Jump to content

Recommended Posts

The best source I've found for what's going on inside a metal detector is of course,

"Inside the Metal Detector" by George Overton and Carl Moreland, Geotech Press, Sweet Home Oregon, 2012

 

Comes complete with theory and actual MD designs that have been tested.

Among the designs, BFO, off-resonance, T-R, IB, and 5 PI designs.

Covers the pseudo-science of long-range detectors and exposes the guts inside several.

And not to be forgotten, coil design and actual builds.

 

The book ain't exactly cheap, but the only technical manuals I've found that weren't weren't really technical unless they were used books. When I read the previous sentence back, I thought someone sneaked a handful of marbles into my mouth.

 

eric

Share this post


Link to post
Share on other sites

A Trash-80 and a Commodore VIC-20. Used both, but never bought one.

Yah, those were the good old days ... Not really.

I started on a IIe at the Ft Richardson Library and finally bought a turbo XT clone. Which I still have.

 

You really don't need a microcontroller for a T-R.

2 transistors can generate the radio signal with the audio riding on top.

The PICs from Microchip are great little MCUs, but the Arduino is getting a large following.

But I still have several 16C54 and 16F84 PICs on the shelf.

Have to admit I'm still fond of BASIC.

 

Where MCUs really shine is for PI detectors.

You can change the pulse repetition rate, pulse duration and sample delay with good software and do your selecting with a switch.

 

Much of the programming needed can be cut and pasted from programs posted on the web.

A great resource for programming of MDs can be found on the Geotech forums.

For PI, look to Eric Foster on the findmall site as well as the Geotech site.

 

And yes, older books have far more meat and less fluff.

My college chemistry manual was written by Linus Pauling and his brother.

Some of the content would horrify many in today's liberal academia.

Although a little shy on circuits, "The Metal Detector Handbook" by LeGaye and the "Official Handbook of Metal Detectors" by Kortejarvi really get into the physics of metal detection. Good stuff that you won't learn in college.

 

Let me return you all now to the regularly scheduled programming.

eric

Share this post


Link to post
Share on other sites

If you really want to know what's going on inside a metal detector get a degree in Electronics like I did and work in the industry , very complex food service metal detectors and expensive , even with a Degree and training plus practical experience you will still need  a service manual and be able to read the schematic and understand what all of the components are and there function , this is not a simple task because a little bit of knowledge can be very dangerous just like in scuba diving ! :)

Share this post


Link to post
Share on other sites

If you really want to know what's going on inside a metal detector get a degree in Electronics like I did and work in the industry , very complex food service metal detectors and expensive , even with a Degree and training plus practical experience you will still need  a service manual and be able to read the schematic and understand what all of the components are and there function , this is not a simple task because a little bit of knowledge can be very dangerous just like in scuba diving ! :)

No. It isn't dangerous for the most part and definitely not at the voltages found in metal detectors used in the field.

Obtaining a college degree in electronics contributes absolutely nothing to the science, design and use of metal detectors.

As a matter of fact, college tends to be a very poor source for any education in RF design. And especially in the case of PI detectors, transformer design.

 

There is a world of difference between stationary MDs for food safety and MDs designed to be portable and fully capable of discriminating in an environment where ground hysteresis is variable.

 

As dangerous as scuba diving?

Yah, there I was. Just after soldering that 2N3906 transistor in backwards, I put the power to it.

It was horrible.

I had to dig out the solder snuffer and reheat the soldering iron.

Another 2¢ transistor trashed.

But not even a glimpse of smoke.

 

eric NL7ZW

Share this post


Link to post
Share on other sites

Every detector has its own design characteristics and learning more about various functions, settings, adjustments, etc. to get the most out of a detector is very much a detector specific effort. 

Operator's manuals cover much, but sometimes there are undocumented features which the operator finds by using the detector.

Share this post


Link to post
Share on other sites

One of the good things about trying to learn more before you make a purchase is that most detector makers now have the operator manuals for all their detectors on line.

(useful also in case you lose one)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×