Stop building PI detectors!

[rickb]

Funfinder said:

It's clear that you will not stop here with the PI stuff but perhaps you should
use some little satellite dish for better radar wave reflection!

You really need to stop posting nonsense on a technical forum. PI detectors do NOT use the principles of RADAR to detect targets. How many times must this be said?

You may be confused by the article link posted on Geotech. http://electronics.howstuffworks.com...-detector4.htm It wrongly uses terminology related to radar to explain how it works.

Read this article for the real story
http://www.nuggetshooter.com/article...Idetector.html

[kt315]

Dave Johnston is crying and digging his famous IMPULSE in the ground kneeling. LOL!

http://fisherlab.com/hobby/davejohns...rinterview.htm

DS: Would you mind giving us a list of detectors you’ve had a hand in developing?
Dave: "Old Fisher: 1260, 1220, 1210, 1225, 1235, 1265, 1266, 1280, Impulse, CZ6, CZ5, CZ20, Gold Bug, Gold Bug II, TW6/Gemini, FX-3, and several industrial products.
Tesoro: Diablo MicroMax, Lobo Supertraq.
White’s: DFX, Beachhunter ID, GMT, MXT
Troy: Shadow X5
Bounty Hunter & related products: nearly everything we manufacture. Many of these products are adapted from the original Teknetics which was designed by George Payne. The Teknetics T2 however was an entirely new design.
New Fisher: F75, F4, and everything else since then.
On most of the above I was the lead engineer. On the White’s DFX and Beachhunter ID I developed the multiple frequency circuitry, and other engineers designed products around that circuitry. In addition to the above there are many products on the market which are adaptations by other engineers of products I designed."

Dave: "About 1985 I built a real sweetheart of a discriminating PI unit, not very hot in air test, but it was simple, lightweight, powered by one 9 volt “transistor battery”, ran quiet in bad ground, had no bad habits, and you didn’t have to dig any trash. It morphed into a fully static TID machine which Fisher came close to releasing about 1989, but its reliance on fully static operation which was supposed to be an advantage, was in fact a fatal flaw for a TID machine. Stripped back down, it became the Impulse which was strictly all-metals.
Industry insiders know about a PI TID machine which a fairly sharp freelancer has had under development for about 5 years and which is said to be nearing production. Whether or not that one makes it, I expect there will eventually be others.
The next great advancement in metal detector technology will be….. ahem… we’ll all know when whatever it is actually hits the market and customers say it’s a great advancement. I hope that when that event happens, it’s got our trademark on it. If it’s got someone else’s trademark, I guess we’ll just have to play leapfrog."

[ionut_mtb]

In my opinion PI machine is good on the beach(wet sand, salt water does not affect function and depth) , but you have to dig everything, every single bit of metal, ferrous or non ferrous, because using a small delay for small gold/silver automatic you will dig small non ferrous targets also . In land, is to much trash, but like kt315 user showed us is good for hunting big relics, or hoards, with big coil which does not feel the nails and other small junk (or not), is seeing thru it!

[dfbowers]

Yea, but I paid for my inexpensive homebrew PI at the beach a few times over.. and then some with finding platinum. Plus. I know exactly how it works.

[SVEN1]

Yea, but I paid for my inexpensive homebrew PI at the beach a few times over.. and then some with finding platinum. Plus. I know exactly how it works.

Me too..LOL

I have a blast using my PI even in trashy areas. So I keep building. I dig about as much garbage-trash items with my PI as with a VLF.

Just a sampling of clad not showing the many many $1 and $2 coins I found and spent. Found just as many pennies as the clad pictured. As well as gold rings.



And this is a cross found with one of my water version PI's owner.

[ionut_mtb]

Can you compare both pi and vlf detectors? Only people who used both for saltwater wet beach and underwater ? What isyour oppinion about xp deus in these circumstances compared to PI. Are u using only vco? I have a surf pi pro but never used in the beach because is forbiden in my country. It goes to 5us very sensible to small metal. Now i ve moved to sweden and want to try. For pi every signal is almost same. I mean can be small gold(foil) close to surface and have good signal or same signal for deep can big iron... so you dig everything. is not like that?

[jladre]

I mean can be small gold(foil) close to surface and have good signal or same signal for deep can big iron... so you dig everything. is not like that?

