Motion detector circuits

[Peter Jones]

Hello all , I'm new to this site and think it's great , I'll have to spend some time reading previous posts .

Now to the point , are there any diagrams of "motion" type metal detectors , either manufacturer's obsolete ones or amateur designs , available on the web?

Saxon had a link to one described as "coming soon" , but this link disappeared after i sent an e-mail asking when it would be available.

Thanks in anticipation ,
Peter.

[BG]

Re: Motion detector circuits

Peter:

Your question is basically similar to mine (below). Commercial detectors using motion discrimination are usually induction balance designs.

I've searched high and low for a reasonably simple design that had adequate depth and some sort of discrimination. The closest I've found is here:

http://members.aol.com/omlcgm/radiometer/radiometer.htm

I've been looking for some older Tesoro circuits, since they seem fairly basic yet powerful detectors (no DSP/microprocessors on many designs) but haven't had any luck. This link is for somebody claiming to have some, but he won't respond to my emails... perhaps you'll have better luck:

http://www.geocities.com/vlfdetectors/

Also, take a look at the Magnum. It's quite complicated, but it may be the closest thing to what you're looking for.

Hope this helps
BG

[Peter Jones]

Re: Motion detector circuits

Thanks for the reply , I have the details of the Radiometer Ferret printed out , and also the Magnum , and I will be experimenting when time allows.
I own a commercially made motion detector (entry-level) that is now superceded by the manufacturer , I may reverse-engineer that or ask the company if they are willing to sell me a diagram , as it is now obsolete to them commercially.
I agree that a Tesoro design would be a very capable detector , perhaps this is why diagrams are difficult to obtain , however I think manufacturers should release designs of obsolete models , as even if a competitor got hold of it , it would be like someone selling old Cortinas in competition with Mondeos (for want of a better analogy)

Thanks , Peter.

[Sean Goddard]

Re: Motion detector circuits

I have the circuit diagram of the Tesoro Silver Sabre 2. I'll post it on here this weekend.

You'd be surprised just how much alike most of this manufacturers circuits are.

Well, I suppose if they're tried and tested, why change them?

[Peter Jones]

Re: Motion detector circuits

Thanks , i'll look forward to seeing it , I reckon if Tesoro use similar circuitry in much of their range , comparison will show the effect of the changes.
I intend to experiment with circuits on breadboard to better understand how they work and (if possible) any improvements that can be made.
It is encouraging that many great detectors currently made are not microprocessor controlled and have relatively simple circuitry. there is hope yet for the tinkerers of the world!

[Sean Goddard]

Re: Motion detector circuits

Trust me Peter, even the most "complex" of microprocessor controlled detector is still primitive, compared to the stuff I used to work on.

There seems to be a tendency for manufacturers to say" Hey, we've found something REALLY cool, and it's NEW". Not so. Most of the micro's these guys are using are out of the "Ark", and are all but obsolete, and VERY low power processing wise.

What the detector world needs is someone who has worked with this stuff "from birth", not a bunch who, in the main, have no real concept of what's REALLY possible.

When someone realises what can actually be done by applying REAL processing power to detectors, then the whole industry will be turned on it's head, and you'll start to see machines appearing with INCREDIBLE discrimination, and depths.

Most people will tell you that there are noise, and ground signal problems, but they do not have a REAL appreciation of what is possible using raw POWER processing. I've seen a radar target pulled out of a signal that was visible only as noise!

When SOMEONE with a military radar background designs a detector one day, then you'll see a lot of the other companies disappear. They just won't be able to compete.

That day is coming, and sooner than most manufacturers would like to see.

[Dave J.]

The upcoming beeper revolution

Thanks, Sean. If I merely agreed with you, that wouldn't be much fun for either of us, so I'll offer some contrarian viewpoints.

1. If company management is unable to achieve a vision of what's possible, company management won't pay an engineer to do it. Part of the problem is being able to communicate that vision. Since managers tend to be conservative and fearful of change, showing them a picture of what could be different usually doesn't register with them.

If the top guy does "get it", then there is this corps of underlings who are afraid of change, and their resistance can, in the end, cause a CEO to throw in the towel.

Usually the only way for a company to make major change, is to see a competitor do something first, or to get a new CEO whose mind doesn't have a past history on which to remain fixated.

2. THIS IS A SERMON (not aimed at you, Sean!)

Business, like any other evolutionary activity, goes through times of stability punctuated by revolutions. The last major revolution in the metal detector industry was during the late 70's thru early 80's, when "motion VLF" became the mainstream technology. There has been steady progress since that time, but many good products nowadays are based on 20-25 year old platforms.

In the meantime, the world has not stopped. Revolutions happen because the energy to drive them has built up against restraints. In the metal detector industry, the "energy" consists of new and improved technology and new approaches to engineering and its management. The restraint is management's general fear of doing things that don't fit with the old comfortable ways of doing things which seem on the surface to have been successful so far. Minelab has, to some extent, been an exception to this.

