for the project.

I've soldered a Chev, but I don't think that qualifies me. I did find a cool program, (I think its freeware), that turns your computer into an oscilliscope. Not sure how it interfaces as far as input to the computer though.

I bought 2 of Carl's circuit boards. I built one using the original schematic. I'm going to build the second one with a microprocessor to control the timing and read the signal. There is a guy on Geotech developing a universal computer for use with PI detectors. Its intended to allow experimenting without having to do any programming.

I've done some programming, but not many people use xBasic, (at least not alot that admit it, even though its a good programming environment), but I'm to say the least, a little rusty at it.

I read that there are some discriminating PIs comming out soon.

I've seen some references to commercial discriminating PI's, but not much in the DIY area. I'll be poking around some in the Geotech forum and see what I can gleen from all the techie types there. Sure wish I had some of the MD's and related toys to play with here. I might find something interesting, even if I didn't know what it was.

F.

 

[Rob in KS]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

Does it seem to work well in mineralized soil? I can relate to the price of a commercial PI. Unless I could pay for a made in China version.

We don't have mineralization here, or many beaches so I can't say. I understand that they test them in Oz where the mineralization is terrible. They do quite well.

I've soldered a Chev, but I don't think that qualifies me. I did find a cool program, (I think its freeware), that turns your computer into an oscilliscope. Not sure how it interfaces as far as input to the computer though.

There is some hardware that plugs into the USB port and turns your PC into a scope. There are some scopes on ebay that are relative inexpensive.

I've done some programming, but not many people use xBasic, (at least not alot that admit it, even though its a good programming environment), but I'm to say the least, a little rusty at it.

Basic might be too slow, things happen fast in a PI. The guy making a generic computer is trying to eliminate programming yet still give you the ability to experiment.

I've seen some references to commercial discriminating PI's, but not much in the DIY area. I'll be poking around some in the Geotech forum and see what I can gleen from all the techie types there. Sure wish I had some of the MD's and related toys to play with here. I might find something interesting, even if I didn't know what it was.

I don't think you'll see a DIY discriminating PI. Its a pretty tough problem. If I did it, I would want to make some money on it. I can only imagine how many hours went into Carl's design. Just laying out the circuit board takes HOURS. Not to mention the hours of experimenting. There are 5 or 6 designs on Geotech by different people.

I got started in this when a guy found a huge meteorite in Kansas. He used a PI with a 8' by 12' coil towed behing an ATV. The meteorite was 7 1/2 feet deep!!! Its worth a million!!
http://www.meteorite-times.com/Back_Links/2006/February/Meteorite_People.htm

This had been my main goal in metal detecting. I probably won't find any colonial coppers here, no gold, not even any real old relics. Lots of 20th century rusty iron

 

[Willy]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

As I told a buddy that wanted to hunt for buried pirate treasure on the East coast (Harr! Me matey.. HARRR!) with a 2 box.. finding it is all fine and good, but actually digging it up? Can you imagine finding a tire rim down 8 ft in the sand and then having to move all that material to get down there? Makes me shudder just thinking about it. ..Willy.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I've done some programming, but not many people use xBasic, (at least not alot that admit it, even though its a good programming environment), but I'm to say the least, a little rusty at it.

Basic might be too slow, things happen fast in a PI. The guy making a generic computer is trying to eliminate programming yet still give you the ability to experiment.


xBasic is a cross platform programming language, with xBLite being a windows version, (both are freeware). Both are compiled and basically the runtime programs are up there with C++ and other languages.

But the programming language I think would best suited to building both analog and digital MD's is one I can't remember. It's a version of basic put out by an electronics company in England, for programming microcontrollers. When compiled, it creates both assembly and machine language files. I think I would remember the name if I saw it again, but it just eludes me at the moment. I do remember I tried to download it a few times, but I'm on dialup and it kept timing out on me. The file size was about 45 Mb's and I'd get about 7 Mb's when it would time out.


I had to modify this to mention that I finally remembered which software that was I was thinking of. It was a program called PicAxe, (current version is 27 Mb's), available here:
http://www.rev-ed.co.uk/picaxe/

They also mention some other third party software, but from what I recall, (after having done a few searches), theres another programming language for PIC controllers, (thats open source), called Great Cow Basic available here:
http://gcbasic.sourceforge.net/index.html

Just thought I'd mention this for anyone interested in programming IC's.