Are you sure about that? I have a pi which can distinguish iron and conductive target which i used for beach and underwater hunting.. i have also a vlf machine which super for wet sand hunting, if i compare the two in beach hunting then nothing have advantage to other in vlf to insure to hit all good targets you need to only discriminate iron in order to find gold copper and silver, while my pi i can set it to ignore iron target so all conductive target are being hit.,about the depth my minelab quattro vlf machine can hit 12-18" depth coin target while my pi can hit it at around 16".. im using felezjoo pi, baracuda pi and a quattro vlf..

[WM6]

Let see what experts (R.Lagal & C. Garrett) say long ago (in year 1979 !!!):

[Funfinder]

Sure, some easy selfbuilt PI is 100x better than no detector.
And it does a good job if you search slowly and without discrimination.
Profis dig alot iron anyway because otherwise they could miss important finds.

This is also important because very deep finds no longer have good metal-ID-values
and might show up for the detector as iron anyway, even if they are noble!
Remember: Searching without discrimination = Searching with maximum sensitivity!

But time is money and discrimination makes the search much more aim-orientated!
And its a huge difference if someone can sweeps his coil at a speed of
2meters within 0,2seconds by still maximum depth or if this needs 1 second -
5x longer, because the PI needs this time for not losing any sensitivity or depth.

Besides the PI doesn't finds cavities, mineralized stones and special meteorites
and has a much higher power-drain which leads to heavier and therefore more
unpractical detectors, especially if it comes to 50cm coils!
Take a look how heavy those expensive Minelabs are ...

And walking inside some 1 m coil while holding in the middle the electronic-unit
also is just some amateur-solution, because the PI of course detects this, too.

Another question would be how stable and sensitive is the PI at areas with
strong electro-smog-fields or near high-volage-lines.
I doubt that the neverending on-off field from the PI contributes to stability
under such conditions! And there's no way of "reading between the lines" as
it is possible with many "snap-crackle-&-pop"-signals creating VLF detectors.

The output signals of many PIs are totally annoying anyway - like some
on-off going siren or a howling wolf !


However:
We live meanwhile in a world of LED- or LCD-displays plus micro-controllers
and soon will be all kind of parts available to homebrew modern induction-
balance detectors incl. all features with the same expenditure as those still
here so popular PI-kits or DIY-projects.

And last but not least also the market itself speaks a clear language:
The most people don't wanna buy PI-detectors, for many good reasons ...

[Teleno]

I doubt that the neverending on-off field from the PI contributes to stability
under such conditions! And there's no way of "reading between the lines" as
it is possible with many "snap-crackle-&-pop"-signals creating VLF detectors.

The output signals of many PIs are totally annoying anyway - like some
on-off going siren or a howling wolf !

Why do you write about PI when it's so obvious you've never used PI?

You're a waste of time for everyone.

[Carl-NC]

Funfinder,

A PI detector is absolutely wonderful for some kinds of hunting, and will beat a VLF or MF detector hands-down. It is absolutely miserable for other kinds of hunting, where a VLF or MF works better.

I think your real argument here is not to stop looking at PI (it has a long way to go), but to do more with VLF & MF. It is true, not too many people on Geotech tackle VLF/MF projects, because they are so much more difficult than PI.

--Carl

[rickb]

Carl: His real problem is that he thinks PI detectors are based on the principles of radar, and are therefore a waste of time.

[ionut_mtb]

i know there's a lot of projects and schematics here. due to lack of time i want to buy a kit (pcb and components) for a Pulse Induction md, strictly for underwater/beach/wet sand. no display, no programing(hate it although is good). only kit i saw is silverdog Baracuda and Minipulse. thanks

[kt315]

Funfinder,

A PI detector is absolutely wonderful for some kinds of hunting, and will beat a VLF or MF detector hands-down. It is absolutely miserable for other kinds of hunting, where a VLF or MF works better.

I think your real argument here is not to stop looking at PI (it has a long way to go), but to do more with VLF & MF. It is true, not too many people on Geotech tackle VLF/MF projects, because they are so much more difficult than PI.

--Carl

i guess FF do not know that russian one had released PI-VLF-all-in-one detector two years ago. hybrid? i do not know, this named 'universal'.
its frequencies range --- 4-12kHz (IB), 400Hz (PI)

http://www.metdet.ru/universal.htm

[SVEN1]

I do offer Mirage PCB and component parts kit, have made about 10 u/w units over the past few years. Guys love them for saltwater beach and surf hunting.




Just had a new batch of PCB's made. PM me if you want pricing and more info.

But, you can also make a water PI from the Barracuda, Mini-pulse, Surfmaster etc.