BARACUDA-Legend-1

[Alexismex]

Bravo ....Apberg and thank you for your work it is good in Geotech to help and experiment all kind of PI ....
If you find a Tip 127 : you will see a different kind of result !!! in the response in audio mode that you can distinguishing a little the iron response over the gold and silver response "a must for this time".......(for the most slow delay i think) ...
like you see with a good coil (450uH and 1R5 ) to mach exactly the original the damping resistor (330R)..... BARACUDA will be THE winner in performance to many other ACTUAL PI detector ....
See also the switch name Sw1 for the Fet Q5 ....and have you noted the "smooth " threshold adjust !!!
Also in the original board the Fet Q3 and Q4 are not matched one is 5485 and the other is Mpf 102 perhaps is for something ??? or this day they do not have stock but i was thinking why they did not place 5485 for Q7 and have Q3 and Q4 the same MPF 102 ??'
Have a good time
Alexis.

[hispalba]

Hi, I do not find mps102 in Spain. can I replace by other?, maybe I can replace by bf244.
best regards

[smity]

video

There is a video of this device?

[ApBerg]

Hello Alex & Dom44

Thanks for update,s it is not your mistake ! I had placed the power regulater and not checked them 100 % ... for good orientation (getting old I think)
If I use 8 volt as power supplay the detector is working good.. ,with a higher 12 volt power its sens. is dropping and it gets unstable.
I have used for the pulspower a IRF 9640, think that that can be the problem ... to much power...( some 200mA consumption at 12v ) today I replace it by a TIP127 (if i have one) ..

Best regards.

Ap

Hello Friends,

Problem found... wrong transistor at the place from the 2n2222 the detector was working with it .... but gave the voltage problems...
Now with a good 2n2222 and the IRF9640 still in place it is working o.k.
This is a good beach detector I think, and can be made from very cheap parts !
For battery's it is very tolarant, works from 8 to 12 volts.
If you use the sprint layout file .. do not forget to turn the 78l05 and 79l05 180 degr.

Best regards.

Ap

[ApBerg]

Sorry i upload the good photo

Hello Alex & Dom44

Thanks for update,s it is not your mistake ! I had placed the power regulater and not checked them 100 % ... for good orientation (getting old I think)
If I use 8 volt as power supplay the detector is working good.. ,with a higher 12 volt power its sens. is dropping and it gets unstable.
I have used for the pulspower a IRF 9640, think that that can be the problem ... to much power...( some 200mA consumption at 12v ) today I replace it by a TIP127 (if i have one) ..

Best regards.

Ap

[Alexismex]

Sorry i upload the good photo

[Alexismex]

Hello is right for the regulators sorry i did not see the small layout in your printed circuit , just you need to inverted the transistor like in the Original is OK
If you print my hand layout in a transparent sheet you can cut and adjust alls the sheets....
See the photo of the original board is OK the regulators U5 and U6 is good place...

Also see in the original board you have one bridge for R15 and another bridge for R16 you can put some small resistor in place to stabilize the voltage but i think you do not need when you use nicad batery

[dom44]

Yes i foung that with mine it needs 12V for good performance and the error with the regulators is from the orriginal there in backwards there to.

[ApBerg]

Hello Alexis,

Made some corrections, send also the Sprint Layout file now.....but I have not build the board (yet) so there can be errors in it !

If anybody make's the pcb it is at his own risk !! (pfff.. I do not like this...) but I have no time to make the pcb in the next weeks ...

Best regards.

Ap

Hello Friends


It can have errors.....? IT HAS ERRORS... Have build the SPINT Layout board now there are some errors in the power part, the 78L05 and 19L05 both must rotated 180 degr.
Need some more testing, it looks like it is working now ..but the sens. is dropping if the batt voltage is going from 8 to 12 volts... later more...

Ap

[maikl]

Thanks for your reply dom44.This means Baracuda is better that the Surf.

[dom44]

no it is 20cm coil and 220uh was made for the chance metal detector.

[maikl]

ooooops befor some one pulls me up on it the transistor was the MJE2955 pnp complement and the coin is 25mm diameter

Hi dom44. Is it fast coil diameter 30cm?

[dom44]

ooooops befor some one pulls me up on it the transistor was the MJE2955 pnp complement and the coin is 25mm diameter

[dom44]

I also noticed something about this circuit the led is very dependent on the impedence of the head phones with out the right match the LED does not work correctly will light brightly if impedence is to low or not at all if to high.

[dom44]

With my detector i am getting about 30cm with a 2cm 20cent Australian coin clear but i am using a fast coil i built for another detector havent tryed it with the correct coil yet, and i used a MJE3055 transistor for coil drive, so iy has good performance for sure. here is a pic i have a 7905 temporarily in it till i get a 79L05.