Who here has built a metal detctor (even from a kit)?

[bigticket]

We want to hear your story.

 

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[Michigan Badger]

Re: Who here has built a metal detctor?

I built a Heathkit unit back in the 60's? and it stunk.

I also have a homemade BFO transistor metal detectors made ca. 1960. It's made out of wood and I found it on ebay one day. Haven't even tried it to see if the darn thing works.

But I know what you mean, no, I haven't personally designed a detector.

 

[bigticket]

Re: Who here has built a metal detctor?

Even if someone built a kit, that is still building a detector.

 

[goldfinder]

I have. I tried VLF and 2-box but couldn't get much results out of them. I suspect the circuit design was bad on these. I built several PI machines. I had the best luck with the Gary PI detector (Chemlec website).

It will detect a 1 oz gold coin at 3 feet. Currently building a PIC PI machine with at least as good capability.
A PIC uC controls the front end coil xmit and collection time. Another PIC does signal processing on the output.

[email protected]

 

[bigticket]

I have seen that site. That guy is really something!
What have you found with the detectors you have built?

 

[Michigan Badger]

I have. I tried VLF and 2-box but couldn't get much results out of them. I suspect the circuit design was bad on these.? I built several PI machines. I had the best luck with the Gary PI detector (Chemlec website).

It will detect a 1 oz gold coin at 3 feet. Currently building a PIC PI machine with at least as good capability.
A PIC uC controls the front end coil xmit and collection time. Another PIC does signal processing on the output.

[email protected]

At last, somebody to talk PI. Man it's hard to find any info on PI's !

Please come back and tell all.

In addition to the above question: How do we find this website? Cost to make a PI? Does it require technical knowledge to build one?

 

[bigticket]

http://www3.telus.net/chemelec/

 

[Michigan Badger]

Anybody ever try this unit?

http://www.igkelectronics.com/metal_detector_PI701_KIT.html

 

[mgdigger]

I built a kit once back in high school electronics class (68). It could find a refrigerator at 6 inches.

 

[jeff of pa]

Back in the 60's I bought a RELCO Detector.
It had to be Built, & the operating tone, came over a Small A.M. Radio
that I had to Supply Myself.

It Operated on B.F.O. Principals.

(Beat Frequincy Oscilator) I think was what B.F.O. stands for.

ALL METAL, No Rise in tone, The tone was Distorted, when ran over Metal, and IRON ORE
(Which My area is Loaded With).

Needless to say, It was only good for Large Relics, Heavy, and something I wish I could Forget

 

[bigticket]

You could have just built a simple oscillator, and used that with a radio.

 

[jeff of pa]

You could have just built a simple oscillator, and used that with a radio.

? Yea , But I was about 13 or 14 at the time.

? ? ?I had to take the Kit to a Neighbor who Knew how to Solder, Just To Get the Tuner Built.

? ? ? ?I was able to Wind the Coil Myself. But Knew Very Little About Electronics.

 

[U.K. Brian]

Many of the P.I. designs are hard to construct though Goldpic with their Goldpic 3 provide a circuit board and micro controller with embedded software for around $40 (+postage, their in South Africa) to make things easier.
I've just bought a (I assume) non working meter discriminator for a little over $2 off E-Bay. The Altek Shadow VLF meter discriminator which was a kit that came with a ready built coil back in the 80's. I tried one at the time and it offered similar excellent 'in iron' performance to the Compass 77b but with more depth. Luckily the plans are still on line and I've just treated myself to a new soldering iron.

 

[bigticket]

Just remember that the goldpic kit does not come with the minor parts (capacitors, transistors, etc.).

 

[U.K. Brian]

My $2 Altek arrived and worked...3" on a quarter. Few hours on and everything works except a tone switch which wasn't in the original plans. Air test (with small iron discrim.) is now up to 9 inches. Its a quad mode VLF/TR. Ferrous/non-ferrous meter, six knobs, some multifunction, three pushbuttons and the mystery tone switch. Claimed in ground depth was 'in excess of 12 inches on a single coin'. We shall see.

 

[davidtn]

The Heathkit I "built" (OK - soldered) back in the 70's is the reason I came back to detecting last year.? I have fond memories of it.? I found a bunch of wheaties with it although I must admit they were probably no more than 2 inches deep!

 

[Ed in SoDak]

Geotech has a PI design with a lot of supporting links and pages. They talk some tech stuff in the forums.

I collected a lot of schematics and designs off the net. After a few false starts with some very basic circuits, I got a simple BFO using op-amps to work on a breadboard, so I moved it to perfboard and housed it in a small metal tin. Because of the wiring being much shorter and arranged differently, I had to rework a few things to get it going again in the case.

Instead of the 4" coil, I modified a TV choke to work as a pinpointer coil. The detector works alright, but tends to drift and the tone begins to slowly riseeeeeeee!! It's also pretty quiet in the volume department and hard to hear at busy areas.

If I were to do another, I'd rather build something along the lines of the Falcon pinpointer. I've built a lot of kit hi-fi and test equipment, but this was the first circuit I'd built from raw parts and got it to work. It wasn't my circuit, but I came up with the parts layout and case design.

-Ed

 

[bigticket]

What is the link?

 

[bigticket]

I meant the link for the detector that he built.

 

[Huizer]

I have built the proscan PI from the geotech web site. Has a great forum for help and I got the thing to work with a few modifications. ( the original schematic was drawn by a Polish dude) anyways, some of the parts were harder to find so I found what came close and substituted away! It was a nasty looking thing cause I built it on a test board and had wires everywhere and you could only hold it here or there because if you didn't it would squeal. It was cool though....you just set the threshold tick nice and low and steady and when you found metal the ticks would speed up into a tone. Found some old toy cars in the backyard where the sand box used to be. Had to do it right when I got home from work before my dad got home or he would give me greif. That was about 6 years ago.

Dan.