BARACUDA-Legend-1

[mohandes]

Using cat5e cable is fine but make sure its a good quality solid copper type which is around .4mm with good thickness insulation round each core , allot of cat5e cable been sold around is cc type which is crap , cc copper clad which is normally alloy coated with thin layer of copper.
I made a good coil out of .5mm LTC wh1003 cable which is stranded pure copper instrument cable.

thanks.
i buy a lot cable , cate6 , cate5 , copper wire 0.2 to 0.71mm and make a lot coil .
in all of i get better result with copper wire , for example i use the same coil for DP but copper wire get me more result about 3to5cm in air test .maybe the LAN cable have bad quality , maybe.
i search in net for .5mm LTC wh1003 cable but can not find it.
about coil shielding , what is your idea and what is your experiment ?
Excuse for my English.

[satdaveuk]

Using cat5e cable is fine but make sure its a good quality solid copper type which is around .4mm with good thickness insulation round each core , allot of cat5e cable been sold around is cc type which is crap , cc copper clad which is normally alloy coated with thin layer of copper.
I made a good coil out of .5mm LTC wh1003 cable which is stranded pure copper instrument cable.

[mohandes]

Also worth keeping in mind don't make the common mistake of winding to tightly because otherwise you will not only increase your inductance but also the coil capacitance, made alot of duff coils in the past due to that simple mistake.
Just firm and even pressure while winding.

so lan cable better ?
an you put here image of coil winding to teach me .
regards

[satdaveuk]

Also worth keeping in mind don't make the common mistake of winding to tightly because otherwise you will not only increase your inductance but also the coil capacitance, made alot of duff coils in the past due to that simple mistake.
Just firm and even pressure while winding.

[mohandes]

This type, cheapest possible thing from nearest flea-market. For detectors like barracuda avoid too high inductance, some 300uH is good target point, resistance is not too critical, 1.5-2R is typical value, don't add anything in series. Coil capacitance can be determined by measuring SRF- self resonant frequency for known inductance, already described on this forum.

many thanks
sorry me , how can i measure SRF ? please tell me.
regards

[Tepco]

which model :

https://www.google.com/search?q=2x+AWG20-23&client=firefox-a&hs=Zqa&rls=org.mozilla:en-US:official&channel=sb&source=lnms&tbm=isch&sa=X&ei=2whgU66kMdWxyASF5IGwBQ&ved=0CAsQ_AUoBA&biw=1024&bih=625#channel=sb&q=AWG20&rls=org.mozilla:en-US:official&tbm=isch

about Resistance of coil , if res of coil between 1to 1.7ohm and 430mkh it is good coil ? ( for example coil should be 2.2 ohm to 4 ohm and 400 to 450mkh )
can we add 1ohm 5w in series with coil , for add res of coil ?
how can we measure capacitance of coil, and reduce that ?
excuse for my English

This type, cheapest possible thing from nearest flea-market. For detectors like barracuda avoid too high inductance, some 300uH is good target point, resistance is not too critical, 1.5-2R is typical value, don't add anything in series. Coil capacitance can be determined by measuring SRF- self resonant frequency for known inductance, already described on this forum.

[mohandes]

Try to find smaller possible diameter (larger gauge ) speaker wire, awg18 is unnecessarily large. Cheapest possible type, actually not good for speakers at all (high resistance) but very nice for coils, usually 2x AWG20-23 and some 2mm plastic insulation two wire cable, both wires in parallel. So, less cooper and more plastic is better for this (to avoid unnecessary metal inside coil and reduce parasitic capacitance), resistance will be still OK, target around 30 turns, or around 300uH (250-350) if you vary geometry. Your coil calc. is probably wrong, measured inductance will be somewhat lower. For really fast coil, avoid cable and connection, just leave some 1.2m speaker wire from both ends of the coil and twist every 2-3cm. After proper damping resistor selection and minimal delay adjustment you will be very pleasantly surprised with results.

which model :

https://www.google.com/search?q=2x+AWG20-23&client=firefox-a&hs=Zqa&rls=org.mozilla:en-US:official&channel=sb&source=lnms&tbm=isch&sa=X&ei=2whgU66kMdWxyASF5IGwBQ&ved=0CAsQ_AUoBA&biw=1024&bih=625#channel=sb&q=AWG20&rls=org.mozilla:en-US:official&tbm=isch

about Resistance of coil , if res of coil between 1to 1.7ohm and 430mkh it is good coil ? ( for example coil should be 2.2 ohm to 4 ohm and 400 to 450mkh )
can we add 1ohm 5w in series with coil , for add res of coil ?
how can we measure capacitance of coil, and reduce that ?
excuse for my English

[mohandes]

Way too slow and strange looking, what coil type you use? Amplitude is too low, check +5\-5V supply, also scope probe and compensation. Can you adjust DC offset?

no
this is for piking PI . i look and it is bad it is not lower than 15mks and nulling not 0v.
excuse for my English.

