My Barracuda works ... but not very well.

[Watanabe]

My Barracuda works ... but not very well.


Depth of detection too small (1euro x 10cm).


Background noise too high... even adjusting the threshold is a very uncomfortable noise.


Any suggestions to eliminate background noise and or increase detection distance?


Using TL072 instead of LF412. Does that interfere too much on the threshold?


Coil is 1.0 OHM; 325uH; 23cm (diameter); 22AWG; 22turns. R1 = 330 OHM.


Thanks.

...

[ripsdevala]

Coil should 450uh with 330ohm 5watt resistor

[Qiaozhi]

My Barracuda works ... but not very well.


Depth of detection too small (1euro x 10cm).


Background noise too high... even adjusting the threshold is a very uncomfortable noise.


Any suggestions to eliminate background noise and or increase detection distance?


Using TL072 instead of LF412. Does that interfere too much on the threshold?


Coil is 1.0 OHM; 325uH; 23cm (diameter); 22AWG; 22turns. R1 = 330 OHM.


Thanks.

...

I assume you have built the Geotech Baracuda, and not the Apberg version?

[Watanabe]

Nothing improved ......

...

[Watanabe]

Yes. Geotech Baracuda - REV-A.


...

[Qiaozhi]

Yes. Geotech Baracuda - REV-A.


...

You should be getting a lot more depth.

Some things to test:
1) Check the +5V and -5V supplies are ok.
2) Take the detector outside (somewhere with less EMI) to see if the background noise goes away.
3) Fit an LF412A for U7, as specified in the parts list.

Do you have an oscilloscope?
If not, then this will be very difficult to debug.

[Watanabe]

You should be getting a lot more depth.

Some things to test:
1) Check the +5V and -5V supplies are ok.
2) Take the detector outside (somewhere with less EMI) to see if the background noise goes away.
3) Fit an LF412A for U7, as specified in the parts list.

Do you have an oscilloscope?
If not, then this will be very difficult to debug.

OK thanks.
I'll check.
I have an oscilloscope.

...

[willydp]

Feedback?

No update?
Didn't you use the step by step manual....check every step before continuing?
http://www.silverdog.co.uk/shop2/index.php
Left handside see library or click link that starts the download pdf.
Geotech Baracuda Build Guide

Enjoy

P.S. No publicity intended

[Tibuck19]

im also having issues , everything works, Depth is good but it only works with a piezo speaker. I might have an issue with step 8 and 9 ?

[Qiaozhi]

im also having issues , everything works, Depth is good but it only works with a piezo speaker. I might have an issue with step 8 and 9 ?

If it works with the piezo, then it should also work with a speaker or headphones.

[Tibuck19]

If it works with the piezo, then it should also work with a speaker or headphones.

It should but it doesn't hahaha, its almost like the speaker is asking for two much power, I hear a the power supply asking for more energy when I use the speaker. its like it inverted somehow when the speaker is plugged in, the sound drops when an metal object is passed over the coil. but I did do a boo boo , I put Q4 in backwards, I might of blown in ? maybe why its not working with a speaker ?

[Tibuck19]

Actually I do seem to struggle with Film Caps, perhaps you guys can look at the photo and make sure I didn't them up. EDIT: also I can only set the null pot to 0V off pin 7 and not 6 as mention in the build guide.

[Qiaozhi]

[ATTACH]40213[/ATTACH]

Actually I do seem to struggle with Film Caps, perhaps you guys can look at the photo and make sure I didn't them up. EDIT: also I can only set the null pot to 0V off pin 7 and not 6 as mention in the build guide.

The measurement should definitely be made on U2 pin6, not pin7. Pin 6 is the output, whereas pin 7 is the +5V rail.

[Tibuck19]

The measurement should definitely be made on U2 pin6, not pin7. Pin 6 is the output, whereas pin 7 is the +5V rail.

you are right, I was counting the pins wrong and added one, my 8 pin ic had 9 for a while hahaha