Because revolutions happen under conditions of release of pressure, once they start, they go very quickly, with unpredictable results. Thus, revolutions favor those who understand this nature of revolutions and embrace the speed and uncertainty with characterize them. Embracing revolution means MAKING CHANGE ITSELF THE CORE OF THE BUSINESS PLAN, by which competitors who stand still get wiped out, flattened down a bit, or absorbed. When revolution is going to happen no matter what one's business plan, then embracing revolution and using revolution as a creative tool for competition is the most rational business plan possible.

END OF SERMON; NOW SALESPITCH: Is there a manufacturer out there who realizes the competitive advantage of deliberate revolution, and would like to hire an engineer who has been laying the groundwork for years, anticipating this revolution? If so, please contact me.


OK, BACK TO REPLYING TO SEAN'S POST.....

3. Sheer processing horsepower, used intelligently, doesn't make good analog/searchcoil designs unnecessary.

4. It's one thing to have processing horsepower, it's another thing to know what to do with that horsepower. Many of the problems of beepering are unique to beepering, and require custom algorithms to deal with them effectively and efficiently. (I expect a lot of flak on this statement, but that's fine with me.)

--Dave J.

[Sean Goddard]

Re: The upcoming beeper revolution

How eloquenlty put Dave. I agree with you 100%.

Funny really, I feel the same way about this industry.

I agree that raw horsepower is NO substitute for good design.

I have done a LOT of research into this subject, but I also realise that there are a few VERY CLEVER people out there in the beeper industry who will put me in the shade, and I suspect that most of them frequent this forum.

There is still a lot I have to learn, but with forums such as this, the knowledge that is being disseminated is helping us all.

If I could hire you as an engineer, then I would, but I think you know how difficult it is to raise the finance for anything new or "revolutionary".

Maybe we should collaborate via personal emails on a new machine, then we'd BOTH reap the benefits, and so would the rest of the beeper industry.

Let me know what you think, I'd be prepared to disclose some ideas to let you evaluate just how far I've got.

[Dave J.]

beeper revolution further comments

Sean, although I've published some of my ideas on several forums, there are certain critical pieces of technical IP which I'm hanging onto, at least for now. It's probable that some other engineers know some of this same stuff; and of course there are things that some other engineers know that I don't.

There is technical knowledge kicking around, in abundance. Here's what there's a shortage of:

1. Management which has a clear vision of what is possible and how to achieve it.

2. Engineers who have a broad enough grasp of beeper engineering (a grasp that extends into things like advertising psychology and geophysics) to formulate a superior product description.

3. Engineers who understand the "devil in the details" well enough to translate what's theoretically possible into engineering excellence.

4. Companies driven by a sense of mission, rather than a culture of political turf protection.

****************

A few days ago, I wrote letters to the stockholders in a metal detector company who I figured there's a chance might hire me, in which I explained that the current crop of top-of-the-line metal detectors are sitting ducks waiting to be knocked over by the next wave of competent product engineering. I pointed to a variety of lines of evidence how this could happen.

The funny thing is, is that if every beeper company on the planet waits for a competitor to make that wave first, then nobody will make that wave. Ten years from now you could still have the same companies building pretty much the same stuff! This would be unthinkable in any realm of consumer electronics other than the beeper industry.

Now, some facts about the real world that many engineers, including myself, frequently forget.

1. The prevailing human condition is ignorance and incompetency. Companies survive primarily because their competitors are equally ignorant and incompetent. For instance, in the beeper industry, it is easy to point out Minelab's willingness to innovate technology as a core competency, but there are other major areas where they are clueless and seem destined to remain so.

2. We would like to think that businesses are run for profit; or, better yet, for social good made possible by profit. And, these things do happen to some extent in most companies. But in general, businesses are run from top to bottom for personal reasons mostly having to do with ego and personal power. Businesses survive despite their lack of general concern for profit, because their competitors are similarly lacking in a vision capable of producing a sense of mission which will subordinate ego to the common good.

Once in a while, vision and mission happen, organizing and directing human effort, and erasing the scattering of energy produced by individual selfishness. That is how revolutions happen, and how companies come out of stagnation or out of nowhere, and suddenly transform an industry.

That means change-- the thing most CEO's fear most, but eventually they get it anyway. The undertaker guarantees it if no one else does.

Engineers worry about it too. Suppose that for whatever reason-- legislation, social change, failure of the entire beeper industry to embrace a philosophy of competitiveness, whatever-- the beeper industry were to slide into oblivion. With nobody buying better beepers, what I know about better beepers becomes worthless. You too, Sean.