[Tepco]

Quick test coil specs (used the coil calc):
inner radius - 4.75"/120.65mm (9-1/2" coil)
wire - 18 awg/1.020 (blue pvc coated speaker wire)
Turns - 28 = 488mH

Try to find smaller possible diameter (larger gauge ) speaker wire, awg18 is unnecessarily large. Cheapest possible type, actually not good for speakers at all (high resistance) but very nice for coils, usually 2x AWG20-23 and some 2mm plastic insulation two wire cable, both wires in parallel. So, less cooper and more plastic is better for this (to avoid unnecessary metal inside coil and reduce parasitic capacitance), resistance will be still OK, target around 30 turns, or around 300uH (250-350) if you vary geometry. Your coil calc. is probably wrong, measured inductance will be somewhat lower. For really fast coil, avoid cable and connection, just leave some 1.2m speaker wire from both ends of the coil and twist every 2-3cm. After proper damping resistor selection and minimal delay adjustment you will be very pleasantly surprised with results.

[Tepco]

HI dear Tepco
what is your idea for this wave ?

waveform.JPG

Way too slow and strange looking, what coil type you use? Amplitude is too low, check +5\-5V supply, also scope probe and compensation. Can you adjust DC offset?

[mohandes]

Hey sinclairuser,

I did catch that about the 500 ohm pot, thank you for letting me know.... it was to late for an edit when I came back...

I'm gonna swap some parts around once I get that cap I have been waiting for to try some of the different ways and keep testing this board..

Mohandes, I have been testing with a few different surf pro coils (330 to 350mH) I have made for testing, they seem to work ok with the barracuda. Yesterday I wrapped a 9-1/2" (241.3mm) coil out of 18 awg (1.020mm) speaker wire I had laying around, used 28 turns for 488mH and it seems to work pretty well considering its just a loose bundle. I think once I refine it, it should be pretty good. I plan on making 10 to 12 different test coils of varying inductance for testing purposes from 280mH up to 585mH so I can better fine tune the board/coil combination with a specific coil inductance. Lots of variables to play with...

The speaker wire test coil I made yesterday ended up giving (in Air) 9" inches on a US 25¢ and 13" inches on an Australian 20 coin ($?), US 10¢ @ 8" inches, a US 1¢ penny @ 10" inches, a US 5¢ @ 7 inches, a ladies 18k gold ring at 8" inches, a beer bottle top at 12" inches and a crushed pespi can @ 30" inches. I'm happy with the results so far although I think once I find the right combo this barracuda will really kick some arse... I'd like to get the nickel and the gold ring (Silver&Gold) depths a little better so I'll keep fiddling with things to see if I can, the nickel air tests seem low compared to others I have seen or read, should be closer to 10" inches I think.


Quick test coil specs (used the coil calc):
inner radius - 4.75"/120.65mm (9-1/2" coil)
wire - 18 awg/1.020 (blue pvc coated speaker wire)
Turns - 28 = 488mH

thanks for data
but my English not well and so i think better get video and put it here.
i just forgot the number of wire using for coil winding.i just now best result in 450mkH but res of coil i am forgot.
i make barracuda , please tell me about your transistors , just tell me for example Q1=mpsa13 .
regards
aha .... i get in ari testing with (250RIAL ,is Iranian coin ) in 19 to 21cm.
excuse for my English

[mohandes]

HI dear Tepco
what is your idea for this wave ?

waveform.JPG

[geoscash1]

Hey sinclairuser,

I did catch that about the 500 ohm pot, thank you for letting me know.... it was to late for an edit when I came back...

I'm gonna swap some parts around once I get that cap I have been waiting for to try some of the different ways and keep testing this board..

Mohandes, I have been testing with a few different surf pro coils (330 to 350mH) I have made for testing, they seem to work ok with the barracuda. Yesterday I wrapped a 9-1/2" (241.3mm) coil out of 18 awg (1.020mm) speaker wire I had laying around, used 28 turns for 488mH and it seems to work pretty well considering its just a loose bundle. I think once I refine it, it should be pretty good. I plan on making 10 to 12 different test coils of varying inductance for testing purposes from 280mH up to 585mH so I can better fine tune the board/coil combination with a specific coil inductance. Lots of variables to play with...

The speaker wire test coil I made yesterday ended up giving (in Air) 9" inches on a US 25¢ and 13" inches on an Australian 20 coin ($?), US 10¢ @ 8" inches, a US 1¢ penny @ 10" inches, a US 5¢ @ 7 inches, a ladies 18k gold ring at 8" inches, a beer bottle top at 12" inches and a crushed pespi can @ 30" inches. I'm happy with the results so far although I think once I find the right combo this barracuda will really kick some arse... I'd like to get the nickel and the gold ring (Silver&Gold) depths a little better so I'll keep fiddling with things to see if I can, the nickel air tests seem low compared to others I have seen or read, should be closer to 10" inches I think.


Quick test coil specs (used the coil calc):
inner radius - 4.75"/120.65mm (9-1/2" coil)
wire - 18 awg/1.020 (blue pvc coated speaker wire)
Turns - 28 = 488mH

[morganton]

disregard post

[mohandes]

hi geocash, the extra finetune delay pot is 500 ohms, not 500kohms.
if you like non motion detectors the extra transistor and two resistors, will achieve that, but while its still simple to do its not as easy with the newer boards.
and to be honest ive tested it both ways and if you like motion detectors i would not bother, the tip 127 instead of the irf fet is worth it, i think it has a better "attitude" with the tip127, the best tested components make a noticeable difference too.
the second one i built has only hi grade and millitary spec components, totally over the top, but i'm proud of it, i'm looking for a quality clear enclosure to finish it.
it is an excellent project, i recommend it at any level.

hi my friend
can you tell me about coil ( data of turn and ohm and radius) and depth detection for 10*10cm metal of this machine ?
regards.