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Post by Gary Lecomte on Dec 5, 2004 9:00:19 GMT -8
Comments from anyone Appreciated.
Take Care.......Gary
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Post by HiiQ on Dec 6, 2004 9:49:42 GMT -8
I will try to use this schematic to make a high power detector. and eventually upgrade it to something like the GEM-300. ,hope it works.
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Post by Gary Lecomte on Feb 15, 2005 6:59:25 GMT -8
Once you build it and see how sensitive it is, I Doubt you will need to make it more Powerful.
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Post by charlesmanning on Jun 13, 2005 18:13:20 GMT -8
Hi Gary Thanx for providing your PI metal detector design. I have built a few before and really liked them. I have an on-again/off-again PI project that is intended to be entirely (well almost!) digital. The basic idea is as follows: 1) Microcontroller times the output pulse 2) The kickback pulse is squared up and timed by the microcontroller. When a metallic item is present, the pulse lasts longer. 3) The microcontroller monitors the pulse lengths and generates tones accordingly. A note on your "flat coil". I guess this is inspired by what were called "spider coils". These were often used in crystal sets and still are. They provide exceptional Q, relative to a solenoid coil. The way you have wound the coil by looping back presents some problems. Those loop-backs are essentially reverse direction inductors which will likely cancel out some of the induction of the main coil. Is that what you really want to achieve? Instead it might be worth trying the more traditional "spider coil" winding methods. An easy one is to use a former with an odd number of slots and then go in/out/in/out... between them. For an example, look at www.oldradioworld.de/gollum/spider.htmIt isn't that odd to steal ideas from crystal radios. Amplified radios can get away with very poor inductors. Crystal radio inductors have to be close to perfect. Having very good inductors helps PI detectors too! I might not go as far as using Litz wire on a PI though! Have fun. -- CHarles
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Post by Gary Lecomte on Jun 19, 2005 6:31:04 GMT -8
I am Not sure I understand What you mean.
There are NO Reverse Loops on my Coils. The Coil is a Continuous Spiral, all in one direction.
Yes that Spider Coil will also work, and if you look at my project carefully, you will see a Simular design that I made for testing purposes. Although I prefer my flat coils over that one.
Gary
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Post by charlesmanning on Jun 19, 2005 18:53:56 GMT -8
Aah yes! Sorry...
It looked to me like the coil was being looped back, but I see now that it isn't.
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Post by WRKQ on Aug 18, 2005 6:35:27 GMT -8
One more question: On the photo of your unit's front panel there is a LED shown. Where it should be connected?
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Post by Gary Lecomte on Aug 20, 2005 4:37:44 GMT -8
One more question: On the photo of your unit's front panel there is a LED shown. Where it should be connected? On My Unit, That is Just an On/Off Indicator. Gary
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Post by Jochen on Sept 4, 2005 18:03:53 GMT -8
I might not go as far as using Litz wire on a PI though!
Have fun. -- CHarles
I made the chemelec-PI and lots off different coils. I used these spider-coils for mechanical + capacity-reasons. I also used solid wire and rf-litze with internal 30 or 40 conductors and I could not find a difference in detecting-range. What I found was that the solid-wired coils where finally heavier than the coils made from rf-litze after everything was properly epoxyied, which was important to me because one is swinging them on a long handle and I had tennis-arm that time.
regards, Jochen
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Post by Jochen on Sept 4, 2005 18:05:49 GMT -8
I might not go as far as using Litz wire on a PI though!
Have fun. -- CHarles
I made the chemelec-PI and lots off different coils. I used these spider-coils for mechanical + capacity-reasons. I also used solid wire and rf-litze with internal 30 or 40 conductors and I could not find a difference in detecting-range. What I found was that the solid-wired coils where finally heavier than the coils made from rf-litze after everything was properly epoxyied, which was important to me because one is swinging them on a long handle and I had tennis-arm that time.
regards, Jochen
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Post by joe on Nov 1, 2005 20:11:40 GMT -8
Hello sir, Is there a way to put some additional parts inside the P.I so that there will be additional LED indicator on the panel and for me to know that i have detected a non ferrous from a ordinary metal or magnetic metal under the ground?can u share the additional circuit that i should add up to the P.I circuit you design? Joe
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Post by Gary Lecomte on Nov 3, 2005 6:01:26 GMT -8
Sorry Joe, There is no way to do this.
Pulse Induction detectors are typically Non-Discriminating.
Gary
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Post by engsannan on Aug 23, 2007 11:51:14 GMT -8
hi i am desinging metal detecter to detect metal in air that is search human; not in ground. what would u advise for the coil if i used VLF metal detecter approach
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Post by Deleted on Mar 4, 2011 9:09:25 GMT -8
hi there I could not find where you give the pcb?
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Post by Gary Lecomte on Mar 4, 2011 14:23:13 GMT -8
hi there I could not find where you give the pcb? As it SAYS in my detector Article, "ONLY FROM ME"! It is included in the Basic Kit of parts, Which you need to purchase to get it. SORRY, but I have had too many persons build it using poor Quality parts or making Poor PCB's, than expecting me to FIX IT. It became too Time Consuming and too much of a problem for me. This Way, I Know the Board and PCB are good. IF you want the Parts and Price List, EMAIL ME.
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