I've seen some references to commercial discriminating PI's, but not much in the DIY area. I'll be poking around some in the Geotech forum and see what I can gleen from all the techie types there. Sure wish I had some of the MD's and related toys to play with here. I might find something interesting, even if I didn't know what it was.


I don't think you'll see a DIY discriminating PI. Its a pretty tough problem. If I did it, I would want to make some money on it. I can only imagine how many hours went into Carl's design. Just laying out the circuit board takes HOURS. Not to mention the hours of experimenting. There are 5 or 6 designs on Geotech by different people.

I got started in this when a guy found a huge meteorite in Kansas. He used a PI with a 8' by 12' coil towed behing an ATV. The meteorite was 7 1/2 feet deep!!! Its worth a million!!
http://www.meteorite-times.com/Back_Links/2006/February/Meteorite_People.htm

This had been my main goal in metal detecting. I probably won't find any colonial coppers here, no gold, not even any real old relics. Lots of 20th century rusty iron

I wouldn't mind getting my hands on a discriminating PI MD, but if I can't find one at a price within my budget, (which seems to be the case), then I'm wondering if I can find a non-PI MD with really good discrimintation, that could be made into a two box, or some simple (and cheap) DIY equivalent.

I've out a couple of posts on GeoTech along these lines:
http://thunting.com/geotech/forums/showthread.php?t=12888
http://thunting.com/geotech/forums/showthread.php?p=52549#post52549

I don't know if anything will come of them, but lifes a learning process, (too bad it takes some of us, (meaning me), longer to learn though).

Anyway, its time for nuked leftovers, so I'll be off for now.

F.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

As I told a buddy that wanted to hunt for buried pirate treasure on the East coast (Harr! Me matey.. HARRR!) with a 2 box.. finding it is all fine and good, but actually digging it up? Can you imagine finding a tire rim down 8 ft in the sand and then having to move all that material to get down there? Makes me shudder just thinking about it. ..Willy.

Hey Willy!

In my other post to the GeoTech forum, I speculate on using different sized loops on a two box and the possible effect this might have on widening the coverage area while decreasing its depth. I'm not sure if it would work, but I thought I'd see if anyone in that forum would know. My post is here:
http://thunting.com/geotech/forums/showthread.php?t=12888

(If all else fails, maybe hold the two box elevated 6 feet above ground. )
Ok, I said this in my other post, so now its really time to go for supper.

F.

 

[Rob in KS]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

Hey Functional
Maybe you should try to build the hammer head. From your posts on geotech, it sounds like you know more than it sounded like on here. You asked some good questions.

I'm going to go ahead and build my second board for a 1m coil without the microprocessor. That way I can get out and use it instead of getting bogged down in programming and stuff. Maybe next winter I'll convert it to use a microprocessor.

I got a lot of the parts from Digikey.

I built a 10" coil and it can detect my BBQ grill at about 2.5 to 3 feet. It could be better, I didn't use the best wire, just the wire I had. Coil building is a whole subject in itself

You'll sure learn a lot building it..... I did

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

Hey Functional
Maybe you should try to build the hammer head. From your posts on geotech, it sounds like you know more than it sounded like on here. You asked some good questions.

Thanks, I'm great at asking questions. Not so great at getting answers sometimes though.

I'm going to go ahead and build my second board for a 1m coil without the microprocessor. That way I can get out and use it instead of getting bogged down in programming and stuff. Maybe next winter I'll convert it to use a microprocessor.

I wonder if those guys building the PI's shouldn't get together with that other person doing the microprocessor addon and design they're boards with some sort of plug-in interface in mind?

I got a lot of the parts from Digikey.

I've been following the HH threads as best I can, but I've found the list of parts needed seems to fluctuate somewhat. It sure would be nice if someone used software with a BOM (Bill Of Materials) feature and where there was some flexibility in the circuitry, like options to use one resister, or capacitor over another, just show that as an option. Would make pricing out the parts easier also.

