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Will run the test tomorrow and let you know.
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Using a common ungalvanized straight iron 8D nail and the newly wound bigfoot spider coil, the nail presented end on to the coil center always indicated as 'Iron' with either end. Presented perpendicular to the 'blade' field of the Bigfoot spider it always indicated as 'Iron' even at the lowest signal levels. Presented parallel to the 'blade' search field of the Bigfoot detection at 4 1/2" showed as the left hand default scale of the VDI for Aluminum/Gold but at 3 1/2' it was pretty solidly indicating as 'Iron' because the signal strength came up. The behavior of the discrimination with the nail perpendicular to the search blade is very interesting to me. It may be another useful tool to use in discrimination and I think this is the coil type I'll likely use a lot.
Regards,
DanComment
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Dan, thanks for the information.Comment
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baum7154, аs the trials progress "dual amplifier"? Draw the last option please improvements "chance." I want to upgrade your MD.
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Hi.chance detector work well?
some body say have error and not prefect?Comment
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I will gladly update the schematic with the latest changes. I'm celebrating a belated Christmas with my family today and tomorrow but after that will update and post the changes.
DanComment
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hi all
I can discrination with a 2m coil?
thank youComment
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Merry Christmas to you and to all!Comment
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____________________________Originally posted by mohandes View Post
If you have read completely through this thread I have 120 detailed posts on the results of using/modifying/testing CHANCE PI over the last 3+ years. The earliest release of the CHANCE PI detector was unfortunately not successful and most of the people discarded it and never came back. As a result they spread the word that CHANCE PI is not worth the time. However, those that held on for the later software releases were finally rewarded with Software Version 1.2.1 and it is the best and only software version to use and pursue development with in my opinion because it totally changed the detector from the prior versions.
In the time spent with CHANCE PI it became obvious to me that the detector first required a very fast coil in order to be able to detect small gold, and small gold is my purpose with this detector. Toward that end I settled on the coil type detailed in the CHANCE PI COIL thread where I have 69 detailed posts, many with construction photos. This coil has allowed me to reach the limit of CHANCE PI's 8 us minimum sample delay capability. Note the original CHANCE PI coil by it's designer was far too much inductance for small gold and is unshielded and was never intended to allow operation below about 20us. This limitation in the author's coil while OK for coins, led to the perception that CHANCE PI was not worth the time. With the CHANCE PI Coil it is worth the time in my opinion.
After building a successful 335 uh 8" round fast coil and looking at the coil decay (7us) vs the single stage receive amplifier output in the original CHANCE PI design it became apparent that the amplifier needed an upgrade because it was going into saturation adding more delay to the signal presented to the A/D. After unsuccessfully searching around for a 2 stage amp design compatible with CHANCE PI it was decided to design my own. The goal was to make a 2 stage amp on a sub board that plugged directly into the original single stage amp socket with no modification of the original CHANCE board other than the removal of a few components from the original board. The new amp does not saturate, even with a 31% increase in gain over the original design.
So to answer your questions, 'Yes' CHANCE PI works well for me and 'Yes' it is not perfect. No detector is perfect, even the Minelabs PI detectors have discrimination difficulties at low signal levels, and so does CHANCE PI. But I would rather have discrimination at signal levels above 5 to 6 units of receive signal strength than to have no discrimination at all. For the weak signals below that threshold I am happy to dig the weaker targets, just like all the analog detector users must do.
For me the choice for CHANCE PI is driven by the sophisticated micro controlled, software defined, multi-pulse design, with potential for future software upgrades, a menu driven detector, 8us delay capability, discrimination at mid to high signal levels, with signal barrier(quiet threshold), iron masking, guard interval (sample delay),volume raise on detection settings, minimum operating voltage settings, zeroing, etc. all at my fingertips from the menu. As a result this is a detector that has much flexibility in it's setup by the user and it takes time to understand it and what info it is giving you. The audio output gives discrimination for gold/aluminum as a low tone, Silver/Copper as a very high pitched tone and Iron as a high tone. Coupled with Discrimination and Signal Strength indications from its VDI the user can deduce whether a target is worth digging if the signal is over 6 units of strength. The lack of an explicit user manual explaining this has caused much confusion in the detectors operation and that also has led to some frustration for early builders.
I am still pursuing performance enhancement of this detector especially for small gold depth and for user convenience. It would be nice to get 30 cm of depth on a 1/2 gram nugget but that is still elusive. I am also pursuing other fast coil shapes/fields for use with this and other detectors.
If you choose to build CHANCE PI, I welcome your input and collaboration. I could use another builder's efforts, test results, discussion, and commitment to this detector. Those with a working CHANCE PI to experiment with are the best to collaborate with on it's improvement.
I hope these answers are sufficient.
Regards,
DanComment
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Good post DanComment
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Hi Dan
I am still interested in building the Chance PI or something similar of my own design. I have read your many posts and appreciate the knowledge that you have shared.
I am still trying to understand more about the Chance PI. The attached file is translated from the chart on the Russian website. I have tried to apply my understanding of your posts to the chart. Maybe you can tell me if I am misinterpreting what is being charted?
Can you help me identify where the data connections are made in the circuit diagram? Or if derived from the software do you have some understanding of how it is derived?And what units/values they represent?
Thank you,
Chet
Chance PI translated Russian chart.pdfComment
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-=-----------------------------------Originally posted by Chet View Post
Your chart is generally correct as to where the targets will appear on the VDI. Target geometry such as iron rings or bottle caps will be outliers in the plan especially at low signal levels and will show up at the left hand default location of the VDI until signal strength increases. If you take a look at the close up photo of the front panel of my detector you will see the positions of where the specific metals are presented by the decals on the perimeter of the VDI. These markings are made without any 'Mask' in play.
Data connections for programming are via the 10 pin 'X2' connector. I have no knowledge as to how the software is written but Silver Dollar has a copy of 60 pages of some version of the software. If it is not Version 1.2.1 it will be of less value to us.
Regards,
DanComment
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