2 boxxxx :)

[kt315]

hi Geo! does everyone know ALSO that brands do NOT use the foil and use GRAFITE ANYWHERE may be THIS WAS YOUR MISTAKE TO USE THE FOIL?

YOURS

[Geo]

Hi KT315.
I usually make mistakes. Maybe i can't tell us right because my English are not so good. Anyway i attach you a file that yesterday you attached here on this forum. It says about "shielded the foil". It don't say Shielded with Graphite ????
Any way the shield is shield. There are a lot of ways to do it. We look at the results.
But i said that at 2Box detectors there is not need for coil shielding. What to do the ground? It is not able to destroy the coils balance. Who is your opinion about it ?? I wait

[Shahab]

Hi

Thanks for your answers Gary & Nelson.

I use your calculator for turning the coil,Gary.

My result is:

Inductance15.0595 mH DC Resistance20.2491 Ohms Wire Gauge26 AWG Wire Diameter17 mils (1 mil = .001 in) Coil Length0.05 in Coil Inner Diameter12 in Coil Outer Diameter13.7 in Average Turn Diameter12.827 in Wire Length493.6388 feet Copper Weight0.3797 pounds Turns147 Levels49.98 Maximum Turns Per Level3 (Based on wire diameter)

But i say again that couldn't find 200n & 400n capacitors in my city.

I used 220n & 2*220n MKT/250V.

I think that must change the coil a litle.

What is your idea?

Thank you.

[kt315]

What to do the ground? It is not able to destroy the coils balance. Who is your opinion about it ?? I wait

strange people. IT IS DEEPER! do you see GEB in TM-808 schematic?! NO there is NOT! so why you are worry about ground does HERE?

[chemelec]

Hi

Thanks for your answers Gary & Nelson.

I use your calculator for turning the coil,Gary.

My result is:

Inductance15.0595 mH DC Resistance20.2491 Ohms Wire Gauge26 AWG Wire Diameter17 mils (1 mil = .001 in) Coil Length0.05 in Coil Inner Diameter12 in Coil Outer Diameter13.7 in Average Turn Diameter12.827 in Wire Length493.6388 feet Copper Weight0.3797 pounds Turns147 Levels49.98 Maximum Turns Per Level3 (Based on wire diameter)

But i say again that couldn't find 200n & 400n capacitors in my city.

I used 220n & 2*220n MKT/250V.

I think that must change the coil a litle.

What is your idea?

Thank you.

Firstly, I Would make the Coil Longer than .05 Inch.
Try .25 or even .5 inches.

Also, the Exact Inductance is Not Critical as the Caps are used to correct it for Resonance. Even a 10 mH Coil will work, it just means a different value cap to get resonance. That is what the *** Beside those values.

You DON'T Actually Want Those Capacitor Values.

What you Need to do is Start with a smaller vaue.
Example: Use a .22, Than Parallel a .1 with it, than Possibly a .005 and so on.
To try and get the coil in Resonance with the Frequency.

The Same applies for the other .2 Cap.
Start with a .1, Parallel a .05, Etc.

A Scope would be Very Useful for this.

[Shahab]

Thanks,Gary.

coil & capacitor make L-C resonance circuit,doesn't it?

[chemelec]

Thanks,Gary.

coil & capacitor make L-C resonance circuit,doesn't it?

YES

[nelson]

Tr locator

Hi Gary, today i had work on TR locator and i found some minor dubs that i like to comment to you.
On Schematics C13 and C14 looks like electrolitic capacitors, but on you board picture shows non electrolitics, which one is correct?
On schematic R10 and R11 i think both are R10 and can be any value btw. 47 and 100 ohms, i used 56 ohms on both.
C9 and C10 on schematic saids 220 uF electrolitics, but on parts list are C9= 220 and C10= 100, which one is correct?
C8 shows an electrolitic capacito but on the picture i can see a non electrolitic cap.
Please let me know the correct values.
Regards
Nelson

THANK TO ALL!!!!!!

HERE IS THE COMPLETED ARTICLE:
(My TEST SET-UP, PCB, SCHEMATIC AND PARTS OVERLAY.)

http://www3.telus.net/chemelec/Proje...-R-Locator.htm

Nothing better to do on my Birthday, but this for you all.

Hopefully No Errors on it.

[Shahab]

Hi Nelson.

