Help with SCL-007 fluxgate gradiometer kit

[bob]

Jan,


The dimensions are 4 inches by .25 inches by .082 inches (Mighty thin!) The material is #804. if you look on www.piezo-kinetics.com, you can see the specs.


600kHz was just a guestimate... You will need to figure out the frequency to be sure.


I was talking about IN STOCK parts. They will be more than happy to cut different sizes, but it will take time for them to make the ceramics.


At any rate, I will get a price for you!


Also, MSI is Material Systems Incorporated which is on the forum mainpage! To save everyone a click over to it, the URL is


http://www.matsysinc.com/


I wonder what their prices are like, and how big they go..


-Bob

[John Smith]

Re: relative range of detectors ?

>I agree that a Proton mag would be a good tool for what you are trying to do. Using a Dalton Proton mag (probably one of the most cumbersome) was used to find a German U boat off the coast of Texas in 17feet of sand. Texas isn't big on letting you salvage ship wrecks and they certainly wouldn't give permission to salvage this wreck. As you probably know be careful because some U boats used Mercury for ballast. The State of Texas wouldn't allow salvage for this reason. To me if its done right they should have allowed it. That ship is going to rust through someday and its all coming out.


Thanks Charles, this is all wonderful stuff for a newbie, you will all have to excuse my running around different subjects like a chicken with its head cut off, but after years of mundane electronic design, I have finally found a challenge that has got some real end product. ( Including some real "pieces of eight" promise - OK I play the lottery too :-)


The U-boats are more of a practice run, what I fancy are the 300+ shipwrecks around this Southernmost point of Africa.


see http://www.shipwreckexplorer.com/breakingnews.htm


A mag helped find the Brederode presumably due to the cannon and anchors.


>Also, some people believe that fluxgates aren't as sensitive as proton mags. That isn't true these days. Bob Marx happens to recommend a fluxgate in his book "Sunken Treasure-How to Find It". Of course, what does he know


I will try and find this book, what is the grin? is he a participant in this forum?


When it comes to sensitivity, of a mag for instance, I am getting a bit confused.


If the mag is measuring the earths magnetic field, and I build a pair of them, positioned several meters apart,( gradiometer) then I will be hoping to see the "distortion" or changes in the earths magnetic field caused by some magnetic object ( hopefully a montain of cannons and anchors ) that is nearer to one mag than the other.


At the point ( or pair of points) where the measurements are taken, the influence of the target on the earths magnetic field is completely independant of how sensative my mag(s) is/are, or even if I am present at all !


In other words, if the magnetic field at that point causes protons to precess at (say) 2300 Hz, then as long as my instrument is sensitive enough to measure that fields precession frequency ( OK the signal to noise ratio will affect the absolute reading, ) increasing the signal sensitivity seems a bit futile - or am I missing the point ?


By the way, I am at the point of winding the Fischer Price Proton Precession Magnetometer ( well actually a far east copy of the Fisher Price plastic rings ) and am contemplating sticking a couple of tubes in the plastic toroid so that I can compare ( say ) kerosene and distilled water as the medium, without having to rewind the whole thing.


Cheers


John

[John Smith]

Re: relative range of detectors ?

>I agree that a Proton mag would be a good tool for what you are trying to do. Using a Dalton Proton mag (probably one of the most cumbersome) was used to find a German U boat off the coast of Texas in 17feet of sand. Texas isn't big on letting you salvage ship wrecks and they certainly wouldn't give permission to salvage this wreck. As you probably know be careful because some U boats used Mercury for ballast. The State of Texas wouldn't allow salvage for this reason. To me if its done right they should have allowed it. That ship is going to rust through someday and its all coming out.


Thanks Charles, this is all wonderful stuff for a newbie, you will all have to excuse my running around different subjects like a chicken with its head cut off, but after years of mundane electronic design, I have finally found a challenge that has got some real end product. ( Including some real "pieces of eight" promise - OK I play the lottery too :-)


The U-boats are more of a practice run, what I fancy are the 300+ shipwrecks around this Southernmost point of Africa.


see http://www.shipwreckexplorer.com/breakingnews.htm


A mag helped find the Brederode presumably due to the cannon and anchors.


