Simple Russian PI detector Pirat

[BKY1337]

Post #173 in this thread is my layout, i used 68k instead of 62k resistors, the ceramic cap is a foil capacitor and the transistors are BC558 and BC548.
12 Ohm instead of 10Ohm and the Mosfet is IRFP450, but i think this doesnt make much difference.

[BKY1337]

I used the version from hammerhead. The green and black picture with two pots (100k and 10k).
Thank you for the tip with the damping resistor.

I made a new coil 5cm diameter 46 Turns 0,3mm wire.
And im impressed with the results.

14 cm for a euro coin. And still a very good depht for bigger things and an acceptable depht for smaller things than an euro.
I need to make an enclosure for my board and the coil.

I use two trimmer pots now to test the board and its very stable.

[bernte_one]

ok this works for me
last layout.zip

[bernte_one]

try a variable damping resistor and find best working value (wire pot- Drahtpoti) later you can change it with a normal resistor, (read the best value from wire pot with multimeter and take fixed resistor the is next in the value), and a coil diameter of 25-30cm.

Which version of pcb did you use?

[BKY1337]

Excellent for this circuit.
I like the russian version more than the LM358.

I still need to make a better coil. I used the 15cm Diameter one from my BFO with about 12 Turns 0,3mm enameled wire.
I had 20cm with a 1 Euro coin, 1m with a pan, about 50cm with a spray can. 15cm with small brass things (female screw form Potentiometer).
I like the loud sound. I can adjust the detector more sensitive when its louder.

I also need to replace my pot on this board, 1M is too big.

Do you think a bigger Mosfet can make the detector stronger?

[bernte_one]

what is excellent depth in your opinion?
can you make a Video from your working detector?

[BKY1337]

My K157ud2 arrived and now everything works. The Op -Amp was damaged.
I changed the Mosfet with IRFP450 at this board and i have now excellent depht and the detector is very loud.

[dbanner]

I checked my Russian pirate build from two years ago, on my PCB between pins 6 and 7 of 555 chip should be resistor 1.5k not 15k otherwise schematic posted is good. I think I used a Darlington plus 8ohm speaker for audio. If you build coil according to specs I posted it will definitely work with good results.

[Andi68]

What an awesome joke

[homefire]

Boy, Piggy Backing a LM386 sure would be easier.

[6666]

How can i make my Pirat louder?


.

[Andi68]

Try it

[BKY1337]

Can i change R8 in your schematic to make it louder?

[Andi68]

I made this with the TL072, it works.

http://www.geotech1.com/forums/attachment.php?attachmentid=38935&d=1488134327

R9= trimmer 200k, R13 =pot 4,7k

I want it for a pinpointer

[BKY1337]

How can i make my Pirat louder?
I've heard that i can adjust this with R8 which is the 390 ohm resistor, but 390 is the maximum.

My original Pirat was a lot louder than the TL072 version.

Mine is very unstable by the way, i have to adjust it new when i turn it off.