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Treasure Hunting & Metal Detecting Forum Message Boards - Detector Hunter Whites Minelab Tesoro XP > Tech Talk > Modifications, Do It Yourself & Repairs (Moderators: Eugene52, xavier, GoldDigger1950) >

Wow! the best P.I. probe ever...... for nothing!

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xavier

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #40 on: April 08, 2010, 02:09:51 pm »

Used the ferite rod with a BFO as a probe and it worked very well I could detect a pin at 5cm with no problem.

Regards Xavier

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So many questions so little time

Engr Obaid

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #41 on: April 08, 2010, 03:05:42 pm »

In most of the detector circuits i have seen that ic( ICL7660) is used ,
Kindly tell me the specific reason why this ic is must in these circuits , because any operational amplifier ICs (NE5534, LF353 ) used in metal detectors circuits needs 5 to 9 volts , it can be easily provided by using any fix regulator ICs like 7805 or 7808,

Best Regard, Engr Obaid

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No detectors at the moment, 100 gpm suction dredge pump, 2" hand operated gold sucker, handmade bucket classifier, 9 inch cleanup sluice with v-matting

	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #42 on: May 06, 2010, 11:36:36 am »

I wouldnt say no one is interested Im interested and appreciate all information I can find on here that members post thanks to all!!!!
I am going to try and make this probe I will post in here when I finish. Foiled

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Gary's Pulse Induction

	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #43 on: May 24, 2010, 01:02:23 am »

	Quote:	Posted by Engr Obaid
In most of the detector circuits i have seen that ic( ICL7660) is used , Kindly tell me the specific reason why this ic is must in these circuits , because any operational amplifier ICs (NE5534, LF353 ) used in metal detectors circuits needs 5 to 9 volts , it can be easily provided by using any fix regulator ICs like 7805 or 7808,

Hi Engr,

The reason for the 7660 (or similar voltage converter) is because they create a negative voltage which is used by a 555 as a charge pump which can quadruple its input voltage. This is the high voltage pulse that is sent through the coil during the initial phase of detection. The 78L05 is used to create a stable voltage for the timing circuits while at the same time allowing the entire system to use only one power source.

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Engr Obaid

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #44 on: May 25, 2010, 12:08:31 pm »

Thanks for this information , actually i searched this IC specifications through net,
but my concept was not that much clear , i used this ic in one of my detector circuit ,
i found it very unstable , producing some sort whistle sound, as it supply power to amplifier ICs in the circuit , though proper wiring were done but no change in the stability

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Engr Obaid

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Gary's Pulse Induction

	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #45 on: May 25, 2010, 12:31:57 pm »

Hi Engr,

I would suggest you use 78L05 and 79L05 to drive your op-amps. Use the 7660 on a separate circuit isolated with capacitors to drive the coil.

Another thought: are you turning off the audio circuit when the induction pulse is sent? If not, that may be the source of your whistling sound.

-MM

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Engr Obaid

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #46 on: May 25, 2010, 01:26:20 pm »

Hi dear,
you means that the timing of switches (IC 4066 or some time FET use for switching) open & close might be same when power transistor have to send pulse to the coil & at the same time switch allow signal to the next stage amplifier stages. where in PI switch must be open when pulse is going to decay ,
i didnot noticed this situation, nice idea , i will try again.

Best Regards,

Engr Obaid

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Cornelius

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #47 on: May 25, 2010, 01:53:06 pm »

You guys are talking about a PI pinpointer Huh?

Why not go back to page one of this post and read what Paul found out about pinpointing . Cornelius

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Engr Obaid

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	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #48 on: May 25, 2010, 02:22:57 pm »

sir, actually in Reply #41 on: April 08, 2010, 04:05:42 PM ? i asked about the use of IC (ICL7660) in the MD circuits & we were discussing about issues of using this IC in the circuits.

Best Regards,

Engr Obaid

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Minelab Xterra 70

	Re: Wow! the best P.I. probe ever...... for nothing! « Reply #49 on: May 28, 2010, 11:15:36 am »

I find this thread interesting as I like to make stuff too. I have a Minelab Xterra 70. How do you use this probe in conjunction with your detector? Can anybody please explain this so I can make one too. Thanks,
Ray

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