AVR+DSS Frequency Mod SD2100V2

[Qiaozhi]

Qiaozhi is correct the image does not display. im using Firefox an it does not display.Ive checked in Internet explorer on another pc and it does not display also.maybe its a browser plugin problem?regards Rov

I've tried Internet Explorer, Firefox, Google Chrome, Epiphany and Sea Monkey. None of these browsers can display the image.

The icon references an inline gif located on the Australian Electronic Gold Prospecting Forum, but I cannot get to that either.

IBGold - please attach the image directly to this forum. When you make a new post, scroll down the page and click on the Manage Attachments button.

[Jiminy]

I think the problem here is the fact that you have to be logged into the Australian Electronic Gold Prospecting site to see the photos there. I can see them here now as I am logged into both sites.

At least that is what I'm experiencing right now.

Ian, glad you had success. Good job!!!!!

/r
jonn

[mario]

Good thing it worked out Ian.

I have noticed a difference in sensitivity also with the few different coils at different frequency settings. It does seem each coil responds differently, with each having "a sweet spot" like you mention.

I'm looking forward to seeing that picture. 2.5 grams is a nice piece. If you like, you can email it to me, and I'll post it in my public google account.

Also, I've made a few changes to the software, but I don't think I will make it public since they're 2100V2 specific.

If they're any improvements you would like to see now that you've become familiar with the software, do let me know. I also use the software so it'll benefit me as well.

Mario

[IBGold]

OK for those that can not see the picture I will do it a different way I hope here goes the problem was I copied my post and pasted it here being lazy Hi.

Mario I will be in touch.

Regards, Ian.

[Qiaozhi]

OK for those that can not see the picture I will do it a different way I hope here goes the problem was I copied my post and pasted it here being lazy Hi.

Mario I will be in touch.

Regards, Ian.

That's better!.

[mario]

Ok guys, after speaking with Mick, he gave me an idea on how to rid ourselves of those cumbersome ground balancing pots.

I have not seen schematics for the SD2200v2 yet, but I'm certain it handles ground balancing in a similar manner.

Anyway, my plan now involves interfacing with a digital potentiometer like the AD5242. In short, I will be replacing the 2x100k 20-turn potentiometers with 1x AD5242BR100 (the 100k version).

I have already interfaced with the AD5242, and even wrote a library -which I don't mind making public (found here). I didn't find much on this device online, and it's a really cool chip to control.

In the next few weeks I'll be releasing the new schematic/software for interfacing with the AD5242, which involves a simple mount to a SOIC -> DIP board (like this one).

Just don't expect anything fancy. I'll probably implement ground balancing SD2200 style, with the push of a button.

I think this will be the last one guys.

However, keep the ideas coming and maybe we'll find something else to mod.

Like always, thank you for the suggestions and support.

Mario

[gef12]

HI Mario by the sounds of it ... you seem to be talking about the SD2000 and the 2 GB pots.. Agree some sort of better GB would be benificial to the users... good luck in your progress.

[mario]

Well, this little add on should also apply to the SD2000. If I'm not mistaken, Minelab also released them with manual ground balancing through the use of those 50k-100k pots.

Anyway, it seems like the AD5242 only has 256 positions, so the resolution will not be fine enough for our purposes...

I'm going to have to find another part...

[Jiminy]

What about the AD5231? It has 1024 taps and 100k?

[mario]

I thought about the AD5231.

Instead, I ordered the X9118 (X9118TV14IZ) (http://www.intersil.com/products/dev...=&js=&pn=X9118) because using I2C will simplify everything.

It seems like SPI (the interface the AD5231 uses) will require us to use 3 pins for SPI + 1 pins for addressing( total of 4 pins). Because we need 2x5231 in order to address Channel 1 and Channel 2, the pin count becomes much more manageable if we use the X9118 instead. For instance, with the X9118, we simply use the same 2 (I2C) pins to address up 4 devices .

Also, you can directly order from the manufacturer (clicking on the small shopping cart to the right) instead of relying on distributors.

I have them on order and will let you know how it goes...

[mario]

I need to make an update.

Work on the DSS project has been completed. I feel I have attained a good level of polish, and don't want to include unnecessary bloat. Last thing I want is redundant features. Currently, the program is very easy to use and powerful. This last update gives the user far more control over EMI, making these detectors substantially more quiet.

The archive included in this posting has all the necessary information to get a dss board up and running should any one here decide to undertake such a project. It includes the necessary schematics, binary, and detailed documentation.

I made last minute revisions to the schematic.

It now leaves open the possibility of future upgrades, like the current ground balancing project I'm undertaking. Having said that, I have made good progress with the X9118 chip, and I'm very impressed with the results.

I will be starting a new thread devoted to that second project since I plan on making these two projects independent of each other. However, I will give those who have the DSS boards the option of upgrading to ground balancing.

Since I have not finalized the hardware, I have not made the schematics for the ground balancing public. I'm currently debating if to implement something more meaningful like automatic ground balancing, which will obviously require additional hardware other than the two X9118 RDACs.

At 20 mips, we stand a chance at implementing some form of fft. I plan on doing something similar to what Garrett did with the emi handling in the Infinium, but with ground balancing, obviously.

If I don't, I will at least make the manual ground balancing public, which will be useful on its own right.

All in all, I'll try to make fewer, but more substantial posts on my next mod, so expect fewer posts when I do start making them.

It's a great time to own these older analog minelabs. Now that more and more people are becoming more comfortable with these microprocessors, these older minelabs will only get more functional.

[jtz54]

Hey Mario - was reading up on your project. I'd like to play around with the variable frequency concept on my 2100.
Where did you inject the signal on the 2100 board? A pic would be great. Thanks.

John

[Mechanic]

G'day John,

Is yours a 2100(original green) or a 2100v2? Cause they could be different.

Basically though, you have the large eeprom, the part next to that, moving toward the rear endcap edge of the board, you have a so16 package, which is a 74hc4040. Pin 10 is the clock signal for the 4040. If you lift that pin from its pad, you can feed signal into that, but make sure the voltage levels are correct. To be safe use a 1nf cap between your oscillator and the 4040.

Cheers Mick

Ps this thread will also be of interest to you.... http://www.geotech1.com/forums/showt...highlight=2100

[mario]

Hey Mario - was reading up on your project. I'd like to play around with the variable frequency concept on my 2100.
Where did you inject the signal on the 2100 board? A pic would be great. Thanks.

John

Hi Mick, Hi guys, long time no see.

John, download the files included with the project. One of them is an image with the correct connecting points.

I'm not sure what type of oscillator you are trying to use, but the signal has to be a very pure sine wave. Otherwise, it might be **very** problematic.

In short, the frequency:

1) has to very pure for timing purposes
2) has to be within a flexible range to avoid interfere

failure of the above 2 will lead to noise, which will prevent you from achieving any noticeable depth.

[jtz54]

Thanks Mario and Mick. Going to try one of the function generator modules at first. If that doesn't work too well I'll build your project (I'm a lazy guy). Just picked up Carl's book, maybe I'll learn a few things. It's forums like Geotech and guys like yourselves that make this hobby interesting and successful. Much appreciated.