Pinpointer - Minimax-PP II

[paku]

What is replacement for BC556

[Virdi_248]

Created my minimax, it works great except it gives false signals with moist soil and it was impossible to use in the field.


Any idea to solve the false signals?

[samii]

lay file, schematic looking same with Zomby version.
http://www.hobbielektronika.hu/forum...27.html?pg=190

[kt315]

and what? I again repeat you - THE AUTHOR IS PETRUCHO, RUSSIA. I give DIRECT LINK http://www.md4u.ru/viewtopic.php?f=19&t=6001

[FatBob]

I made this but didn't have a Peizo with oscillator inside so I modded the circuit a bit;



My first coil using 31 AWG and around 500 turns made 120V P to P at 8.2 Khz. I unwound some
wire and got 160V P to P at 9 Khz. So I rewound with 30 AWG. Now I get 15.5 Khz at 15.7 V.
The range is about 1". But I didn't realize it was a motion device.

So I bought a Chinese designed one on Ebay for $25. Say's it's static mode but claims 1.5"
range and then 10mm on Nickle and 25mm on quarter. Not sure if that's enough...

[bernte_one]

for a simple and good pinpointer build latest Version of malysh fm2 from Eddy71
it hast two tone and is very simple to build

[nonkapo]

Bernte,areyou reffering tp this one?

http://radionics.ucoz.net/publ/metal...tallov/3-1-0-2

[kt315]

http://smartelectronix.biz/publ/sleg...2_quot/1-1-0-3

[kt315]

Bernte,areyou reffering tp this one?

http://radionics.ucoz.net/publ/metal...tallov/3-1-0-2

https://www.facebook.com/eddy.com.ua/

[Nandor]

Really nice little project, works on first start.
I have made 2 versions, one with active piezo and another with a tone generator. The passive piezo is taken from my PC and it's driven with a CD4060+64kHz quartz oscillator generating 1kHz square wave for the BC547 transistor and that drives the piezo. The detection distance is about 4 centimeters for each circuit.
It is a very coil tolerant pinpointer, works with many ranges but with different sensibilities.
Here are my files and videos

https://youtu.be/wYtqIjXI6eI Original schematic.

https://youtu.be/OrosRtwkOho With the tone gerenator.

[Eddy71]

That's an interesting sound. I thought the parrot was screaming.

[Nandor]

You know what? I will call this pinpointer The Parrot!
I cant wait to hear it finding some coins.

[Koala]

Before you epoxy it up. I would check outside

I have built several pinpointers. None have worked as well as a commercial.

They are fine 100% on the workbench and not too bad at finding cables or pipes in the wall.

But useless when searching a dug hole. First it nearly always detects the hole. So switch it on close to where I need to pinpoint to recalibrate.

Change its direction to check the other side of the hole and it starts to go wild. Also detects the bottom of the hole if its damper.

Guess its my coils. Do they need to be shielded ??

Its not the ground as a cheap GP Pinpointer is fine

[Nandor]

Interesting observation Koala!
Well it's getting nervous if I touch it surely needs some kind of shielding for parasitic capacitance. The most difficult part for me is to find the proper housing for it.
The legend says that this circuit works also with LM358, just a little components change is needed.

[MartyJ1963]

Thanks for the files Nandor,,,What are the coil specs for this design please? Thanks and regards, Marty