IGSL

[simonbaker]

Pot Direction
I still don't know from the schematic which adjustment is Disc1 or Disc2, but that cannot be too difficult to sort out!!

Regards

Andy

Yes, you would need to look at schematic and see which channel is connected to high tone, and which to low tone. It would be nice to label the low tone disc1 and high tone disc2 for example on the PCB/schematic.

However you can easily determine this experimentally before you mount the pots in the enclosure. Other than the tones, the two channels are identical I believe so you can set them up (disc pot positions) any way you want by experimenting.

I would probably just mark 10 positions and experiment with targets to see where they discriminate.

Then I would probably set up my IGSL in one of many creative modes:

1. One channel detects iron, the other channel detects everything.

2. One channel detects the bottom 2/3 metals (iron, foil, nickel, pull-tab), the other channel detects
the top 2/3 channels (nickel, pull-tab, copper, silver). This gives:

a. low-tone = iron, foil
b. both tones = nickel, pull-tab
c. high tone = copper, silver

3. Both channels overlap on a single metal such as gold/foil

a. low = iron
b. both = foil/gold
c. high = nickel, pull-tab, copper, silver



Regards,

-SB

[der_fisherman]

IGSL Tones and Pot setup Units.

I think on our schematics and PCBs we should mark the non-wiper pot terminals with a meaningful symbol such as "min", "max" "CW", "CCW", etc. Might as well put "W" for wiper on PCBs.

Attached is a schematic for the TGSL where I put labels to give it a try.
-SB

Pot Direction
Hi Simon, you have given me a great starting point for my poti's direction with your TGSL schematic, many thanks.

By the way, you appear to understand the poti problem perfectly, so perhaps someone here can decide on a method for use on Geotech for such problems, one that is easy for anyone (even me!!) to follow.....your ideas seem to be good.

Pot calibration
After looking at SilverDog's new videos on YouTube showing the way that the tone varies with the target, I found another video that Ivconic has (fairly) recently posted, showing how he sets up his IGSL for foil using numbers for the poti settings!!!! I had seen it before, but missed the data under the video about poti setting.....

It's here:-

http://www.youtube.com/watch?v=MS9Tp2xw7RQ&feature=mfu_in_order&list=UL

What I found really interesting is that he tells us exactly how he setup his IGSL,
Quote:-

"Disc1 set on "5" , Disc2 set on "6"... Both Sens set on 75%...."

Fantastic Ivconic!!! Can you (Ivconic) throw some more light on how the Pots are marked to allow us to follow your example (like how many divisions 5 or 10 or what over the 270° (?) of the pot travel. It would allow us to compare our MDs effectiveness even better.

Percentage should be easier to work out assuming 0 to 100% over the 270° travel.

I still don't know from the schematic which adjustment is Disc1 or Disc2, but that cannot be too difficult to sort out!!

Many thanks Simon and Ivconic, some good stuff!!

Regards

Andy

[Qiaozhi]

Here are a quick couple of videos of my IGSL demonstrating the 2 tone operation

http://www.youtube.com/watch?v=6qSOc7SFc0s

http://www.youtube.com/watch?v=jGwnvoIKkj0

How does it react to a large rusty chunk of iron, such as a horseshoe?

[ivconic]

For more depths you should switch to Musketeer coil ....or to make DIY Tesoro DD coil.
Because, what is shown on your video is exactly what supposed to be the case with original Tesoro coil!
Bravo, nice job!

[ivconic]

Here are a quick couple of videos of my IGSL demonstrating the 2 tone operation

http://www.youtube.com/watch?v=6qSOc7SFc0s

http://www.youtube.com/watch?v=jGwnvoIKkj0

[silverdog]

IGSL 2 tones Video

Got mine working tonight, I love the 2 tones

I'm sure there is a bit more to come with a bit of fine tuning (considering I don't really know what I'm doing )

I'll get a video up as soon as I can

All thanks again to Ivconic for this project

Here are a quick couple of videos of my IGSL demonstrating the 2 tone operation

http://www.youtube.com/watch?v=6qSOc7SFc0s

http://www.youtube.com/watch?v=jGwnvoIKkj0

[simonbaker]

Dear Ivconic,

It would be great to know as to which end of the pots should be connected to which connections on the PCB.
The center wiper is easy of course, but should a signal increase or decrease when turning a pot clockwise for example
would also help. Perhaps a test point for the scope or meter?

Andy

I think on our schematics and PCBs we should mark the non-wiper pot terminals with a meaningful symbol
such as "min", "max" "CW", "CCW", etc. Might as well put "W" for wiper on PCBs.

Attached is a schematic for the TGSL where I put labels to give it a try.

For the ground balance pot I'm guessing how most people do it, and I labeled it CW and CCW for clock-wise
and counter-clock-wise. I hope others will review and give opinions.

I labeled sensitivity and disc pots with "min" and "max".

For min discrimination, it means accepting more metals, and max discrimination, less metals; you can decide
whether you want to use CW or CCW for min and max. I like CCW for min, probably most people do.

For sensitivity, min means less sensitivity to noise and target signals -- you need a larger target signal to make a beep.

If I labeled CCW on a pot terminal, it means that the wiper terminal makes a short (zero resistance) to that terminal
when the pot is in CCW position. Likewise for CW, MIN, MAX.

I hope I didn't get it wrong. The IGSL circuit has two TGSL circuits in it and the correspondings pots
can be found. It does take a little work to relate the schematic to the PCB, so it would save eyeball strain
and mental gymnastics if PCB makers could label the pot connections on the PCB with meaningful
labels (including W for wiper).

