IDX-PRO+VDI

[zoomix]

yes you can, there will be more sens to getting the vdi to work.. The down side is the diode - this limits the signal to 0.7v positive so on a reasonable target the vdi phse will read wrong as the diode clips the signal.

using a vdi on machines this simple is not really a great idea.

A gain control is needed to kepp small signals big and big signals small. Then clipping, or compression is eliminated, and real signal levels are maintained on disc and geb ch;s the result is a good phase number.

To do this u normally reduce the Tx signal when large targets appear. Or reduce th preamp gain as large targets appear.

on a beep no beep machine like idx, phase angle info was never designed in, as the diode limiter messes it up.

hello,

I do not understand much about the diode ... The IDX Version of silverdog without diode. Both VDI model That I do not make diode on the hand AOP.

Can you tell Specify qui diode You Because I am not an expert in analog electronics? Possibly the gold exchange needed to Improve?

thanks

[zoomix]

I understand that the VDI do not give deep

Some arrive a avoiry arrived:

https://www.youtube.com/watch?v=uaJNBRG0aQM

Thanks

[zoomix]

I understand that the VDI do not give deep

some get there:

https://www.youtube.com/watch?v=uaJNBRG0aQM

Thanks

[Koala]

I did not bother with a VID after reading the first part of the forum most people were only get good results at 50% of the depth of the machine. Even high end modern machines it should not be relied on as they can get confused by ground conditions depth and orientation of target.

When you get use to the IDX there is a lot of information from the sound as it is.

I don't bother as anything not iron i dig but you can get an idea of the target is by turning up disc and making a note of where the sign goes.


I have just been detecting a a field full of iron slag. I did just as well as some much more expensive machines. In fact some people found there machine all most unusable

[golfnut]

Well, I am close to finished.

The X and Y outputs look great on the Oscilliscope with the different XY Angle lines..
But, the signals are all under 0.25V - so too small to read accurately with Arduino only.

I tried the OpAmps circuit from page6 here, but the OpAmp outputs just looks like garbage on the scope now.

Can just I use the Outputs from U3B p1 and U3D p14 - instead of X and Y from u3A p7 and U3C p8 ?

yes you can, there will be more sens to getting the vdi to work.. The down side is the diode - this limits the signal to 0.7v positive so on a reasonable target the vdi phse will read wrong as the diode clips the signal.

using a vdi on machines this simple is not really a great idea.

A gain control is needed to kepp small signals big and big signals small. Then clipping, or compression is eliminated, and real signal levels are maintained on disc and geb ch;s the result is a good phase number.

To do this u normally reduce the Tx signal when large targets appear. Or reduce th preamp gain as large targets appear.

on a beep no beep machine like idx, phase angle info was never designed in, as the diode limiter messes it up.

[zoomix]

Okay, to read the next OpAmps on U3B p1 and U3D p14 ,
you need to adjust the DISC close to full on,
to get the proper readings.
Oscilliscope showed proper results now.

hello,

I realized for the VDI IDXpro and I had a problem with the distance. VDI gave me an answer but 5 or 10cm max. I checked with the oscilloscope and I saw that the signals are very weak.

For information, my IDX features an original 950loop coil and takes 1 euro to 40cm

I realized the DM-1 VDI lugateck and I have exactly the same problem.

I've seen video of the IDX + VDI or VDi lugatek that works perfectly. Response of VDI at the same distance as the detector ...

jlsilicon,

Do you have improved reading about VDI using X / Y on the output U3B p1 and p14 U3D?
thank you for your help

[jlsilicon]

Okay, to read the next OpAmps on U3B p1 and U3D p14 ,
you need to adjust the DISC close to full on,
to get the proper readings.
Oscilliscope showed proper results now.

[ampirate]

Well, I connected the Outputs from the U3B p1 and U3D p14 to the Oscilliscope.

But, all I saw was the same XY angle of about 45 degrees.
I tried Foil, Quarter, Ferrite, etc.
No difference.

The Metal Detector was calibrated, XY lines produced different Angles with different Metals.
I tested this before and after.

So, whats the problem ?

[peman]

I want to see the movie

[peman]

Hi please let movie

[jlsilicon]

Well, I am close to finished.

The X and Y outputs look great on the Oscilliscope with the different XY Angle lines..
But, the signals are all under 0.25V - so too small to read accurately with Arduino only.

I tried the OpAmps circuit from page6 here, but the OpAmp outputs just looks like garbage on the scope now.

Can just I use the Outputs from U3B p1 and U3D p14 - instead of X and Y from u3A p7 and U3C p8 ?

[golfnut]

A result then

[ampirate]

Finally got it figured out.
First, I extended the Coil from the Box by about 2.5 ft.
Which, got rid of a lot of false Detections.

Then, I replaced the RX Coil with one of correct size.
The TX Coil was 70cm circ while the RX Coil was about 60cm circ, but Inductance was the same.
This was causing a convergence of X/Y readings.
This also caused weird V-Arcs on the Plotted X/Y Readings (on the Scope).

Now I get clear differences between Slopes of different Metals.

[golfnut]

Dont go for lowest null value. It isnt important, what is is the phase relation of the preamp out WRT the Tx coil volts.

A good working unit looks like this

[jlsilicon]

Sorry, tired in the eyes when I posted it...
- 5mV and 20mV

not certain of your terminology?

Dont mix volts and amps !!

I would not do too much XY action at present..


Can you make the detector NOT BEEP on a pass with small chunk of ferrite ??

- If you cant, nothing else will be right either.

> Problem,
>
> I Null the Coils.
> I try adjusting the GEB.
> On the Y/X mode oscilliscope, I see:
> * Ferrite Rod vary between 10deg to 45deg depending on GEB.
> * but all Foil, Bolts, Nickel, Quarter, Silver Dime, Copper Penny are all the same at 135deg.
>
> Why ??
>
> Also, I get a lot better Sensitivity - if I shift (either way) off the Null of 5mA magnitude to about 20mA magnitude,
> but I lose the Ferrite to 135deg then also.