I posted several links in the General Electronics area for DIY stuff, (CAD, CAM, PCB, software, electronics test equipment schematics, etc). I also have some more to add relating to BOM software for those that use Eagle, but I was going to wait and see what else I run across before doing a followup post. You can find the software here:
http://www.cadsoft.de/cgi-bin/downl...blic/download.htm.en&dir=eagle/userfiles/misc

I built a 10" coil and it can detect my BBQ grill at about 2.5 to 3 feet. It could be better, I didn't use the best wire, just the wire I had. Coil building is a whole subject in itself

You'll sure learn a lot building it..... I did

I downloaded a program called Digital Simulator V5.57, (27 Mb's on dialup takes about 90 minutes if the ISP doesn't disconnect me, just for fun), and I've seen at least one other program that is supposed to be for those like myself, who are electronically challenged, so I think I'll grab it when I find it again. The price seems right on for the bare board, but I still don't know what the end cost would be? I don't have much of a budget to work with at the moment. I'll be weighing my options though.

F.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I built a 10" coil and it can detect my BBQ grill at about 2.5 to 3 feet. It could be better, I didn't use the best wire, just the wire I had. Coil building is a whole subject in itself

You'll sure learn a lot building it..... I did

I forgot to mention that I still have my old MD's and was thinking that if I were to build a PI MD, I could gut one, or both old MD('s) and slide the new PI innerd's inside. Might keep the PI from being stolen. Who would want to steal one of these?

I modified this post to remove the pictures of my MD's as it slowed down the loading of the page. No real need to have them here now anyway as most have seen them.

I wonder if I could use one of my old coils too?

As for air detecting a BBQ, I think I can manage that without an MD.
Depending on whats on the barbie and on the wind speed and direction, I can usually detect it within a 100' or so. If only I could do that with gold.

F.

 

[Rob in KS]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

That's a great idea using those old detectors. You would have a lot of the mechanical stuff already done. Even if you couldn't use the existing coil, you could use the coil shell. And nobody would steal it.

The other ideas you have are good too. Re-layout the Hammer head board so that it plugs into the guy's processor board. Super idea. Now if someone had the time to do it. Any volunteers

Oh yes, about the barbie....smell this....I hope it animates for you

http://www.wildflower.net/robkelly/grilling.gif

I throw a little apple wood on it right before I put on the chops....MMMMMM good

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

That's a great idea using those old detectors. You would have a lot of the mechanical stuff already done. Even if you couldn't use the existing coil, you could use the coil shell. And nobody would steal it.

I wouldn't even have to drill a hole for the speaker, headphone jack, or the one on/off tuning knob. Man, I really can be lazy at times.

The other ideas you have are good too. Re-layout the Hammer head board so that it plugs into the guy's processor board. Super idea. Now if someone had the time to do it. Any volunteers

I vote for you to oversee the implementation and adaptation of the microprocessor circuit to all PI's.

Oh yes, about the barbie....smell this....I hope it animates for you

http://www.wildflower.net/robkelly/grilling.gif

How did you get my drill press?
At least you put plastic over it. I usually keep it in the shed/workshop under lock and key.

I throw a little apple wood on it right before I put on the chops....MMMMMM good

Its a good thing I just had lasagna for supper. I got tired of having steak fajita's, so I broke down and cooked something different tonight.

I was outside earlier and remembered to dig out a small clear plastic container I found in a car I bought last year. It had some electronic parts in it, most of which I can't identify apart from the resistors.

It wasn't until I thought about building a PI MD that I remembered I had them. Not sure how much of them I'd have a use for, or how much it might save me in cash. As it stands, if I were to order a pcb from Carl, it would cost me more for the international money order than it would for the board, so I might have to order a few to justify the cost and go into mini-mass production. Maybe I could sell one PI MD on eBay, or on here to recoup my costs?

F.

 

[Carl-NC]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

"As it stands, if I were to order a pcb from Carl, it would cost me more for the international money order than it would for the board..."

I also accept Paypal, personal check, gold... hell, I'll even take Canadian cash.

- Carl

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

"As it stands, if I were to order a pcb from Carl, it would cost me more for the international money order than it would for the board..."

I also accept Paypal, personal check, gold... hell, I'll even take Canadian cash.

- Carl

Here I was trying to talk myself into buying a few boards to justify the outlay. Now I have an offer to buy at par. (Little does he know how much hand holding its going to take to walk me through this project. )

I'm not sure what they'd do if they found me sending cash across the border, but I think I can work with the check thing. I'm just not into Paypal and I need the PI MD before I can get the gold.

I have heard that American banks usually charge as much as $5.00 U.S. to process a Canadian postal money order, (it was only made out for about $18.00), but I don't know if that money order was in U.S. dollars. I also heard, from someone that I had sent an International Postal money order, (in U.S. funds and issued by Canada Post), who said they had no problem cashing it at the U.S.P.S. office.

