New Homebrew Metal Detector

[zisme]

what capacitor have you installed, because i have a problem with 270 MHz.
hmmm pins are good i've checked c/b/a 1/1/0 please help my email [email protected]

Which capacitor? 270 mHz.???? Please explain.

Mike :confused:

what capacitor have you installed, because i have a problem with 270 MHz.
hmmm pins are good i've checked c/b/a 1/1/0 please help my email [email protected]

[omega]

Hallo,

how good is this detector when you compare it whit another projects like Hammerhead or Gary´s? I wanna built it but i wanna now if this detector is good or not.

Thanks,

omega

[ivconic]

Not yet...


Not yet...
my e-mail is [email protected]

anyway thanks a lot for good will..
regards

[Geo]

:confused:




Do you have that manual scanned? If file is not bigger than a few mbytes, than o.k. send
it.
Best regards to you Geo

Hi Ivconic. I sent it to you via email. I have some problems with emails so did you received the file with the manual?
Regards

[Seeker]

I use ZTX415 Uc-200V , Ct-2nF for laser diode, pulse ~ 20ns, but this can be used for coil.I can't understand why everybody use analog schematic for time measurement?You can optimize method , if use counter to measure time for fadind of coil voltage.

[Seeker]

I have this transistor in sot-23,made by ZETEX, Ic-50A, Uc-150V, I think this is better for your detector, but you mast change schematic.I have made power supply for laser diode with this transistor.This is very good for UWB generator.You mast use HiVolt supply.

[zisme]

Hi Zisme,
I think it is better to use avalanche transistor, then mosfet .

Best regards

Have you tried any avalanche transistors? Do you have any part numbers that work?

What do you think about the ZTX413 ? It's in a TO-92 case and is good for 200 Ma. continous current with a 50 amp. peak pulse rating. See data sheet here: http://rocky.digikey.com/WebLib/Zete...ata/ZTX413.pdf

If this works, it would eliminate a lot of space used by the TO-220 FET.

Mike

[Seeker]

Hi Zisme,
I think it is better to use avalanche transistor, then mosfet .

Best regards

[ivconic]

ivconic is now SEE-NILE!!!


Ha,ha,ha,ha......but of course! Stupid me! Yesterday i checked your answer
and reply "on the fly" here, without much of brains, i guess.
You are right now! Thank you being good help.
It is correct now. I am going to fix some coils here....


best regards

[zisme]

:confused:
Now i am even more confused...But first thanks for replying me.If i am to persistant and buging you, it's quite alright to tell me. Due to real wish to
make that coil i just have to bug you more...
Your latest post confused me more. According to your measures it will take approx. 69 turns to reach 9.5 inches, with the .043in wire! Not 27.
I 've been visited your site and no changes there,no updates yet.
Anyway,inner former is now right and known, so i am gonna start all over again to wind that coil.It is so interesting to me to try to gain your results.
If inner is 6.5 inches and outer is 9.5, for windings 3 inches are left.Divide 3
inches with .043 and you'll get some 69 turns.O.K. we do not need to be so
neat, let's say from 65 to 70 turns !!!???
It is too much i guess!
O.K. i will wait your opinion on that.
best regards

9.5 minus 6.5 equals 3 is correct, but you forgot to divide by 2 to get the radius of windings which is 1.5. Then dividing 1.5 by .043 gives you 34.88 turns if wound absolutely tight. However, my windings are not very perfect, so it came out to 27 turns. Given the error in measuring the diameter of the wire and consistancy of the enamaled wire, I say that's probably pretty close.

The update to the website was a new picture of the coil with the correct dimentions on it.

Thanks again and never think you are bugging me.

Glad to help,

Mike

[ivconic]

Even more confused !!??

:confused:
Now i am even more confused...But first thanks for replying me.If i am to persistant and buging you, it's quite alright to tell me. Due to real wish to
make that coil i just have to bug you more...
Your latest post confused me more. According to your measures it will take approx. 69 turns to reach 9.5 inches, with the .043in wire! Not 27.
I 've been visited your site and no changes there,no updates yet.
Anyway,inner former is now right and known, so i am gonna start all over again to wind that coil.It is so interesting to me to try to gain your results.
If inner is 6.5 inches and outer is 9.5, for windings 3 inches are left.Divide 3
inches with .043 and you'll get some 69 turns.O.K. we do not need to be so
neat, let's say from 65 to 70 turns !!!???
It is too much i guess!
O.K. i will wait your opinion on that.
best regards

[zisme]

[quote=ivconic]:confused:
Hi Zisme !
It appears that some harmonic became stronger than main pulse.Why? Well,i guess,i put
some of the filtering component bad!I had to check them all over again, some of them
not new, i used a lot of scrap components( i have tons of them)...
You are right about C3.
Also crystal is not hard to obtain.I just used first nearby i found.
About wire...i might be wrong. It's so hard for me to manage with all those standards..
Is it awg, swg or bwg standard you are talking about? Let's measure in mm's for a while.

Wire #20 could be 0,81mm(awg) or 0,89mm(bwg) or 0,92mm(swg).....
The former is 5.75 in as you said. It means 14,605cm in my language and mind (since i am
european and it's so hard for me to think in inches).
27 turns of wire on 14,605cm former should give us:
- 16,792 cm or 6,61 inches spiral coil diamm. respecting AWG or
- 17,008 cm or 6,71 inches spiral coil diamm. respecting BWG or
- 17,089 cm or 6,72 inches spiral coil diamm. respecting SWG standard.
Anyway, it ends on some bellow 7 inches, but not on 9,5 inches !!!???
You said 27 turns, but it will take much more to reach 9,5 inches with #20 wire by any
standard.Or maybe you started with 27 turns and continued while got some good results?
Anyway,if it's possible,(it would be so help for me), to measure wire you used in mm's
and reply here or detailed explain your coil, since results you posted here are very good!
The very best regards to you, and thank's in advance!

