Suggestions on a DIY detector?

[Hephaestus]

Hey folks,

Looking to pick your knowledgable brains.

I'm looking to build a metal detector. Looking for it to be fairly versatile. Ideally using it to locate pockets of black sand / fine flour gold. But probably will do the occasional fun coin hunt too.

Where I'm differing from the norm - is I'd like for it to not be the typical analog beep unit... Constant Beeps/chirps etc drive me nuckin futz. I'd rather some lights / a display.

Wondering if you guys might be able to point me at a circuit that would make a good starting point? Planning to tie into probably a teensy microcontroller (main reasoning is the huge existing DSP libraries - seems like a great match given end desired result). And I like them better than Arduino (and the LC is 11$, may run it on a 3.2 for more power though if needed)

Ive tried following a bunch of the geotech builds only to find them abandoned, or suddenly incomplete schematics and selling boards/kits... And the Arduino builds seem very simplistic compared to the better detector options.

 

Amazon Forum Fav 👍

Diving for Pleasure and Treasure - Grab it through Amazon!

[signal_line]

What are you trying to do? Save money at the expense of poor performance? Somebody sells pulse induction boards/kits. Baracuda something or other.

 

[Ammoman]

I suggest getting an older detector and modifying it or possibly taking several detectors and combining them to make a frankintector.

 

[ecmjamsit]

There are some fairly recent model military mine detectors with an RS-232 interface. I think CEIA was the brand. One on ebay right now.

( link deleted by mod for rule violation, non-supporting vendor)

 

[signal_line]

Silverdog website has pulse kits like $50. "Inside The Metal Detector" has info/plans.

 

[Hephaestus]

What are you trying to do? Save money at the expense of poor performance? Somebody sells pulse induction boards/kits. Baracuda something or other.

I want to have my cake and eat it too.

Yes I know there's a hundred kits and designs based on kicking out a 12v waveform to a speaker. I don't want that. I don't expect you to understand what having a sensory issue is like, but a standard detector would give me a splitting headache in minutes (single digit).

So how does one define that - I want a decently sensitive piece of equipment. That I construct myself, and I want to be able to use a processor to handle frequency setting and which frequencies are used at what time and rather than using my brain and a circuit to interpret the data, I want to write code that handles the ground balancing, metal type etc.

If I choose I want to be able to throw on a accelerometer and GPS and save that data to to an SD card to be able to survey a creek and be able to look for changes over time (ie see what changes during a flood for example) have it stored as raw data, so one can process on a computer later - layering on the processing to identify elemental changes)

 

[Rick K]

Buy “Inside the Metal Detector” by G. Overton and C. Moreland. When you have read and digested everything in it, if you still want to design and build a detector, you will be much better prepared.

 

[Carl-NC]

Hephaestus, Geotech is exactly what you are looking for. It has gobs of starting points, and the stuff posted there is far from being "designed intentionally not to work." That's just silly. Sure, there are a lot of dead ends, largely because many of the denizens have grand ideas but not the skills to get it through to the end.

Building a decent metal detector ain't easy. Designing one is even harder. If it's something you really want to do, then asking questions on the best forum for that endeavor is probably a good place to start. I noticed that you only registered on Geotech 2 days before starting this thread, and you have yet to ask a single question. If you only spent 2 days looking at the projects there and left, then you're probably looking for something you're not gonna find, anywhere.

BTW, most induction detectors aren't going to locate flour gold. You can, under good conditions, locate black sand deposits with one, but an even better solution would be a magnetometer. And guess where you can find info & circuits for those?

- Carl

 

[Hephaestus]

Sorry if I come off harsh, but it's reality. I get it, I want to do something a bunch of people aren't as happy with. The response on those microcontroller threads at geotech - is not a lot different than here. I figured it might be a different crowd. Maybe slightly more interested in different options than ensuring circuits rule over a processor.

I get it, I like my old 1939 vintage am tube radio. Doesn't mean I refuse to install a satellite radio in my car.

So yeah, I asked here hoping that people here would be more interested in results than the technology and the specific circuits used.

Maybe I need to assess longer but I seriously doubt there's a point asking there.

