I seek guidance: DIY metal detector

[MinnesotaStateUniversity]

HOW TO MAKE A METAL DETECTOR

Excellent tutorial. However it did not function in minnesota --too much iron in the grnd. I used it on wood chips at local parks. Was only good to about 6 inches, if that. Smallest bump and youd have to retune the coil. Very educational, but not so practical.

Heading to mexico in a month and id love to take one down to roam the beach. Most of the vlf schematics look pretty advanced for me. Anyone know of a good PI design? From the looks of it, bfo detectors are obsolete.

I seek coins and jewellery only

Im still roaming the arduino forum, but theres not much on here.

Thank you

 

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[gunsil]

Sadly the BFOs are obsolete. Not really too sad because the modern VLFs are so much better. I found tons of good stuff back in the early 70s with my Garrett BFO. I found most coins really weren't much more than 4-5" deep even if they were 150-200 years old if the ground hadn't been landscaped or graded. If you want to hunt beaches with any real efficiency you will need either a PI machine which has very little discrimination capability or a multi-frequency VLF if you want to hunt in the wet salt sand. They are expensive but necessary for this type of work. Single frequency VLFs work in the dry sand but even then it is better to have one with ground balance capability. I believe there are kits available for PI detectors but I have never heard of one for building a VLF.

 

[metal mania]

HOW TO MAKE A METAL DETECTOR

Excellent tutorial. However it did not function in minnesota --too much iron in the grnd. I used it on wood chips at local parks. Was only good to about 6 inches, if that. Smallest bump and youd have to retune the coil. Very educational, but not so practical.

Heading to mexico in a month and id love to take one down to roam the beach. Most of the vlf schematics look pretty advanced for me. Anyone know of a good PI design? From the looks of it, bfo detectors are obsolete.

I seek coins and jewellery only

Im still roaming the arduino forum, but theres not much on here.

Thank you

how advanced in terms of understanding the theory of metal detecting let me know and i can post links with permission of course best wishes

 

[Alan Applegate]

I'll stick my neck out a bit....

Assuming there is no mineralization in the soil, not a lot of trash, a basic BFO machine is just fine. In some cases, they're superior to any other detector. The issue should be obvious, but there are very few areas in the US that aren't mineralized.

There are several around that use one of the readily available PIC boards, but the real issue here is, the programming!

There is no doubt (or shouldn't be) that PI machines are the most difficult to design. If you have an understanding of how they work, you'll already know what that is so.

 

[woof!]

HOW TO MAKE A METAL DETECTOR

Excellent tutorial. However it did not function in minnesota --too much iron in the grnd. I used it on wood chips at local parks. Was only good to about 6 inches, if that. Smallest bump and youd have to retune the coil. Very educational, but not so practical.Thank you

Ingenious oscillator - mixer design, technically it's in the category of Pierce, but I've never seen it done that way before. At first glance it looks completely wrong and incapable of doing anything. Very clever.

When it comes to metal detectors, building one for fun is fine if you know what you're doing, but it's not a way to save money. If the objective is just to have a metal detector, buying one is the way to go.

--Dave J.