.................................................. .......

I must be getting SEE-NILE!!! I took the coil apart and measured the winding again, and the inside diameter is 6.5 inches! I had been measuring my coil winder inner form, but I forgot that I did remove some of the inner turns because I ended up with too much inductance. Sorry, sorry, sorry....about that. I have corrected the measurements on the website. Thanks to you for being persistant about it. I measured the diameter of the wire with my dial caliper which came out to .043 inch.

Hope this helps with your coils and again, thanks for finding this,

Mike

[ivconic]

Always forgot....


One more thing....
Your results:
U.S. penny: 12 to 15 inches......30,48cm to 38,1cm
U.S. nickel: 9.5 to 10 inches....24,13cm to 25,4cm
Car.............................121,92cm to 152,4cm
I can tell you that those results on coins are excellent, with such small coil!
But on car, result is average....
I would like to gain such results on coins, with my home-made detector, and
such a small coil diamm.
THE REAL THING, WHEN PROSPECTING COINS, IS TO USE AS SMALLER COIL AS POSSIBLE,
DUE TO SPEND LESS TIME ON PINPOINTING,ALSO AVOID POSSIBILITY TO DAMAGE ITEM
WHEN DIGGING....
My Delta PUlse, with 42cm coil is detecting coins from 20 to 27cm, but car
(Wolksvagen Golf II) it can detect over the 200 cm.....
With 75cm coil, very poor on coins(20cm...27cm) but on car over the 300cm !
.................................................. ............
Now back to your post....
"Also, another difference between your detector and mine is the current draw. My
detector draws much more current than yours which means it's putting more current
into the coil. Of course, mine is running at 109 Hz. too."
I guess, it should be oposite. Higher freq. - draws much more current!
Also thick wire in coil...But, thick wire and lower freq. are suitable when prospecting
big items at high depths.I want to prospect coins and small items at lower depths up to
45-60cm , no more.That's why i am experimenting so much with PI's...Also i have a few
of IB's(some of them very good), but PI's are my favorites!
"You said you left out the voltage regulator, what is your input voltage? If you drop
below 12 volts, the range starts to drop off quickly"
Voltage is 13,6 volts. Straight from accu. 6 Ah.. I left out v.reg. and add 11000 microF
capacitor,cose wanted to use heavy duty accu, which sometimes can vary from 13.xx to
12.xx volts and i guess than in some conditions, that low drop can cause some problems on
the field.
Also it is much safer now to experiment with higher voltages, up to 18 volts...only have
to "isolate" IC's fedding from driving voltage, by using some small reg. in that rail. But
it will open this project for much more improvements and lead us to whole new project.
I do respect this project of yours, cose it is small,simple and very usable! I am planing
to keep it as it is,pack in some small box and use it in places where bigger machines
not suitable for handling( holes,caves,pipes,etc....).
But also, i can aprove your case, where, you put another type of accu's, and , of course
it is much better to use v.reg....I can agree on that 100%...
"...Again, thanks for the feedback and good luck..."
No, friend ! THANK YOU, for sharing with us, here, your schematic and project,hints...
Also showing a good will to help!
best regards

[ivconic]

inches....

:confused:
Hi Zisme !
It appears that some harmonic became stronger than main pulse.Why? Well,i guess,i put
some of the filtering component bad!I had to check them all over again, some of them
not new, i used a lot of scrap components( i have tons of them)...
You are right about C3.
Also crystal is not hard to obtain.I just used first nearby i found.
About wire...i might be wrong. It's so hard for me to manage with all those standards..
Is it awg, swg or bwg standard you are talking about? Let's measure in mm's for a while.

Wire #20 could be 0,81mm(awg) or 0,89mm(bwg) or 0,92mm(swg).....
The former is 5.75 in as you said. It means 14,605cm in my language and mind (since i am
european and it's so hard for me to think in inches).
27 turns of wire on 14,605cm former should give us:
- 16,792 cm or 6,61 inches spiral coil diamm. respecting AWG or
- 17,008 cm or 6,71 inches spiral coil diamm. respecting BWG or
- 17,089 cm or 6,72 inches spiral coil diamm. respecting SWG standard.
Anyway, it ends on some bellow 7 inches, but not on 9,5 inches !!!???
You said 27 turns, but it will take much more to reach 9,5 inches with #20 wire by any
standard.Or maybe you started with 27 turns and continued while got some good results?
Anyway,if it's possible,(it would be so help for me), to measure wire you used in mm's
and reply here or detailed explain your coil, since results you posted here are very good!
The very best regards to you, and thank's in advance!

.................................................. .......

Geo...
"Hi Ivconic. If you still work with D.P then i can send you the manual. I found it."
Yes Geo. I made another DP and it is working much better than first one.I am so glad.
It shows that Delta Pulse (or XR 71, whatever) is very good,nice and usefull detector.
The second one i made is so good that reaches PulseStar II performances! So Pulse Star II
is "history" now! I am gonna sell it as soon as possible.For those money i can make over the
15 Delta Pulses more!Why keeping "dead" capital at home !?
Do you have that manual scanned? If file is not bigger than a few mbytes, than o.k. send
it.
Best regards to you Geo