Barracuda Legend Kit Problems

[Old cart]

Is the KT315 version of the BOARD or the schematics?
---
board = schematic. i did exactly layout of original, but in my opinion power lines was no so optimal and were retrassed in some places based on the concept of reducing interference&noise.

well it must have worked!

[kt315]

Is the KT315 version of the BOARD or the schematics?
---
board = schematic. i did exactly layout of original, but in my opinion power lines was no so optimal and were retrassed in some places based on the concept of reducing interference&noise.

[kt315]

thank you Godigit for nice report. try to tune frequency on exactly 600 Hz (enlarge R7 value). that has to decrease EMI interference.
can you give maxim412 opamp schematic you connected? i maybe will do a especial dip-8 submodule/board fitting opamp place with it...
also you may change R15 and R16 on inductors >80 uH (micro-).

[raygdunn]

Ray, I think all this would do is to increase the delay. Caps in parallel just add so 1nF plus 4.7 nF = 5.7nF. So did you match the main and EF pulse widths? That mod I mentioned really just adjusts the signal going to the samplers (main and EF) by adding
Resistance to make the channels match.

Hi Old cart,

Sorry I'm getting a bit behind with replies.

I've put some 100ohm pots presets on order. I've got nothing like that. I'm dubious about proceeding with much in the balance area, whilst the first sample pulse width varies with the Delay setting, though I do appear to have balanced things with the ceramic magnet at round about the optimum delay. With the detector balanced, I unearthed some low voltage batteries and did a field test. Yes it has eliminated the swing noise.☺

My capacitor experiment went wrong on two counts. I need to reduce the value, not increase it. That will shorten the current delay setting and then I can increase the Delay pots to compensate. The 40106 appears to dislike low value resistors. I'm thinking this would square up the leading edge of the first sample pulse and reduce the variation of its width (which upsets the balance of the two pulses to some degree). I'm having second thoughts on extracting another component at the moment☺

On my last component extraction, I found your tip about using a toothpick very useful, for clearing the hole. Some small new side-cutters also helped... Thanks.

Ray

[Old cart]

Here are some scope shots from my Barracuda Kt 315 version. Im on the road again and all of my testing has been indoors in bad EMI and also lots of rebar in the floor.
Performance depth is pretty much on par with most other posters. Nickle at 10 inches in bad Emi.
At first I thought the motion non motion did not work but turned out I needed to move the coil 4 feet off the floor due to the rebar. It picks up large metal very well but strangely only has a depth of 4 inches on all my other test targets from gold rings to coins all hit the same.


Tx Pulse
[ATTACH]35799[/ATTACH]
[ATTACH]35800[/ATTACH]

Tx and main sample delay
[ATTACH]35801[/ATTACH]

Sample delay and main sample
[ATTACH]35802[/ATTACH]

Earth field delay and main sample
[ATTACH]35803[/ATTACH]

Earth field sample
[ATTACH]35804[/ATTACH]

Pre amp out and voltage across coil. (maxim 410)
[ATTACH]35805[/ATTACH][ATTACH]35806[/ATTACH]

And here is a picture of the peramp out with my dual front end plug in made for the HH (maxim 412). I know its not optimized for the two circuits but boy does it change the threshold to a nice clean hum similar to a Vlf and not hardly effected by the noise in my test environment. Depth response is about the same but for the deeper targets its a threshold worble or drop. Target sample range also changes, Good only from 7.2 us to about 30us no response after that.
[ATTACH]35807[/ATTACH]
[ATTACH]35808[/ATTACH]

This post may be out a little out of place but it seemed relevant to the discussion on the schematics working or not.
I'm still learning and may be missing things but this board seems to work Just build it and power it up and calibrate it.
Went as smooth as my HH Surf pi or Mpp. All of these kits worked from the get go.
And thanks to you all for that!
Best
godigit

These look pretty good. Is the KT315 version of the BOARD or the schematics? I ask this because KT315's board appears to have been much better laid out than the original. The scope photos I have seen from his board are much better than other layouts. He has also done a better job of bypassing many of the IC's.
I want to emphasize that I have never said that any of these designs would not work, only that the some of the designs are not optimal for reproduction. Some will work, she may even work great, and some will break. The Baracuda certainly fits into this category.I think that given the vast differences in electronics background and debug skills our members have it is wise to have designs that are dead easy to build and have work.
In that regard maybe we should have voting buttons on each project that allows builders to give feedback on how easy it was build a design and get it working. EASY MODERATE HARD I NEVER got this to work!