No problem,you can look at the LM386 datasheet.C9 & C10 can be 220mf.

http://downloads.solarbotics.com/PDF/LM386.pdf

[chemelec]

Hi Gary, today i had work on TR locator and i found some minor dubs that i like to comment to you.
On Schematics C13 and C14 looks like electrolitic capacitors, but on you board picture shows non electrolitics, which one is correct?
On schematic R10 and R11 i think both are R10 and can be any value btw. 47 and 100 ohms, i used 56 ohms on both.
C9 and C10 on schematic saids 220 uF electrolitics, but on parts list are C9= 220 and C10= 100, which one is correct?
C8 shows an electrolitic capacito but on the picture i can see a non electrolitic cap.
Please let me know the correct values.
Regards
Nelson

For Head Phone Operation, C10 can be Almost anything.
I used a 100 uF, but becaues of the LOW Poer out, even a 47u is ok, or you want you can use the 220u.

C9 and C10, Either/Or 100 or 220uF
Not Critical.

C8 is a 1uF Tantalum. It is Polarized.
You could Substitute a 0.1uF Disk Cap, Non-Polarized if you want.

R11 Should be 10 Ohms.
SORRY, I Forgot to put it on the Parts List.

R10 Can be Any Value between 47 and 100 ohms, Just to Limit power to the Head Phones.

In the Origional Design, C2 was a 2.2 uf Polarized cap. But I believe a Non-Polarized one is better and I found the 1uF to work good.

Take care......Gary

[nelson]

TR locator

Ok Shaha and thanks for your info.
Gary, ok all is 100% clear and just one more thing, on schematic under R8 330K, there is a label marked R17 and i thing this was just a small error.
Finally, instead of 7812, can i omit it and just connect direct 6 volts to pin Nº 3 of VR1 (7812). This because i have a 1.2 Amps, 6 volt battery?
Regards
Nelson

For Head Phone Operation, C10 can be Almost anything.
I used a 100 uF, but becaues of the LOW Poer out, even a 47u is ok, or you want you can use the 220u.

C9 and C10, Either/Or 100 or 220uF
Not Critical.

C8 is a 1uF Tantalum. It is Polarized.
You could Substitute a 0.1uF Disk Cap, Non-Polarized if you want.

R11 Should be 10 Ohms.
SORRY, I Forgot to put it on the Parts List.

R10 Can be Any Value between 47 and 100 ohms, Just to Limit power to the Head Phones.

In the Origional Design, C2 was a 2.2 uf Polarized cap. But I believe a Non-Polarized one is better and I found the 1uF to work good.

Take care......Gary

[chemelec]

Ok Shaha and thanks for your info.
Gary, ok all is 100% clear and just one more thing, on schematic under R8 330K, there is a label marked R17 and i thing this was just a small error.
Finally, instead of 7812, can i omit it and just connect direct 6 volts to pin Nº 3 of VR1 (7812). This because i have a 1.2 Amps, 6 volt battery?
Regards
Nelson

YES, R17 Does not exist there. I will fix this up and some other stuff on it and I will Re-post it later today.

NO, You Can't just use ONE 6 Volt Battery.
It Requires 12 Volts there.

OR you Could Possibly Eliminate IC5, and use TWO 6 volt Batterys, Connected Properly to the Ground and the Plus (+) and Minus (-) Connections.

** But you will Not have any Voltage Regulation.
That May Cause Problems however I doubt it will.

[Geo]

What to do the ground? It is not able to destroy the coils balance. Who is your opinion about it ?? I wait

strange people. IT IS DEEPER! do you see GEB in TM-808 schematic?! NO there is NOT! so why you are worry about ground does HERE?

You don't understand me or i can not to give you the right words to understand me. It is the same, so let it............
Bye

[chemelec]

Hi All, I have Now updated the Schematic on my website.
You Might Need to Hit "Refresh" to get it correctly.

http://www3.telus.net/chemelec/Proje...-R-Locator.htm

Hopefully this should help out some of you Better.

Gary

[kt315]

You don't understand me or i can not to give you the right words to understand me. It is the same, so let it............
Bye

sorry, may be I bad interpreted your words. if you will not use shields the coil untuning will go more than if in case you use the shields. but big problem would be not because a finish tuning must be done in a field as I had wrote above. you write 'balance' but I think this is not right here, because here is not IB principle similar to ordinary metaldetector with DD or planar coils.

yours