>Also, some people believe that fluxgates aren't as sensitive as proton mags. That isn't true these days. Bob Marx happens to recommend a fluxgate in his book "Sunken Treasure-How to Find It". Of course, what does he know


I will try and find this book, what is the grin? is he a participant in this forum?


When it comes to sensitivity, of a mag for instance, I am getting a bit confused.


If the mag is measuring the earths magnetic field, and I build a pair of them, positioned several meters apart,( gradiometer) then I will be hoping to see the "distortion" or changes in the earths magnetic field caused by some magnetic object ( hopefully a montain of cannons and anchors ) that is nearer to one mag than the other.


At the point ( or pair of points) where the measurements are taken, the influence of the target on the earths magnetic field is completely independant of how sensative my mag(s) is/are, or even if I am present at all !


In other words, if the magnetic field at that point causes protons to precess at (say) 2300 Hz, then as long as my instrument is sensitive enough to measure that fields precession frequency ( OK the signal to noise ratio will affect the absolute reading, ) increasing the signal sensitivity seems a bit futile - or am I missing the point ?


By the way, I am at the point of winding the Fischer Price Proton Precession Magnetometer ( well actually a far east copy of the Fisher Price plastic rings ) and am contemplating sticking a couple of tubes in the plastic toroid so that I can compare ( say ) kerosene and distilled water as the medium, without having to rewind the whole thing.


Cheers


John

[John Smith]

Re: relative range of detectors ?

>I agree that a Proton mag would be a good tool for what you are trying to do. Using a Dalton Proton mag (probably one of the most cumbersome) was used to find a German U boat off the coast of Texas in 17feet of sand. Texas isn't big on letting you salvage ship wrecks and they certainly wouldn't give permission to salvage this wreck. As you probably know be careful because some U boats used Mercury for ballast. The State of Texas wouldn't allow salvage for this reason. To me if its done right they should have allowed it. That ship is going to rust through someday and its all coming out.


Thanks Charles, this is all wonderful stuff for a newbie, you will all have to excuse my running around different subjects like a chicken with its head cut off, but after years of mundane electronic design, I have finally found a challenge that has got some real end product. ( Including some real "pieces of eight" promise - OK I play the lottery too :-)


The U-boats are more of a practice run, what I fancy are the 300+ shipwrecks around this Southernmost point of Africa.


see http://www.shipwreckexplorer.com/breakingnews.htm


A mag helped find the Brederode presumably due to the cannon and anchors.


>Also, some people believe that fluxgates aren't as sensitive as proton mags. That isn't true these days. Bob Marx happens to recommend a fluxgate in his book "Sunken Treasure-How to Find It". Of course, what does he know


I will try and find this book, what is the grin? is he a participant in this forum?


When it comes to sensitivity, of a mag for instance, I am getting a bit confused.


If the mag is measuring the earths magnetic field, and I build a pair of them, positioned several meters apart,( gradiometer) then I will be hoping to see the "distortion" or changes in the earths magnetic field caused by some magnetic object ( hopefully a montain of cannons and anchors ) that is nearer to one mag than the other.


At the point ( or pair of points) where the measurements are taken, the influence of the target on the earths magnetic field is completely independant of how sensative my mag(s) is/are, or even if I am present at all !


In other words, if the magnetic field at that point causes protons to precess at (say) 2300 Hz, then as long as my instrument is sensitive enough to measure that fields precession frequency ( OK the signal to noise ratio will affect the absolute reading, ) increasing the signal sensitivity seems a bit futile - or am I missing the point ?


By the way, I am at the point of winding the Fischer Price Proton Precession Magnetometer ( well actually a far east copy of the Fisher Price plastic rings ) and am contemplating sticking a couple of tubes in the plastic toroid so that I can compare ( say ) kerosene and distilled water as the medium, without having to rewind the whole thing.


