IDX-PRO+VDI

[eduardo1979]

Hi friend Excuse me, I'm not too good Anplysym. Wanted me to send final files to IDX-PRO metal detector parts and pcb. Grateful. [email protected]

60 cm for 1 € in the air is very difficult to achieve. It is the first the coil is and second integrated circuits U3 and U4. The U4 (LM393) is very delicate. I have tried many of them to get that. For the detector works very stable on the ground, a € 1 coin must be detected at 47cm in air. If you try to get more distance in the air, you can get, but in the field, the detector becomes very nervous and gives many false signals. With 47cm in the air for a € 1 coin, the coin buried 35cm without any problem is detected in soft ground.

[Schatztaucher]

hi friends soldering,

sooooo ....., yesterday's my silverdog kit comes. but before I do I want to solder it together again all the changes have been made to examine the idx. maybe you look about it again if everything was ok or if I forgot something. eduardo sorry if you're annoyed slowly
R24 = 2.2 MOhm (Mr.Bill)
R7 = 51ohm (Mr.Bill)
P5 = 10KOhm or 100KOhm pot (?)
VR3 = 1KOhm
R25 = 1KOhm Pot

regards

[eduardo1979]

hi friends soldering,

sooooo ....., yesterday's my silverdog kit comes. but before I do I want to solder it together again all the changes have been made to examine the idx. maybe you look about it again if everything was ok or if I forgot something. eduardo sorry if you're annoyed slowly
R24 = 2.2 MOhm (Mr.Bill)
R7 = 51ohm (Mr.Bill)
P5 = 10KOhm or 100KOhm pot (?)
VR3 = 1KOhm
R25 = 1KOhm Pot

regards

You can test the values of Mr. Bill. I like mine. For my part there is no problem.

[hugo]

Dont forget my IGSL used to play up on wet grass too.

I dont think the rC filter pole highlighted is to help with wet grass

S

I've found this in an old post :

One other little note, Tesoro uses the ground balance control to adjust both the phase of the sample AM channel and the R channel. However, they are offset very slightly by addition of a cap at the FET (a 10 pf on some prints). This little phase shift assures the hotrocks do not give false signals in the disc mode. So, when the ground balance is correct when listening to the AM signal, the R channel is offset just a little and is slightly postive. This cap cannot be eliminated but can be reduced in value a little make the R channel closer to the AM channel. In doing so, one will get a very slight increase in sensitivity but will also get false signals from some hotrocks such as magnetite.
Most manufacturers incorporated this feature of a slight offset to reduce complaints of false signals from rocks.
Reg

Maybe, it's a clue for wet grass and hotrocks !

Regards,
Hugo

[golfnut]

Hi Hugo, when the wet grass was mentioned - it was also mentioned that in order to move the problem onwards some more info was required.

Info such as, was the GEB CH tripping the comparator or was it the DISC. Or Both etc..


Yes it is good for discussion , but no amount of speculation will eradicate these problems without a structured engineering approach.

Where are we , where do we want to be, how do we get there, are we there - if so stop etc

As these simple machines can only integrate out one target phase - eg ground it is a challenge to integrate to zero additional phases of targets on the same channel - eg wet grass.

I dont know if this has been done, if you had more gating of the Rx signal additional to the existing det - whether this could apply a second chance to integrate out an unwanted target phase.

e.g.

[golfnut]

Meter VDI

After watching Dons oscillocope You tube of the IDX with both ch on an XY scope plot -showing target phases - without carrying a scope or making LCDs work in software etc.

I wanted a fast to produce and clear way to view Target phases on realy poor site I have a permission on. Huge Iron slag infestation from local foundy waste - plus natural iron mineralised soil.


I figure that other detector guys had same problem and have moved on - stuff may still be in there as Rx swamped, real tagets being masked by large falsing.


I want to SEE target phase on all targets not just hear same tone for real target and large iron...



Yesterday I took time to make a pair of analog VDi meters on the IDX.

I put one one each channel - GEB and Disc - The geb one is great for visualising the GEB setting as as you swipe a ferrite and can notch meter to zero ..


Its early stage but I can see that

Air Test

Symmetrical meter movement- both move together same direction
1)Rusty Iron slag - (no tone)
2)clean - high carbon steel - ( odd small clip tone one way - almost never)
3)Rusty steel - (Disc meter movement a little more jumpy - can trigger tone)
4) With very large Iron - golf ball size - ( Jumpy erratic Disc meter - when swamped - settles to symmetrical meter movement when raise to coil to reduce signal level)

Asymmetry in meter movement - flip in different directions - really easy to see
1)thin brass - tone
2)roman bronze - tone
3)9CT gold watch back 12mm dia - tone



Unfortunately a mod to one of the VDI amp channels resulted in a slow oscillation of the meter needle which I need to fix.

