Mirage PI Project, anyone interested?

[Hammerhead]

All thanks and appreciation to Mr. Seven received today electronic components and successfully plan my friend now detector Mirage in Alexandria

[Tim]

hebcom, I have an ebay Tacoma56 SMpro DD. Not sure if his still come set up for DD, but with a 10x5 MLcommander (DD) coil I get 4+ inches on a 1.7g flour gold sample, air test on lowest delay. Other things worth trying would be the VSAT mod here, and maybe adjusting appropriate components related to delay.
I have the GMT too, and, yes, there are only certain spots here it can cope. But it will find the super-smalls there.

geocash this is what I would call a spider coil. There is an article here somewhere regarding Mike Tuggle's "spider"coil. They too have great potential for a fast coil.
My MPP and Chance boards from Silverdog are on the shelf while I finish my Cert II Horticulture.

[geoscash1]

Thanks Sven and George for your recommendations, much appreciated! I'm going ahead and order the MPP from Andy (Silverdog) and follow KRinAZ steps to get down to around 6us delay. I'm going to start building a basket weave 8" coil to try it out with the SM Pro and the MPP as soon as I finish it. Right now I have two coils I've built a 300uH 8 inch and 340uH 11inch besides my 6" Razorback which is also @ 300uH. I'll report back as soon as I build the MPP and text it with the different coils.

Thanks for your help!

I also have built the MPP (x2) and also use a 6x10 razorback long reach, it works excellent with the mpp and I can sample to 6us. It air tests an 8 gr (.45g) nugget at 2 inch with the delay set to 8us. My original coil, a spider (3dss according to some) at 7.5in/312uH with 250/45 litz, it works almost the same as my razorback, 1-3/4" on the 8gr nugget. I believe my razorback is 300uH as well with shielding, it was designed and made for the whites TDI.

My mirage can be set to 8us as well and with a 7inch 300uH coil (litz or Teflon 600v 26/awg) works almost as well.
You will be happy with either one but the MPP has just a tad bit more capability as far as mods go, KRinAZ (Kyle from Arizona) did a great job with the mods for gold.

[hecbom]

Thanks Sven and George for your recommendations, much appreciated! I'm going ahead and order the MPP from Andy (Silverdog) and follow KRinAZ steps to get down to around 6us delay. I'm going to start building a basket weave 8" coil to try it out with the SM Pro and the MPP as soon as I finish it. Right now I have two coils I've built a 300uH 8 inch and 340uH 11inch besides my 6" Razorback which is also @ 300uH. I'll report back as soon as I build the MPP and text it with the different coils.

Thanks for your help!

[SVEN1]

You could calibrate the Mirage to sample down to 8us.
But, the intent was to make a very small gold jewelry detector mainly for beach hunting with as much depth as possible.
When I calibrate the Mirage at min. pulse delay for a gold nugget of 12 grains to about 4-5" depending upon search coil. At that point it will pick up a 3.2 grain nugget at about 1 to 1 1/2" from the coil.
I know my friend has his pick up a 1.5 grain gold nugget under 1" of black sand. I was going to set up a Mirage for Micro jewelry for another fellow when I got around to experimenting again.

The Mini-Pulse has a lot of potential, like George says, you may want to look at it. Right now that might be your best option.

[Qiaozhi]

Qiaozhi Thanks for the info! I was not aware the Minipulse Plus had a two stage pre-amp. I guess I need to look at the schematics and read the description of the build. I still need to get down to less than 10us in order to detect small gold and that is one of the reasons I am closely following the Chance PI. I don't have any experience programing the Atmega328 but that should not be any different than programming other pics except I will have to learn to use avrdude. I will take your advice and follow up with KRinAZ mod.

KRinAZ was able to get down to 6us sample delay.

[hecbom]

Qiaozhi Thanks for the info! I was not aware the Minipulse Plus had a two stage pre-amp. I guess I need to look at the schematics and read the description of the build. I still need to get down to less than 10us in order to detect small gold and that is one of the reasons I am closely following the Chance PI. I don't have any experience programing the Atmega328 but that should not be any different than programming other pics except I will have to learn to use avrdude. I will take your advice and follow up with KRinAZ mod.

[Qiaozhi]

Sven

Can the Mirage work in the sub 10us range? I'm asking because at our Club's claim near Quartzsite Az. my GMT will not work in the highly mineralized soil at this location. As I'm sure most in this Forum know, a PI is the only way forward. So after much thought and trying to justify the expense of buying either a White TDI SL or a ML GPX 4500 I decided to build two PI to see how they would work at this location. My first PI an SM Pro will not pick up the small Gold in this area and either did my second PI 1 (page 163) from (Inside the Metal Detector) both built and tested before hitting the field. A typical gold sample at Quartzsite would be in the range of 1 to 3g and if you are lucky, you might hit a larger specimen. BTW both detectors were tuned for a "Razorback" 6" mono.

Cheers!

You might also want to try the Minipulse Plus with KRinAZ's modifications.
Minipulse Plus REV-D
Completed Minipulse Plus Projects by Geotech members (look at Post #7)

[hecbom]

Sven

Can the Mirage work in the sub 10us range? I'm asking because at our Club's claim near Quartzsite Az. my GMT will not work in the highly mineralized soil at this location. As I'm sure most in this Forum know, a PI is the only way forward. So after much thought and trying to justify the expense of buying either a White TDI SL or a ML GPX 4500 I decided to build two PI to see how they would work at this location. My first PI an SM Pro will not pick up the small Gold in this area and either did my second PI 1 (page 163) from (Inside the Metal Detector) both built and tested before hitting the field. A typical gold sample at Quartzsite would be in the range of 1 to 3g and if you are lucky, you might hit a larger specimen. BTW both detectors were tuned for a "Razorback" 6" mono.

Cheers!

[homefire]

Could you please post a parts list ?

[SVEN1]

The German Forum a few years ago used an early version as a winter project build. Think Bernte One. headed up the project and I believe they all made up their own PCB from the Sprint files I supplied. http://www.detektorforum.de/smf/eigenbaugerate_tuning/mirage_pi_das_winterprojekt_2013-t66670.0.html;highlight=mirage

The latest version has a number of PCB changes, trace changes, part value changes and part positioning.........
We removed the pinpoint button option. Pinpointing is fast and easy with out it, nice but feature , not needed. I rarely if ever needed to use it.
The iron check we talked about long ago, we didn't think it was worth the trouble or was needed but, could be added at any time. We were trying to keep
the panel controls to a minimum. We didn't want to end up with a detector with 100 different adjustments like the Blisstool.

Yes, a 10 turn frequency pot makes a big difference in tuning, at times a micro adjustment is only needed. With a 1 turn pot, its very hard for many to make such a small hair line adjustment.
[IMG][/IMG]

[WM6]

Nice distinguish solution for small parts of nonferrous metal (with short TC).
For bigger parts (like say: bronze statue) it is better to discriminate by eyes.

[württemberger]

It´s not realy a Disc... With my mod. you can only check if the signal
Ferro or Non-Ferro Metal. The Test-Button only shift the 1. Sample delay to 85µS.
It´s very simple, but effectiv.

[WM6]

Hi Sven,

this is my mod. Version from your Mirage 2014.
It has a simply Disk and a DC-DC Converter

Very Pro design.
With "Disk" you mean discrimination? Which part of circuit serve like this?
Is "Disk" genuine Sven solution or your mod?

[württemberger]

Hi Sven,

this is my mod. Version from your Mirage 2014.
It has a simply Disk and a DC-DC Converter