BARACUDA-Legend-1

[kt315]

[kt315]

you ask general principles how-PI-work. do you need to read ITMD? ITMD is a some book released by Carl Moreland and George O. Carl Moreland is an administrator/creator of this forum.
also, you can find all theoretics you so needed in an article HAMMERHEAD PULSE INDUCTION METAL DETECTOR by Carl Moreland.

[Deghbar613]

i found this picture in the forum


from where can i adjust delay position .
and why move delay to this postion ?

https://www.geotech1.com/forums/forum/projects/baracuda-pi/8294-baracuda-legend-1/page10#post95849

thx all

[GeoMax]

Hello,
Perhaps the noise is caused by the cables in the wall, the fluorescent light, or the iron mat in the concrete floor, etc. – all possible sources of the problem.

[Deghbar613]

dirty test. delete metallic from around. for example, metallic nails in your table, corners etc. your coil must be hang in air on height 1+m. from roof 1+m.

I tested it outdoor the problem not there
indoor i am using this

[kt315]

dirty test. delete metallic from around. for example, metallic nails in your table, corners etc. your coil must be hang in air on height 1+m. from roof 1+m.

[Deghbar613]

Hello everyone
Finally, I have built the Barracuda, deep is good 27cm on a coin ,but when I move the coil, it makes a noise.
What is the solution?

[Deghbar613]

Oh, that's not good. I've heard this from other people too, that shops in Algeria sell fake ICs from China.

@Noise
I've taken a look at your PCB design. There's a ground loop on your circuit board. You should avoid ground loops. The ground loop might be picking up the noise. Just cut the loop somewhere. Also, the resistor in the negative terminal of the NE5534 is quite far from the actual IC chip. I would place it closer to the IC chip.

Thanks for advice GeoMax i will working on it
this forum is good for learing
Thx for all who help

[kt315]

the noise is not good but not bad. Eric Foster told his case he did seek a noise in his electronic board. very long time waste.
it turned out ... to a lamp in one of rooms. 'economic eternal lamp' gave this noise.

[GeoMax]

Oh, that's not good. I've heard this from other people too, that shops in Algeria sell fake ICs from China.

@Noise
I've taken a look at your PCB design. There's a ground loop on your circuit board. You should avoid ground loops. The ground loop might be picking up the noise. Just cut the loop somewhere. Also, the resistor in the negative terminal of the NE5534 is quite far from the actual IC chip. I would place it closer to the IC chip.

[Deghbar613]

From where have you bought your NE5534 IC chip?

From electronic shop here (algeria)

[Deghbar613]

The response decay is way too slow. I suspect a fake opamp.

Yes it's fake i changed it with lf356 null offset works perfect but there is lot of noise so i will try find original ne5534
but in datasheet lf356 slow rate is 12v/us and ne5534 is 13v/us i don't know from where this noise

[GeoMax]

From where have you bought your NE5534 IC chip?

[Carl-NC]

This is the waveform of ne5534 pin6 in video below

The response decay is way too slow. I suspect a fake opamp.

[Deghbar613]

the horizontal part of the signal must be sure lie on X axis. is it clear?

Yes
i need to change ne5534 i think it's fake
the others waveform i posted are they ok ?