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Offline fff
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« Reply #10 on: July 10, 2011, 11:51:33 pm »
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30msec delay is optimal for search in ground.For small objects  use small search coil-15 sm diameter  .

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« Reply #11 on: July 11, 2011, 08:29:10 am »
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Quote:Posted by fff
30msec delay is optimal for search in ground.For small objects  use small search coil-15 sm diameter  .
 Thank you for your response fff. I asked because each PI has the disadvantage that detect tiny gold (chains, broken rings ...). I know the rule for small items to a smaller coil. The best combination of Dual Field coils 150mm * 300mm. With Dual Field coils maintains a sensitivity to small objects.

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« Reply #12 on: July 22, 2011, 06:22:26 pm »
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just modify the transmitter power,frequency,delay,sampling, for big and small targets. selector switch is good idea.

ram,

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« Reply #13 on: July 23, 2011, 11:27:14 am »
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Hi ram. I totally agree with you but so much modification would lead to a completely different PI detectors. SBG - PI is an interesting project but unfortunately it is anticipated the constructor as a detector for deep search (great items at great depths), delay in the range of 33uS to 150uS.  For gold chains and stuff similar delay should be <10uS (or8, or6 ...) to 60uS and of course a small coil <20cm. For instance some of the PI detectors are good for coins: Barracuda pulse delay = begin at 22uS to 60uS, Deepers8 pulse delay 10uS-60uS...

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« Reply #14 on: July 24, 2011, 01:50:28 pm »
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Quote:Posted by dr.jare
Hi ram. I totally agree with you but so much modification would lead to a completely different PI detectors. SBG - PI is an interesting project but unfortunately it is anticipated the constructor as a detector for deep search (great items at great depths), delay in the range of 33uS to 150uS.  For gold chains and stuff similar delay should be <10uS (or8, or6 ...) to 60uS and of course a small coil <20cm. For instance some of the PI detectors are good for coins: Barracuda pulse delay = begin at 22uS to 60uS, Deepers8 pulse delay 10uS-60uS...


yup, but we have to make experiments based on different kinds of pi designs for more accurate and powerful pi and to be posted in this forum for diy projects. please don't stick on one design, keep on modification designs. don't let your imaginations shutdown. wizards on this forum were ready to help based on their higher knowledge on pi md mods.

ram,

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« Reply #15 on: July 25, 2011, 12:05:31 am »
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Delay in the range of 10uS to 72uS if C9=3.3nf and R23=22k.R4=330-470k.Input gain reduced.

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« Reply #16 on: July 25, 2011, 12:53:23 pm »
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Quote:Posted by ram
yup, but we have to make experiments based on different kinds of pi designs for more accurate and powerful pi and to be posted in this forum for diy projects. please don't stick on one design, keep on modification designs. don't let your imaginations shutdown. wizards on this forum were ready to help based on their higher knowledge on pi md mods.

ram,
   Hi ram. For PI detectors can not be anything revolutionary to invent because the prevailing laws of physics. For example, how many coil - so detection for coins... fff invented something that so far I have not seen, creates a digital signal, delay is not regulated by potentiometer as in most other PI detectors... Best regards.

Posted on: July 25, 2011, 12:49:18 PM
Quote:Posted by fff
Delay in the range of 10uS to 72uS if C9=3.3nf and R23=22k.R4=330-470k.Input gain reduced.
Hi fff. Thank you for your response. PI detectors have the problem of poor detection of small nonferrous objects, see the example on this video: 

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. That's why I asked for a lower delay, but you say that the input gain reduced. Best regards.

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« Reply #17 on: July 26, 2011, 12:11:59 am »
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Changes for old schematic /Bulgarian pi/, not for Sbg-pi.For SBG-PI-exchange quartz frequency in 100 kHz or exchange oscillator with frequency changed RC oscillator 20-120 kHz. 

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« Reply #18 on: July 26, 2011, 02:17:22 pm »
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fff thanks for the reply. Now I understand: quartz from 32kHz replaced with quartz from 100kHz. On the PCB can add more of quartz with a choice of several different frequencies (with switch)... Best regards.

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« Reply #19 on: July 27, 2011, 09:39:29 am »
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Hello, Is anyone made this scheme?Are you  Work?

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