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Originally posted by bernte_one View Posthello
i search for measure points to tune my baracuda with oszi
so please if somebody could tell me the best points
for example
coil damping value (for the case a potentiometer is inserted instead of resistor)
delay
offset
fine tune settings
regards and good night
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Hi,
I just finished my baracuda and is working with quick done search coil from 0.5 mm stranded pvc insulated wire on 200mm diameter with 29 turns.
Now i want to make a coil(with your's help) for small nudgets of gold ie. 3-4 gr.
I have some enamel copper wire 0.25mm and i wonder how would work if i do double winding with this wire on 200 mm diameter with 28 turns?
Sorry for my English.
Here some pictures:
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MPS 2222A
Q2 is MPS 2222A=PN 2222A and must be positioned this way(PCB is designed for metal case transistor)...it work's very fine without removing Q5 check out pins:Attached Files
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Hello Detecto, You will not be disappointed building the Baracuda. Excellent results can be obtained and easy project to build. I was very surprised at how well the bara preformed, with a good coil design it's amazing the depth of detection.
all the best
wizz737
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Originally posted by wallker View PostQ2 is MPS 2222A=PN 2222A and must be positioned this way(PCB is designed for metal case transistor)...it work's very fine without removing Q5 check out pins:Attached Files
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I was busy couple of days,but sunday is a day for barakuda
I will make a few turns for some coils,but after replacing TIP 127 (which is burned up when i was looking damping resistor value...) with some substitute...
What would you recomended for substitute ?
Best regards.
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Dear Nikolaj,
where are your damping resistor from your photo?
a) Please never testing your circuit without damping resistor (220-390R min.1W!).
b) We strongly recommended mounting the steel cooler plate in the TIP127(why use TIP127?)
From this position better an FET (for example IRF9640 & Co.)
These a) and b) parts are heats (approx 60 Celsius is normal , i think.)
My suggestions:
1) 555 Oscillator working? Not halted?
2) If working, please check the oscillator time period. if the period is very short (higher freq.)
it is quickly opening the power transistor, and battery current is higher
(The normal PI-s are uses approx 100-225Hz, sorry im dont remember the Barracuda freq. The battery power is concerning with freq. and tank capacitor, but approx 100mA is very good for metal detecting.).
3) Oscillator capacitor is good value? For example: in the drawing write is 47 nF, and you use 4,7 nF (check for your drawing for the correct values -- im dont remember.)
4) About oscillator part not an short circuit? For example: potentiometer connections, panel, etc.
Brg
Rumcajs
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Originally posted by bernte_one View PostFinished my double layer planar coil (blue one in the middle).
Results are good with very light threshold i got 2€ coin 30cm+.
Coil has 380mH and 2R8.
All what i need simple and small. Perfect for the playing yards in my neighborhood.
(I know i need a new frontplate after my external pots modded)
thanks to all for advice
good sleeping
could you post some more information about your coil(wire thicknes,number of turns,in diameter and od diameter).
Regards.
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Hi folks, Has anyone had success making a DD coil for the bara, I've read it's been done to the surf pi and work good. In this arrangement Would the inductance of each coil be same as a mono coil? example 450uf each coil or does the inductance of both coils equal a single mono coil inductance? Would the coils be wired in series? You're thoughts would be much appreciated.
Best Regards,
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Originally posted by wizz737 View PostHi folks, Has anyone had success making a DD coil for the bara, I've read it's been done to the surf pi and work good. In this arrangement Would the inductance of each coil be same as a mono coil? example 450uf each coil or does the inductance of both coils equal a single mono coil inductance? Would the coils be wired in series? You're thoughts would be much appreciated.
Best Regards,
my opinion is that for barra better to use coplanar coils. More information about those coils here:
http://www.geotech1.com/pages/metdet...planar_300.pdf
Best regards.
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Originally posted by wallker View PostHi wizz,
my opinion is that for barra better to use coplanar coils. More information about those coils here:
http://www.geotech1.com/pages/metdet...planar_300.pdf
Best regards.
I"ll have to figure out how to mod the Bara circuit to tie in separate TX & RX coil. I remember seeing a mod for the Surf to do this, I'll have to refer to schematics of both, I believe they are similar in design.
I have been experimenting with different coils for the Bara, so far best results are with a fast mono coil 9.5 inches diameter.
Thank you for sending thread for coplanar coil.
Best regards,
Best Regards,
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