Sean, about 3 months after I went to work for Fisher back in 1981, I wrote a memo predicting than within about 5 years, single-frequency metal detectors would be obsoleted by multiple frequency units. (At that time I didn't know about pulse induction, but that's not my point here.) Two years later, in 1983, I built and field tested a prototype that got rid of iron targets in highly mineralized ground. It was sorely deficient in other respects, but that it did well. Here we are nearly 20 years later, only two American companies doing multifrequency, both of them using front end technology I developed for them, and (as far as I know, based on their advertising) neither company uses multiple frequency methods for iron discrimination.

In the case of Fisher, if they don't have anything else, they have my early work on file. In the case of White's, their own patents show how! Words can hardly express my frustration and amazement at how slowly American beeper companies put onto the market technology they already know about.

But, y'know, there are other realms of human endeavor which take place on time scales measured in thousands and tens of thousands of years, so perhaps the flash-in-the-pan of beeperdom isn't so reactionary as we customarily suppose.

Sorry if this post is more pessimistic than most. Attitude will probably improve when I get work sufficiently remunerative to continue living indoors.

--Dave J.

[Frank Wallis]

Re: beeper revolution further comments

Hi Dave
I can not agree with you more in regards to management,a very good example of your point was Xerox,and the computer.
Here in Australia we were very frustrated at the detectors that we had and there inability to handle mineralization.From time to time we heard rumores that a P.I was being developed by some one in South Australia,then when it arrived,and I tried one I told my friends to rush out and buy one,and throw you other ones away.But that is history now,and any one that hunts for gold will tell you that they beleive that there is still gold in the ground,but we cannot hear it with this generation of detectors.
There is certain nuggets that have a higher percentage of of other metals in them which will not register with the machine.I have one nugget which weighs 20 grams and is flat,and will not register past 12 inches.
Regards
Frank Wallis

[Ed in SD]

a market segment not mentioned

Sure, the beeper industry seems to us to be centered on the hobbyist level. A more lucrative area would be the military mine detectors and airport screening applications. Utility companies need it too for locating pipes and cables.

The early designs were driven to the VLF stage by the military. With a few refinements, that's about where we are today.

Explosive landmines are getting way too "techy" and becoming harder to detect with the conventional designs. It seems such a shame that people will put their minds to destroying another human more effectively, but it only accentuates the need to have some brains working on the opposing side.

I did a pretty thorough search on the web awhile ago for metal detector schematics, circuits and similar keywords. It was surprising how many times the mine hunting application came up. There is a real human need for a relatively simple circuit that is easy for an untrained volunteer to operate that can locate the new mines which contain little detectable metal. And a worldwide market exists for it. Do a search, you might be talking to the wrong "management"!

On the "homefront", I expect the guy who comes up with the detector that works like a fish finder, with an actual image of the things being detected, then that person will be the new king of the heap!

As for the hobby machine manufacturers of today, they might be thought of as the American car manufacturers of the 70's. They didn't get shook up till the Japanese imports stole the entire market. Prior to that it was all sliding downhill, and we made some very pathetic cars in that era.

Just my two zincs worth!
HH-Ed

[Sean Goddard]

Re: beeper revolution further comments

What machine are you using Frank?

[Al]

Re: Motion detector circuits

Did you post the Tesoro Silver Sabre 2?

[Dave J.]

demining, and another American lunch eaten by Minelab.

There are two basic problems in mine detection: being able to find the mines, and being able to ignore the stuff that isn't mines. Metal detectors are moderately good at the former, and can be quite a bit better, but that only makes the other problem worse.

Most battlefields are littered with metal debris, and many areas that aren't battlefields have a lot of metal debris left over from other human activities. Most experts have come to the conclusion that what's needed is not a better metal detector, but something that will obsolete metal detectors as we normally think of them. A number of technologies are being looked at, from underground radar to chemical sniffing technology, and systems which combine several technologies including metal detection. At least one company is working on ultra broadband metal detection.

Thus, mine detection is parting ways with the kind of technology used in consumer metal detectors, and most metal detector companies don't have the technical expertise or funding to pursue new mine detection technology seriously. Minelab may be an exception.

The "fish finder" is what everybody wants in a consumer metal detector, and nobody knows how to do it, so we have a variety of compromises, mostly based on either icons or graphs.

The funniest compromise is the Minelab Explorer, which is designed to literally look like a fish finder. The part that isn't funny about this, is that it shows that Minelab has decided to take industrial design seriously. If you take a look at American metal detectors looking for visual evidence that they even know such an engineering art discipline exists, I believe you'll come up empty-handed. Even less funny is that at least two companies do know, because I've explained it to them.

It would be nice to see an American company get tired of having Minelab eat their lunch, and decide to compete. And, since I'm presently unemployed, it would be nice to be hired by a company who intended to do just that.

-the guy in Prescott

[Frank Wallis]

Re: beeper revolution further comments

Hi Sean
I have two,2000 modified and 2200d.

Regards Frank