Chance Pi problem....¿¿¿????

[der_fisherman]

Ditto
This forum must stay the way it is, after all thats what draws us here like a magnet attracting metal, A good example of that was and still is the tgsl which avconics started off which has gone from head to foot then onsite working as designed In education and development, contributed by some very clever engineers who dont ask for anything in return apart from new Ideas from other like minded people looking from a different angle.
Regards
Dave

Did you mean Ivconic?

regards

Andy

[satdaveuk]

Did you mean Ivconic?

regards

Andy

yes I did sorry for spelling your name wrong Ivconic , its my old age creeping up on me
Der fisherman Is there anyway that page can be edited? it looks bad me spelling his name wrong, and after looking at it again my spelling throughout was crap considering I am english, better me mention it before anyone else does
Regards

[der_fisherman]

yes I did sorry for spelling your name wrong Ivconic , its my old age creeping up on me
Der fisherman Is there anyway that page can be edited? it looks bad me spelling his name wrong, and after looking at it again my spelling throughout was crap considering I am english, better me mention it before anyone else does
Regards

I was simply wondering if we had a new poster or not!

I wasn't trying to criticize, my spelling could be improved as well (we are not alone here!!)

The spell checker appears to be US only and it does not correct names (normal).

regards

Andy

[mschmahl]

Thank you Tepco for your wonderful declaration.

Orginally Posted by Tepco
It is possible in this software version, at least to some degree. Old versions of Chance had fixed, long sampling time (17uS), not suitable for small conductive targets. In this version "guard interval", that is, minimum delay for at least some samples (detector uses 28 in this version) can be adjusted (10-99, 30 is default for original coil, not in uS), the best and most useful feature of new software. Using faster coil whit proper dumping R (R13), preferably flat spiral design, and reducing guard time to minimum will do the trick. If you go below minimum time coil can provide, detector will just "die out" and stop responding to metal completely. Fast enough coil and minimal guard time is what you need, no more gold (or silver) "blindness" and still good behavior in bad ground. Same way, detector now can be adapted to larger coils or frames. Original coil is too heavy, complicated to build, not so fast, it is only 8", probably the weakest point in this design. Playing whit different coils can reduce sensitivity, change ground behavior, shift VDI/ Iron mask position (don't count on it too much anyway), but at least now it is possible.

The target of my interest are Silver coins (see below).
I have found someone on a trashy field with my minelab explorer xs. They were still just to locate (25-30 cm in the ground). I think there are other coins but deeper. So i will build a bigger coil for the chance (bigger than the original coil). I have played with different coil´s for the chance (different wire, different diameter, flat wound spiralcoil, mono coil). I had between 400-650 uH.
Is this to high?

All my experiments with coil´s were with Version 1.1.1. This was a big mistake
Now i have Version 1.2.1.

Thank´s a lot to share your knowledge.

[mickstv]

Ground nioise

Just wondering if anyone has had any luck with this detector. My in air tests show good results using my Minelab SD2200 mono coil. In air it can pickup a 0.6 gram nugget at about 3 inches. But as soon as I try to test on ground the detector is constantly picking up false signals every few feet, with nothing found. Also the soil is only slightly mineralised. I've got the Barrier up up to it's highest level but it's no better.

Any help would be great.



Mick

[WM6]

Just wondering if anyone has had any luck with this detector. My in air tests show good results using my Minelab SD2200 mono coil. In air it can pickup a 0.6 gram nugget at about 3 inches. But as soon as I try to test on ground the detector is constantly picking up false signals every few feet, with nothing found. Also the soil is only slightly mineralised. I've got the Barrier up up to it's highest level but it's no better.

Any help would be great.

Mick

Which hex code version did you use?

[mickstv]

Which hex code version did you use?

Hi WM6, I used ver 1.2.1 and also tried 1.0.1.

