IF YOU HAVE MAKE , TRY THIS .

[sisco]

Hi Geo ,

In home , I can only use small coil (home armature , metalic desk , chair

leg , .....) .

try this , I test yesterday and work very well.( with original minipuls-3 ,

(12 volts battery and one V-mos):

1- use AD844 for U3

2- replace R7 & R8 with 10 ohms resistors.

3- connect 33nF MKT and 220nF MKT (parallel) capacitors between pin 4

U3 and GND and between pin 7 U3 and GND (two capacitors parallel with C7

and two capacitors parallel with C8 .

you can test with this change and see yourself this metaldetector with

small coil can detect 50*50 cm metal plate morethan 120 cm distance .

[Max]

Hi Geo ,

In home , I can only use small coil (home armature , metalic desk , chair

leg , .....) .

try this , I test yesterday and work very well.( with original minipuls-3 ,

(12 volts battery and one V-mos):

1- use AD844 for U3

2- replace R7 & R8 with 10 ohms resistors.

3- connect 33nF MKT and 220nF MKT (parallel) capacitors between pin 4

U3 and GND and between pin 7 U3 and GND (two capacitors parallel with C7

and two capacitors parallel with C8 .

you can test with this change and see yourself this metaldetector with

small coil can detect 50*50 cm metal plate morethan 120 cm distance .

Hi Sisco,
have you tested it outside in real search conditions ?
If so, what's its behaviour with ceramics ? Do it detect fired ceramics ?

You could do that test on bench using a small brick fragment, say like sized as cigarette box.

Best regards,
Max

[sisco]

Hi Max

i don't know why you love ceramic and brick ?

you don't see my photos ? really I don't need to detect ceramic or brick .

if my detector sensitive to ceramics or bricks really I am Unhappy because I

can't find anything.

[Max]

Hi Max

i don't know why you love ceramic and brick ?

you don't see my photos ? really I don't need to detect ceramic or brick .

if my detector sensitive to ceramics or bricks really I am Unhappy because I

can't find anything.

Hi Sisco,
I've seen your pictures and understand you so much,
I don't like bricks , ceramics etc... cause they make me crazy when use my PI detectors on some interesting places. I have ceramic detection in some very good places and that's a bad thing.

There I can't use my PI detectors as you indicated.

It's because some bricks have iron-oxides inside that are detected by PI machines.

That's why I asked you about MiniPuls and ceramic: I'm interested in new PI designs but don't want to make another PI machine that detect again also bricks, just like others, that I already I've built, do.
Because if detect bricks is useless on the field for me.

Best regards,
Max

[1843]

Hi Max,

I know you have problem with bad SISCO's English understanding!

Try this PI and enjoy... it isn't sensitive to ceramic!

Best regards

[sisco]

Hi 1843 ,

you make this or not ?

can help me for make better this ? (like AD844)

and can test AD8055 in this detector because I try two month for find Ad8055 but can't find this.

[Max]

Hi Max,

I know you have problem with bad SISCO's English understanding!

Try this PI and enjoy... it isn't sensitive to ceramic!

Best regards

Hi 1843,
fine I've find time to make it!
have to leave GSabre in the middle till next week!

But your words are nice: "it isn't sensitive to ceramic" COOL!

As far I've tested:
- 2 Stuart's
- DeltaPulse
- XR-71
- GS4

All failed in my search conditions! Also other stuff (bought devices) tested but same problem... and sometimes also VLF fail there !

Read an old post by Eric Foster in his forum where he said was impossible to avoid that problem in PI where there are too fired ceramics around. All true, my experience is proof of that!

But I think that right timings could overcome problem!

What about timings of it ? Have you ?

With many thanks,
Max

[Max]

Hi 1843,
found that 1st delay is 150uS, not good for me.

I need a sensitive detector for small objects, not for big objects at depth.
That's why it's insensitive to ceramics !
I know... even delta at 120uS cannot see any fragment the size I've indicated!

No way! As Eric said.

Really sad thing that you couldn't make a good PI for small objects that rejects unwanted ceramics signals.

Anyway, thanks.

Kind regards,
Max

[sisco]

Hi Max

I test my minipuls in best adjust (after 30 minute adjusting ) with small coil

, and can detect one coin (2.8 cm dia) at 32cm .

this is not bad (I told why can't test large coil but think for small object like

coin , small coil is better) .

what you think ?

[Geo]

Hi Max

I test my minipuls in best adjust (after 30 minute adjusting ) with small coil

, and can detect one coin (2.8 cm dia) at 32cm .

this is not bad (I told why can't test large coil but think for small object like

coin , small coil is better) .

what you think ?

Of course small coil is better for small objects and the detecting distance of your minipuks is very good. Don't looking for anything else
Regards

[Geo]

Hi 1843,
found that 1st delay is 150uS, not good for me.

I need a sensitive detector for small objects, not for big objects at depth.
That's why it's insensitive to ceramics !
I know... even delta at 120uS cannot see any fragment the size I've indicated!

No way! As Eric said.

Really sad thing that you couldn't make a good PI for small objects that rejects unwanted ceramics signals.
If Eric says then it is true
Anyway, thanks.

Kind regards,
Max

Hi Max .
What are you looking for???? You can reject the ceramics with delay >70us.
But you will lose small objects especially gold. So my friend don't looking for anything else........... it does not exist.
Regards

[Max]

Hi Max .
What are you looking for???? You can reject the ceramics with delay >70us.
But you will lose small objects especially gold. So my friend don't looking for anything else........... it does not exist.
Regards

Hi,
Yes, right!

It's just another dream here!
I know, Eric said it's impossible years before.
And if he said that... I trust him.

I'll use a bigger first delay... and lose some gold.

At the end in that conditions is better having a good VLF and GSabre is a good candidate.

Best regards,
Max

[sisco]

Best adjustment

For find coin more at 30cm you must do these :

1-first do anything I told in my post (about AD844).

2-use 100 ohms trimmer and connect two heads of trimmer between pin 1

and pin 8 AD844 and middle heade of trimmer connect to pin 7 AD844.

3-disconnect coil and remove microcontroller ( ATmega8 ) and remove R6.

4-turn on meteldetector . use ossiloscope and connet to pin 6 AD844

and adjust trimmer for zero out.

after do these and adjust RANGE and TRESHOLD potentiometers (my

POWER and GAIN potentiometers always is last degree) you can with

small coil detect small coin more at 30 cm.

be successful.

[sisco]

Of course small coil is better for small objects and the detecting distance of your minipuks is very good. Don't looking for anything else
Regards

this metaldetector very good but have a little BIG problem .

this is not good sensitive to gold .I don't know why but for detect

silver,copper,iron,brass,...work 100% , but for gold ~20%.

can tell me why ????????????????????????????????????????????????

[1843]

this metaldetector very good but have a little BIG problem .

this is not good sensitive to gold .I don't know why but for detect

silver,copper,iron,brass,...work 100% , but for gold ~20%.

can tell me why ????????????????????????????????????????????????

This is the issue that I don't like these PIs... It depends on bad designing...