Cheers


John

[mariusz]

Re: magnum - transistors

[mariusz]

Re: magnum - transistors

[mariusz]

Re: magnum - transistors

[Antonino]

Help with SCL-007 fluxgate gradiometer kit

It was a great experience to build the kit, as I am not an electronic expert. But I had a bad surprise when I tried it: the readings from the digital port are not stable: they steadily increase over time!

I changed the sensors, thinking they where faulty, but nothing changed.

Can someone help me? I use the SCL-007 in the high sensitivity mode (I want to detect underground archeological structures).

I have only a voltmeter to check the board.

Thank you very much.

[bryan]

Re: Help with SCL-007 fluxgate gradiometer kit

As I am about to field test my mag'. I would like to set it up for maximum senitivity and connect a computer to the digital output as you have.As I don't know how to do this, can you inform me of the right pin connections to try, and then I may be able to compare results with yours and come up with a solution

[Erich]

Re: Help with SCL-007 fluxgate gradiometer kit

Antonino,

Don't use the SCL-007 in the most sensitive mode......several people have tried, and it is nearly impossible to get it balanced.

Erich Kern

[Carl]

Re: Help with SCL-007 fluxgate gradiometer kit

I've never seen the output steadily increase with time. However, in high-gain mode, I've never had any success in getting the sensors balanced, and every slight movement of the mag makes the output go whacko. It's just too sensitive.

- Carl

[antonino]

Re: Help with SCL-007 fluxgate gradiometer kit

About computer connections, I had a very old Scorpion control computer (now
they have new models, see http://www.microrobotics.co.uk/) with digital
input ports and each of them they is able to read one bit, so I connected
each bit of SCL board digital input to 9 of these ports (and the ground of
SCL board must be connected too with that one of the computer). But my Scorpion
broke some months ago, so I made a connection with a LCD display board.

Bye
Antonino

[nickf]

Re: Help with SCL-007 fluxgate gradiometer kit

Hi,

You might want to get a copy of "Seeing Beneath the Soil" by Anthony Clark for archaeological specific surveying techniques and how to interpret the readings. Apparently the fluxgate mags used professionally like the FM36 use a square section aluminium tube only 50 cm long to hold the sensors to minimize the flexing of the tube because it's more practical to make the fluxgate sensors more sensitive than to use a longer and heavier tube. These mags usually go down to 0.1 nT or so and the Speake and co sensors aren't as sensitive as this so you can probably use something a bit longer. I've got a pair of the sensors sitting on my work bench awaiting use (once I finish my metal detector) - I was planning to try an aluminium beam a meter long to start with.

Nick

[Antonino]

Re: Help with SCL-007 fluxgate gradiometer kit

Thank you very much for the useful reference to the Anthony Clark book: I'have found it at Amazon.
Next month I'll try and get some discarded aluminium tubes from a friend of mine.

Merry Christmas and Happy New Year.

Bye
Antonino

[antonino]

Re: Help with SCL-007 fluxgate gradiometer kit

Antonino,
I tried posting this to the mag.forum address and it bounces back, so I'm sending
directly to you. If you will, please forward this to the mag forum.
Thanks,
Erich Kern

All,

The Speake FGM-3 sensors will not work inside metal tubing since it acts as a shorted
turn around the oscillator coil. Metal tubing either ferrous or non-ferrous will cause
the FGM-3 to either quit totally, or will greatly reduce its sensitivity. No permanent
harm is done to the FGM-3 sensor, it just won't work well inside a metal pipe.

Most ring core fluxgates (the torroid type) on the other hand will probably work
inside metal tubing, but again the sense coil, which is wound over the torroid will
see a shorted turn. Manufacturers who get big bucks for their stuff may have figured a
way around this problem, but consider, the Fat Quarters Software kit that Carl
Moreland designed goes for under $150.

BUT......aluminum 'L' channel slid inside a PVC pipe works fine. Always use schedule
40 PVC pipe, not the cheap thin wall PVC used for sprinkler branch piping. The larger
diameters are more rigid even though 3/4 inch is large enough, use 1 1/4 or 1 1/2 inch
PVC pipe.

Have a Merry Christmas and Happy New Year.

Regards,
Erich Kern