[Tepco]

[quote=mschmahl;134548]

The target of my interest are Silver coins (see below).
I have found someone on a trashy field with my minelab explorer xs. They were still just to locate (25-30 cm in the ground). I think there are other coins but deeper. So i will build a bigger coil for the chance (bigger than the original coil). I have played with different coil´s for the chance (different wire, different diameter, flat wound spiralcoil, mono coil). I had between 400-650 uH.
Is this to high?

All my experiments with coil´s were with Version 1.1.1. This was a big mistake
Now i have Version 1.2.1.
quote]

I don't have anything similar for comparison at hand, but target like this will be relatively "slow" one, just due to it's size, no matter silver or alloy, and detector will pick it easily. Just make larger coil (28 or even bigger), but still keep some "fast" design. Unlike early version, this software seems to tolerate very wide range of coils (i tried some way off specs). When you know target type it is easy to optimize coil and detector settings. Also will be interesting to see behavior in real soil (there are some complains about it already). Inductance range 200-600uH worked just well in air tests, coils made for different detectors, different sizes etc, just set guard time and Rdump for each.

[Tepco]

Hi WM6, I used ver 1.2.1 and also tried 1.0.1.

Author's words about latest (1.2x and up) version:" Ground balance is omitted, not justified for itself. Barrier and guard interval can be adjusted to minimize ground effect" (close enough translation). Some background "chattering" can be distinguished from steady target signal. I never finished my detector (handle, enclosure etc.), just bench tested whit ferrite, bricks etc, also i don't know how close SD2200 coil is and what adjustments may be needed. Maybe you have to try to "revert" software to some older version (known to handle GND effect well). I will write another post concerning this in more details ASAP.

This thing probably must be "customized" whit settings, coil etc. for different targets or ground conditions.

[mickstv]

I actually took the mono coil apart and found a faulty connection on the shield so I fixed that and it seems much better. But I will load an earlier version of the software again and see how it responds on the same ground.





Mick

[silverdog]

CHANCE Working

Ok, an update on CHANCE

after packing my eldest off to Uni, I finally got some time to play with CHANCE

It was ok after all !!

Having checked hardware changes over and over, mschmahl gave a big clue in a previous post, if you coil is not to spec you get the constant tone experienced by several people.

I adjusted the guard interval to 35 and away it went !!

My coil was a quickly made basket coil and although inductance was ok, I suspect my wire is too thin. I'll be making a better coil soon and will try and do a youtube video of it working.

Silverdog

[mschmahl]

Coil´s

I have played with different coil´s for the chance.
The coil must have at least 1,5 Ohm (i have done this sometimes with a 1 ohm resistor in series). If the coil have above 2,3 Ohm you have to change the dumpingresistor. My testet coil´s had between 250 uh and 650 uh.
The design of the coil and the thickness of wire isn´t important.
a cable reel works also( but unstable)

[Hannu]

I finally get Chance working. After soldering all connections second time I installed Hammerhead coil and everything start work. Guard interval was set to 25.
Coil spec: 0.566 mH, wire thikness=0.4, number of turns = 26.
I still need to try original basket coil.
Anyway "constant tone" is now gone away.

[sido]

Hi, I finished the chance PI project without the original required coil build. Just using a dual mono coil in series for now, but what i am getting is a tick tick noise (3 soft ticks per second) from the coil. The speaker sounds off tones randomly even if no metal present.

I will be building the recommended coil, but has anyone had the same issue like me (soft tick in coil noise)?

Everything else works fine, can adjust all settings, no overheating parts or high current consumption. All electrical devices turned off, TV, lights, chargers and computer during experiments.

Thanks Sido

[Hannu]

"I will be building the recommended coil, but has anyone had the same issue like me (soft tick in coil noise)?"
Yes. Some sound from (mono) coil when guard interval is set to 27.

"The speaker sounds off tones randomly even if no metal present"
This is happening when i'm using mono coil with shielding.

For me it's working much better with recommended coil.
I just don't know how to make shielding for this basket coil.

Hannu