I need to build a fresh board and get it decoupled and fitted to my box as an add on - with the meters on.


I used a log amp with transdiode to give about 100dB dynamic range - So real targets give you something to see and an anvil just endstops the needle.

I will post if works well.

S

[Schatztaucher]

my idx detected. not really good, but that's a setting thing I think.Next time I will do everything to build the housing. then get photos and a clip of the function.

regards

[Davor]

Hi all,
Mr. golfnut have triggered my curiosity to check this IDX once more, and I found something unholy there. IMHO the phase of a pinpointing channel is wrong, but then again, I may be completely wrong in such assessment.
So, does anyone use pinpointing of this rig? How? Does it work meaningfully? Is there any video of this particular rig showing pinpointing action?

[eduardo1979]

Hi all,
Mr. golfnut have triggered my curiosity to check this IDX once more, and I found something unholy there. IMHO the phase of a pinpointing channel is wrong, but then again, I may be completely wrong in such assessment.
So, does anyone use pinpointing of this rig? How? Does it work meaningfully? Is there any video of this particular rig showing pinpointing action?

http://www.youtube.com/watch?v=JXBg8Z-GkkE&feature=plcp

[Davor]

There is a point in video where a PCB is turned, and I guess the pinpointer engaged, but it does not show what happens with the target against the coil. My guess is that the reading will be inverse, e.g. maximum beyond the rim of the inner coil, not middle. I can live with inverse, and I guess everyone else having such a detector will learn to use it that way. I just wish to have it confirmed.

[golfnut]

Disc mode

I notice the disc and Geb Ch signals are in antiphase.. I thought they should go the same way to trip comparator AND logic.


On my unit the Disc Ch signal goes negaitve with a small positive either side - hence I get 2 beeps each way for Non Fe..

Odd - is this normal?

[Davor]

Try swapping the Rx coil input wires, that should sort it out.

My question is about the pinpoint mode - does it give double beep?

[ivconic]

Try swapping the Rx coil input wires, that should sort it out.

My question is about the pinpoint mode - does it give double beep?

Yes he should swap TX or RX leads, depends how he wired his coil.
...
PP mode at IDX is nonmotion and can be adjusted with treshold trimmer, meaning; it gives continuous tone when detecting.
...
Main drawback at Classic 3 (IDX) is masking problem.
Just put coin or ring on mineral (or hotrock or what ever was that stone on video) and it will be completely masked.
Not to mention piece of iron close to coin or ring.
But that again will remind us on story from other thread; about half and full wave demodulators.
Except that; Classic 3 (IDX) is pretty awesome machine, deep, calm and sensitive.

[Davor]

I am aware of the continuous tone, but even that one has some highs and lows, and I just wonder where they are. My humble guess is that there is a minimum in a middle, and I wish to confirm that. I'm considering using a spare GEB channel in my IGSL for the same purpose, and I really wish to see this pinpointer in action.

BTW, this design, same as TGSLIGSL has somewhat odd compression by my standards. Given more symmetry it would reduce masking. My modded IGSL gives distinctive non-Fe beeps for each of the brass bolts on an old rusty knife, and that says something.

[ivconic]

I am aware of the continuous tone, but even that one has some highs and lows, and I just wonder where they are. My humble guess is that there is a minimum in a middle, and I wish to confirm that. I'm considering using a spare GEB channel in my IGSL for the same purpose, and I really wish to see this pinpointer in action.

BTW, this design, same as TGSLIGSL has somewhat odd compression by my standards. Given more symmetry it would reduce masking. My modded IGSL gives distinctive non-Fe beeps for each of the brass bolts on an old rusty knife, and that says something.

You bet it says something!
You discovered now why i decided to leave TGSL and make IGSL instead!
Exactly just because of the same damn masking problem as IDX is having too.
My approach is kind a odd, i admit.
Instead trying to make it with full wave demodulator i picked another approach.
What i want to say: IGSL should act as you are describing, that was the point.
Mixing various positions of those two Disc potentiometers you should be able to get exactly what you are explaining.

"..I am aware of the continuous tone, but even that one has some highs and lows, and I just wonder where they are. My humble guess is that there is a minimum in a middle, and I wish to confirm that..."

Yes, it is nonmotion, continuous tone, affected and adjustable by Treshold command. But i don't understand what are you meaning by " minimum in a middle" ?
As signal rises, tone rises too, if that's what you mean?