[Old cart]

Best compromise with delay setting I could find. 12V battery 8.5 coil

~[ATTACH]35809[/ATTACH]
~[ATTACH]35810[/ATTACH]

All maxim threshold change while sweeping. Loud beep is approximately 1" less

Can get nearly 14" on the gold ring but then the fibula is down to 3"


If I was only going to use it at the beach I think I would tune just to the rings both would be a solid beep over 10" which is about the max you can easily dig out.


Not sure how low the battery can go before the delay settings alter but at 8.75V there is about 1/2 a turn of the trim POT difference with no warning.

That sounds normal if the fibula is small, say 1/4" or so in diameter.
Do you have a US nickel? Hard to tell from your pictures. That is a target I know well.

[ivconic]

Best compromise with delay setting I could find. 12V battery 8.5 coil

~[ATTACH]35809[/ATTACH]
~[ATTACH]35810[/ATTACH]

All maxim threshold change while sweeping. Loud beep is approximately 1" less

Can get nearly 14" on the gold ring but then the fibula is down to 3"


If I was only going to use it at the beach I think I would tune just to the rings both would be a solid beep over 10" which is about the max you can easily dig out.


Not sure how low the battery can go before the delay settings alter but at 8.75V there is about 1/2 a turn of the trim POT difference with no warning.

Precisely! Good job!
Heat sink is HUGE! No need for that.
"...Can get nearly 14" on the gold ring but then the fibula is down to 3"..."
Obviously.
Have you tried different delay for fibula?

[Koala]

Best compromise with delay setting I could find. 12V battery 8.5 coil

~
~

All maxim threshold change while sweeping. Loud beep is approximately 1" less

Can get nearly 14" on the gold ring but then the fibula is down to 3"


If I was only going to use it at the beach I think I would tune just to the rings both would be a solid beep over 10" which is about the max you can easily dig out.


Not sure how low the battery can go before the delay settings alter but at 8.75V there is about 1/2 a turn of the trim POT difference with no warning.

[godigit1]

What size battery are you using?

12 volt, never a blown chip and nothing is getting hot or even warm that I can tell.

[Qiaozhi]

What size battery are you using?

[godigit1]

Here are some scope shots from my Barracuda Kt 315 version. Im on the road again and all of my testing has been indoors in bad EMI and also lots of rebar in the floor.
Performance depth is pretty much on par with most other posters. Nickle at 10 inches in bad Emi.
At first I thought the motion non motion did not work but turned out I needed to move the coil 4 feet off the floor due to the rebar. It picks up large metal very well but strangely only has a depth of 4 inches on all my other test targets from gold rings to coins all hit the same.


Tx Pulse



Tx and main sample delay


Sample delay and main sample


Earth field delay and main sample


Earth field sample


Pre amp out and voltage across coil. (maxim 410)


And here is a picture of the peramp out with my dual front end plug in made for the HH (maxim 412). I know its not optimized for the two circuits but boy does it change the threshold to a nice clean hum similar to a Vlf and not hardly effected by the noise in my test environment. Depth response is about the same but for the deeper targets its a threshold worble or drop. Target sample range also changes, Good only from 7.2 us to about 30us no response after that.



This post may be out a little out of place but it seemed relevant to the discussion on the schematics working or not.
I'm still learning and may be missing things but this board seems to work Just build it and power it up and calibrate it.
Went as smooth as my HH Surf pi or Mpp. All of these kits worked from the get go.
And thanks to you all for that!
Best
godigit

[Koala]

This table was made by somebody else and tells a couple of stories.

Cheers thought I had a good compromise. Small hammered coin (14mm) at its maxim 6-7" (solid-faint) and Victorian Penney only lost an inch @ 9.5-10.5" and still had some discrimination. Fibula was still close to its max.

However when I went back to a gold or silver ring I was down to 8" down 3 inches.

Bit more testing needed but ran out of power in the batteries.

[6666]

What's a good target for testing/setting the delay setting.

If I set for maximum distance on a small gold ring I get poor distance on a small fibula. Where as if I set for maximum distance on the fibula a only loose less percentage wise on the gold ring.

This table was made by somebody else and tells a couple of stories.

[Qiaozhi]

What's a good target for testing/setting the delay setting.

If I set for maximum distance on a small gold ring I get poor distance on a small fibula. Where as if I set for maximum distance on the fibula a only loose less percentage wise on the gold ring.

That's normal. It depends what you're searching for.

[Koala]

What's a good target for testing/setting the delay setting.

If I set for maximum distance on a small gold ring I get poor distance on a small fibula. Where as if I set for maximum distance on the fibula a only loose less percentage wise on the gold ring.