 

[Carl-NC]

You can find lots of generic forums for micro development, but in a metal detector the micro is the easy part. The hard part is getting a good analog signal at the input of the ADC, and then knowing what the heck to do with it in code. All those generic micro forums won't have that expertise. Geotech is a good place for figuring out how to get a good analog signal, whether or not you end up digitizing it. You'll still be faced with figuring out what to do with the digitized signal, and a lot of that knowledge is unfortunately held closely by Big Metal Detector Companies. Short of getting a job at First Texas, Geotech is overwhelmingly your best bet for learning this.

A lot of people have gone to Geotech with the good intention of starting a collaborative effort to develop a micro-based design, only to have it stall. Once upon a time I even started the so-called "Commercial Design Group" for the purpose of developing a high-end PI design that could be licensed. Problem was, everyone wanted to do something different, and lots of people had ideas they didn't want to share. So I closed it down. Other efforts stalled because people grossly underestimated what was needed to get the job done.

Based on experience I can tell you that if you are a seasoned metal detector designer this project will take a year or 2. If this is your first detector but are decent at electronics design and micro programming, then bet on 3-5 years. That assumes what you're holding at the end is worth a darn for doing what you want it to do. If you're a newbie in electronics and programming, you probably don't have a prayer.

 

[signal_line]

You can find lots of generic forums for micro development, but in a metal detector the micro is the easy part. The hard part is getting a good analog signal at the input of the ADC, and then knowing what the heck to do with it in code. All those generic micro forums won't have that expertise. Geotech is a good place for figuring out how to get a good analog signal, whether or not you end up digitizing it. You'll still be faced with figuring out what to do with the digitized signal, and a lot of that knowledge is unfortunately held closely by Big Metal Detector Companies. Short of getting a job at First Texas, Geotech is overwhelmingly your best bet for learning this.

A lot of people have gone to Geotech with the good intention of starting a collaborative effort to develop a micro-based design, only to have it stall. Once upon a time I even started the so-called "Commercial Design Group" for the purpose of developing a high-end PI design that could be licensed. Problem was, everyone wanted to do something different, and lots of people had ideas they didn't want to share. So I closed it down. Other efforts stalled because people grossly underestimated what was needed to get the job done.

Based on experience I can tell you that if you are a seasoned metal detector designer this project will take a year or 2. If this is your first detector but are decent at electronics design and micro programming, then bet on 3-5 years. That assumes what you're holding at the end is worth a darn for doing what you want it to do. If you're a newbie in electronics and programming, you probably don't have a prayer.

Yeah I agree, but you left out the part about going insane. Maybe that's just for LRL's. So you are saying "Start washing dishes!"

 

[Carl-NC]

Carl - thanks for the input. It'll be a staged build, it's largely that front end I was hoping to just take a known functional entity as a starting point for the tx/rx circuits, build those then can start on the software side. I figured like many circuits there were known decent reference circuits to use as a starting point. Which is where I was going as well as looking for some input/debate on vlf/pi pl/freq/configurable thoughts for what I'm doing.

The Tesoro analog VLF is one of the most mature designs you can get. I posted the Bandido uMax many years ago, and the TGSL has been a very popular DIY project. It's a simple matter to digitize the demod signals and DSP them.

Yeah I agree, but you left out the part about going insane. Maybe that's just for LRL's. So you are saying "Start washing dishes!"

Mike, I'll expand my last estimate:

"If you're a newbie in electronics and programming, don't understand physics, and are trying to design something that defies science, you absolutely don't have a prayer."

He won’t listen - I have generally found that folks who pop up on a forum with a forum “handle” from mythology or some gaming nonsense are so wrapped up in their mind mists that mere information is of no use to them.

Oh I don't know about that, I think people just like to have fun with handles and avatars. When I started out on BBS forums, my handle was XYZZY which most graphics-gaming whippersnappers never had to type.

 

[signal_line]

Yeah Carl, I am fully aware. Pushing three years now on my Contraption LRL project.

 

[signal_line]

Hey Hepsy, ask Carl how his LRL project failed. If you catch my line of thinking, Carl is not an LRL enthusiast so you can't expect him to be passionate about it. That passion is kinda the magic/essential ingredient.

"Any kind of love without passion ain't no kind of love at all."

 

[Treasure_Hunter]

End the insults or lose the right to post.

Thread is locked for now.

 

[Treasure_Hunter]

Thread has been cleaned and restored. POST BY OUR RULES, this includes no insulting or talking down to other members.

 

[Treasure_Hunter]

Signal_line, don't start it back up. Please move on.