Sandbanks

[dbanner]

What do you mean by latest schematic? There is only one original "sandbanks" project. But here are some others:

[bernte_one]

who has the latest shematic nad pcb layouts?

[Toros]

modified from PI Polones

https://www.youtube.com/watch?v=kbILR1xS_kg

inside
[ATTACH]38337[/ATTACH]

modified driver mosfet and sample delay, sample window

spec :
Freq : 200Hz
Pulse Width : 125uS
Sample Delay : 25uS
Sample Window : 50uS
Coil : 302uH


testing :
[ATTACH]38338[/ATTACH]

result:
[ATTACH]38339[/ATTACH]

I reviewed the video in the youtube. I wonder if in real terms I will have to search the same way: I slowly move the probe over the ground so that it detects the change in the sound of the detector. What area will I be able to search for one day this way?

[homefire]

The main issue with this detector was the Charge pump transformer availability.

Everyone tried to do a work around and or Mollestification to get around that simple issue.

We have pages after pages of people pulling they're hair out dealing with something so simple.

In actuality there are plenty of suitable replacement transformers available that are pin for pin functionally perfectly suitable to replace the thing.

Hell, I built a working transformer using the core of a IF transformer as the basis one time.

If people want the Sandbank , Build the SandBank as it was created.

Other wise there are a multitude of BETTER simple PI detectors to build.

What is it with Human Nature to Over Think and Complicate such a easy task ?

LOL

[gerson]

Hello . WAHYU, YOU HAVE THE SCHEME OF THESE MODIFICATIONS.

[Qiaozhi]

Hi guys, what parameters would be correct gor winding a 28cm coil i have a bunch of 28cm housings laying around.
For 25cm diameter 16 turns of 0.5 is good, what about 28cm coil? Are the parameters the same?

Try the Coil Calculator at the top of the Coils forum -> Coil Calculator

A 25cm diameter coil with 16 turns of 0.5 mm wire has an inductance of 204uH.
A 28cm diameter coil needs 15 turns to achieve an inductance of 206uH.
Personally, I would use either 18 turns (L=292uH), or 19 turns (L=323uH).

[maximusdesmus]

Hi guys, what parameters would be correct gor winding a 28cm coil i have a bunch of 28cm housings laying around.
For 25cm diameter 16 turns of 0.5 is good, what about 28cm coil? Are the parameters the same?

[Wahyu]

modified from PI Polones

https://www.youtube.com/watch?v=kbILR1xS_kg

inside


modified driver mosfet and sample delay, sample window

spec :
Freq : 200Hz
Pulse Width : 125uS
Sample Delay : 25uS
Sample Window : 50uS
Coil : 302uH


testing :


result:

[homefire]

The one using the PIC. It's really nothing like the SandBanks any more.

[Toros]

That think only has remnants of the Sand Banks in it. LOL

You talk about the schematic and PCB modification of Ivkonic, realized by Lucas Lab.

[homefire]

That think only has remnants of the Sand Banks in it. LOL

[Qiaozhi]

The original used the LM709. It was used for Freq Compensation. Pin 1 / Pin 8.

That's probably it. Although there should also have been a 1.5k resistor in series with the 10pF cap.

[homefire]

The original used the LM709. It was used for Freq Compensation. Pin 1 / Pin 8.

[homefire]

Looks like a Cap that may have been used with some other Op Amp.

[Qiaozhi]

HI
Can anyone explain what exactly is the role of the C7?
Considering the fact that Pin 8 in the op-amp LF357 is N.C!
tnx
[ATTACH]37389[/ATTACH]
[ATTACH]37390[/ATTACH]

It looks like a mistake to me. Here's the original Sandbanks article:

http://www.geotech1.com/cgi-bin/pages/common/index.pl?page=metdet&file=projects/sandbanks/index.dat

and it doesn't use an LF357. So I assume the PCB you posted is someone's modified version.