Just wouldn't want to send a $10.00 payment to have the banks steal half of it. So I'll try to make it to the post office here tomorrow, or Monday and check on my options. I just have to remember to check the GeoTech forum again for the mailing address. (Don't worry, I know the way there. )

F.

 

[Willy]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I sent an international money order to Texas a few days ago. It was drawn at my bank (Canada Trust) and is insured by Wells Fargo in the US of A. I've used these before and there hasn't been any problems at the other end. Canada Post also now has a system like Western Union where you can wire money.. without the usurious fees of Western Union. I've also sent money by that route. ..Willy.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

I sent an international money order to Texas a few days ago. It was drawn at my bank (Canada Trust) and is insured by Wells Fargo in the US of A. I've used these before and there hasn't been any problems at the other end. Canada Post also now has a system like Western Union where you can wire money.. without the usurious fees of Western Union. I've also sent money by that route. ..Willy.

Hey Willy!

I'm not sure about my bank here, I've never used them to send anything to the U.S., but I'll see what they have to say. It's not so much how much they would charge, as what happens when it gets to the receiver in the U.S. I know I've paid for items bought from people in the U.S. off of eBay, using the international money orders from Canada Post and they had no problem cashing them at the U.S.P.S. office.

I'd consider Paypal if they would only have a more secure arrangement with the banks, so that even if someone did get into my account, they would be limited in how much they could get. As it stands, even if I don't have enough cash in the account I give Paypal, the bank will take the money out of any other account I have until its all gone. Not like I'm anywhere near having too much cash, but I need what little I have.

I have to make some calls in the morning and I'll check on that while I'm at it.

F.

 

[99thpercentile]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

One the questions in the earlier posts was about using a palm pilot to log data. That is one of the biggest differences between metal detecting and geophysics, a digital record of the data tied to position. Check out the GEM-3 sensor from Geophex with the 30cm head for a metal detector that is actually a geophysical instrument. In that configuration the GEM-3 is designed for landmine detection. Using an HP iPAQ the software will show an image of the target when you find it based on a library of target signatures. The GEM-3 operates at ten user selected frequencies in the range of 100 Hz to 100 kHz. The problem with using a metal detector output to record the data is that the positioning of the sensor is very difficult to determine without very expensive positioning systems. Most users swing their sensors at least a little as they walk. This is one of the reasons that metal detectors are used for landmine detection, but the data is not recorded. In demonstrations of landmine metal detector performance there are huge variations between different operators wit the same instrument, even if the operators have similar amounts of experience.

I would like to see more software based metal detectors, but even for high end digital geophysical sensors there are still a lot of analog electronics involved.

 

[Functional]

Re: Whats happening with DIY Pulse Induction MD's? How about software based MD's

One the questions in the earlier posts was about using a palm pilot to log data. That is one of the biggest differences between metal detecting and geophysics, a digital record of the data tied to position. Check out the GEM-3 sensor from Geophex with the 30cm head for a metal detector that is actually a geophysical instrument. In that configuration the GEM-3 is designed for landmine detection. Using an HP iPAQ the software will show an image of the target when you find it based on a library of target signatures. The GEM-3 operates at ten user selected frequencies in the range of 100 Hz to 100 kHz. The problem with using a metal detector output to record the data is that the positioning of the sensor is very difficult to determine without very expensive positioning systems. Most users swing their sensors at least a little as they walk. This is one of the reasons that metal detectors are used for landmine detection, but the data is not recorded. In demonstrations of landmine metal detector performance there are huge variations between different operators wit the same instrument, even if the operators have similar amounts of experience.

I have an idea that could be applied even to MD's and in particular to Land Mine MD's and it doesn't involve the palm pilot, or any other brand of PDA.

I would like to see more software based metal detectors, but even for high end digital geophysical sensors there are still a lot of analog electronics involved.

I'm going to be posting to the GeoTech forums either today, or tomorrow with a proposal for an alternative device, (that is quite affordable and based on proven technology), to help in a variety of area's relating to: PI MD's in particular, GPR's and other similar devices. I'll try to remember to repost here with a link to the thread once I put it up. I just came up with the idea a few days ago and I'm still doing some web research, so I don't want to give out any unconfirmed details until I'm better prepared.

F.