-SB

[der_fisherman]

Setting up an IGSL with no previous TGSL knowledge or experience....

Please read older posts (TGSL threads for example) and learn some electronics basics so you can THINK for yourself
Its ALL is ALREADY explined 100x times!!

Dear Habitbraker,

I have read TGSL forum several times (really interesting, enjoyed it and learnt a lot), I have also read Don Bower's excellent TGSL 101, parts I & II at least 4 times and used it even to build my coils (really good information).

I am sure that for anybody who has made and used a TGSL you are 110% correct, then the IGSL is easy. But for an electronics Engineer that has spent the last 40 odd years working only in "DIGITAL" electronics, who has not ever built a TGSL machine, its not quite so "cut & dried" as you obviously feel it is.....

Of course I know the building blocks, but I still don't understand the way it all hangs together in the manner that I wish to.

Some of the names elude me completely (does GEB mean "Ground Exclusion Balance? If yes, what does THAT mean????), even though I have built several IB machines over the last 30 years.....nowhere near as complex though as the IGSL.

You are sitting on the other side of the fence from me with your TGSL and IGSL knowledge, for you it is easy....try and be a little more understanding of the situation.....

The last time I was "immersed" in analogue electronics, it was all Tubes/Valves and I was setting up twin 4.5" gun turrets and Sonar equipment in the Royal Navy......(helps a lot with setting up an IGSL!!!)

By the way, you may be a useful Guy to know later, if you have actually built an IGSL, if I need any fine tuning for mine, is that OK with you?

By the way, have you actually built, tuned and used an IGSL? Or do you only have TGSL experience?

Thanks in advance for your help with my IGSL and have a great day anyway......

Andy

[habitbraker]

Please read older posts (TGSL threads for example) and learn some electronics basics so you can THINK for yourself

Its ALL is ALREADY explined 100x times!!

[der_fisherman]

Possible Setup procedure

Der fisherman, if you want correct answers - ask correct questions.
Write your post SHORTEST possible and ask directly what you want to know.
Otherwise...i don't see how can be answered and helped to you?
P.S.
Thanks Jerry! Best Regards!

Dear Ivconic,

what I would like if possible, is a short accurate setup procedure for an IGSL for each trimmer and pot. Also a recommendation for the nulling of the coils, as in TGSL build with best null possible, or some another value.

It would be great to know as to which end of the pots should be connected to which connections on the PCB. The center wiper is easy of course, but should a signal increase or decrease when turning a pot clockwise for example would also help. Perhaps a test point for the scope or meter?

Many thanks for your kind offer, if there is anything I can do for you in return, just ask. (Like finding those components you were missing a few months ago for example.)

Regards and have a great day

Andy

[Amalio]

Hello

Ivconic thanks, I change faraday cage, and incidentally reduce inductance.

regards

[ivconic]

Amalio your RX coil seems exactly as supposed to be.
Maybe you will need to lower a bit inductance at you TX coil?
Remove one or even maybe two turns.
0.97mH will be just fine.

[ivconic]

Hi Wiltran: Well I did that about a year ago and at the time USB cables were being experimented with so that is what I used on this one with good results.

The reason I made the graph in the first place was to try and figure out if there was a voltage or range of voltages inside of minimum null that I could use as a target and have the ground balance and discrimination work well without a lot of fussing with the scope.

As you can see, 20 degree phase shift leaves about 11 millivolts. At this point ground balance and discrimination work good. However, they still work with 27 degree phase shift at 4 millivolts.

Assume that 4 to 11 milivolts is a window in which GB and Disc both work, then it seem logical that you could split that range and set the null about 7 or 8 Mv. This would leave some wiggle room for movement as the epoxy cures and still be in a workable range.

That was the idea anyway but remember this is a sample of one coil and I may be just blowing smoke in the long run. This is why this test needs to be repeated on several coils.

Jerry

BTW: This was on a 20 Cm coil and was getting air test of 30 + cm with good discrimination while rejecting a ferrite bar.

Very nice said!
I also think that there is certain "window" or range in which DISC and GEB will work good.
And seems it is the range 4-15mV (approx.)
Yes i repeated this through making more than 70 coils for TGS/TGSL so far.
Most of those are nulled in range 4-15mV and maintained descent performances.
That is (you may say) proven already for TGS/TGSL coils.
For IGSL coils... yes it's same for IGSL version with TGSL coils, but yet not sure would it be the same "rule' for Musketeer coils version too.
Can't tell, because i used only original Musketeer coils so far..
Certainly; your observations are very correct, i agree.

[ivconic]

Der fisherman, if you want correct answers - ask correct questions.
Write your post SHORTEST possible and ask directly what you want to know.
Otherwise...i don't see how can be answered and helped to you?


P.S.
Thanks Jerry! Best Regards!

[der_fisherman]

I would like to add a little.

Ivconic brings something special in ideas and enthusiasm to this or any forum that is simply not here during his absence. Think about it. When he came back after about a year of silence, he put the IGSL out there for anyone and everyone to copy and build. This forum went from nothing to what it is now in just a few months. Quite an accomplishment!

His ideas and willingness to report his experiments, good and bad is why the TGSL thread is one of the biggest if not the biggest on Geotech.

Geotech is a gathering place if ideas rather than a kit building forum. It is up to each individual to do his own homework.

Jerry

Many thanks. That is exactly what I am going to do, no matter how long it takes.....

I was hoping for some tips from the "leader" of this forum, that is seemingly never going to happen, sadly.

I am hoping that Don might take up the challenge in his place......

Thanks for your kind words.

regards

Andy