Universal PI Micro

[Atul Asthana]

Discrimination

Bugwhiskers,
Thanks for the reply.
Can I request you to post decay diagrams and timings for various targets, which I could utilise in understanding the discrimination process and setting sampling delays.
Thanks once again.

[bugwhiskers]

Hi Atul Asthana,

It's not possible to give you absolute locations in terms of microseconds out from TX off to take your samples due to the spread of coils, pre-amp types and feedback caps on the pre-amp.

It's all a matter of adjusting the locations and widths of the two samples to get the maximum signal difference between targets of differing conductivity.
The best place to put the first sample is where the decay is more horizontal than vertical, just past the knee of the curve.

regards
bugwhikers

[1843]

UPIM Principle

Hi Atul Asthana,
Its principle is here:



Regards!

[Atul Asthana]

Discrimination : Decay diagrams

Thanks 1843.
That has helped me understand the discrimination. I can see where all I need to sample.
However,
What do the numbers indicate? are they relative time delay values? [5.85, 8.3, 34.1]
And what is the significance of the T[0....5]?

[bugwhiskers]

Hi Atul Asthana & 1843,

Thanks for that pic, it makes it a lot easier for people to understand the underlying principle.

You can clearly see that the better the conductor the flatter the curve.

The "T's" relate to the timings of the samples but it will only apply to their coil/preamp configuration, just experiment to find the sweet spot.



regards
bugwhiskers

[1843]

Thanks 1843.
That has helped me understand the discrimination. I can see where all I need to sample.
However,
What do the numbers indicate? are they relative time delay values? [5.85, 8.3, 34.1]
And what is the significance of the T[0....5]?

You need 2 sample, depends on your coil. If your coil is fast enough like the diagram you can use T5 and T4 (both in microsecond). The diagram timing is the best positions for proper DISC and keep in mind that the samples width should be 1 to 5us.

If your DISC doesn't work OK with this timing, then it means that your opAmps gain is not set properly. You should try to get this timing and then set the samples gain.

Regards,
1843

[Atul Asthana]

Discrimination : Decay diagrams and settings

Thanks, that helps.
I guess, carrying out this comparison in software should be still better. I hope the ATMega8 design will be available in the near future.

[Unregistered]

Advanced Circuitry

Every one here seems to be a nut case mumbling to themselves, just like a cpu talking to ram without any proper output, with their clone schematics, try to get to the front end circuitry you fellows. Just changing the display with graphical one and cloning the hardware wil not help you fellows, since year 2000 i am seeing this site, and no improvement, many 2nd grade manufacturers in India has a PI detector which can detect a cannon ball 5 feet away in air, you fellows dont even come to this limit, and you cant come to the speck of 20 feet detectors....

[pike]

lazy scope owners

People having test instruments etc should experiment with low noise designs, and using optos for signal transmission etc etc.... the noise feedbacks from ground etc etc these fellows are lazy and very lazy.

Every one here seems to be a nut case mumbling to themselves, just like a cpu talking to ram without any proper output, with their clone schematics, try to get to the front end circuitry you fellows. Just changing the display with graphical one and cloning the hardware wil not help you fellows, since year 2000 i am seeing this site, and no improvement, many 2nd grade manufacturers in India has a PI detector which can detect a cannon ball 5 feet away in air, you fellows dont even come to this limit, and you cant come to the speck of 20 feet detectors....

[Atul Asthana]

Every one here seems to be a nut case mumbling to themselves,

Every one here seems to be a nut case mumbling to themselves, just like a cpu talking to ram without any proper output, with their clone schematics, try to get to the front end circuitry you fellows. Just changing the display with graphical one and cloning the hardware wil not help you fellows, since year 2000 i am seeing this site, and no improvement, many 2nd grade manufacturers in India has a PI detector which can detect a cannon ball 5 feet away in air, you fellows dont even come to this limit, and you cant come to the speck of 20 feet detectors....

Excellent information from Unregistered. I am sure s/he will like to enlighten us with a little glimpse of the technology used by 2nd grade manufacturers instead of complaining about no improvement.

Are you there???

[bugwhiskers]

Making a PI that will see target at a distance is one of the easier tasks. All that is required is a large coil, lots of current and lots of amplification.
Making a detector that can eliminate the ground signal that in some instances can be thousands of times stronger than the target and being able to discriminate is the real challenge.

regards
bugwhiskers

[gef12]

What I think bugwiskers is trying to say fellows is that trying to find gram size gold nuggets in heavily mineralized soils / grounds is the real challenge and he is doing well. Who needs to find cannon balls 5 feet in the ground ..you have to put in the hard yards and then dig for it ... give me the gold any day.
cheers
gef

[Atul Asthana]

AVR design? Is any one working on it?

Is any one working on a ATMega design for this PI detector?

[rajesh]

t/r

hi atul im form indor mp mai bana raha hu gary chemelec ka t/r locator 10 peas our ke pahle maine gary ka pulses 1 banaya tha this good working 1 meter for big metal mera mobile no hai 9893588660....

[Atul Asthana]

Rajesh ji,
Check your private message.