Let's made a PC-base metal detector with usb interface !!!

[Aziz]

BTW,

this new platform is an experimenting platform as well. Particularly for me.

I want to try a different VLF detector system for extreme mineralized grounds/soils. If all things go well, we will achieve extreme depth, good ground balancing and discrimination possibility. This VLF detector will make use of the benefits of the findings made before.

So I'm just doing this for the reason of curiosity. If this isn't working, well there are more configurations, which are doing really well.

Let's engage our weapons ... ups... our coils.

Aziz

[WM6]

there will be a "detector war" soon.

Aziz, you will be in peace keeping forces.

[Aziz]

Hi all,

I have been quite lazy last days due to other projects & things.

Well, I have put some more parts to the current circuit and I hope, they will fit into the pcb board. Otherwise, we have to put some resistors and diodes vertical, which do not occupy much area then.

The circuit modification extends the operating voltage range (down to 9V and up to 30V). The mosfet driver has it's own power supply (15-16 V) and is generated from a DC/DC converter. Analog power supply is also generated from the DC/DC converter (+/- 7-8V). The DC/DC converters are synchronized to the pulse timing of course. This modification has lot's of benefits and I want to have it at all cost.

Cheers,
Aziz

PS: We are heading to interesting times and there will be a "detector war" soon.

[yalnizefe]

Designing a Digital Lock-In Amplifier with Sound Card

http://digital.ni.com/worldwide/singapore.nsf/web/all/474BA4D976DEFC548625703D00446948

A low-cost, high-performance, digital signal processor-based lock-in amplifier capable of measuring multiple frequency sweeps simultaneously

http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=RSINAK000076000002024703000001&idtype=cvips&gifs=yes

A first version of a low supply voltage (2 V) fully integrated lock-in amplifier, designed in a standard CMOS technology (AMS 0.6 μ), is presented.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6THG-43HJVDR-1D&_user=1496926&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000053094&_version=1&_urlVersion=0&_userid=1496926&md5=2d6707887f3620a3272f83222488d033

A Microcontroller Based Digital Lock-In Milliohmmeter

http://www.cappels.org/dproj/dlmom/dlmom.html

Take you pick

hello members Gotech form (cscope 990) metal detector to chart the need to help me thanks

[Aziz]

More Interesting News

Hi all,

the next version of Microsoft Windows (TM), the Windows 8 (or so), should support touch pad functionality too. We will see nice Tablet PC's with extended operating durations (using new Atom or ARM processor).
Watch out, Samsung (or other competitor) could bring out the first interesting running Tablet PC for Windows 8.
7 inch form factor Tablet PC's with USB support are the interesting platforms.

Aziz

[Aziz]

Interesting Times Ahead (Tablet PC's)

Hi all,

did you see all the new interesting late Tablet PC's on the market? It's going to be very interesting soon. Looks like, I've to support Android O/S as well. Well, I tend to let it to mature a bit (let them time to get rid of children's disease).

Samsung Galaxy Tab looks very interesting to me. Unfortunately, a very bad ******* company (well known as a patent troll) has stopped the Galaxy Tab selling in Europe. This thing must be sooooo good, that the bad company plays obviously an unfair game.

Cheers,
Aziz

[Aziz]

Hi all,

funny stuff. I'm approaching more and more to the professional version of my detector.
But the funny stuff is, that it's still "light" and simple. And it gives more benefits and flexibility too.

I have decided to drop the active power supply filter and to add bipolar power supply to the analog section. At the end, it ends up with almost the same amount of parts. And I can change to some very low noise op-amps/instrumentation op-amp as well. Due to the new layout arrangement, there is some more space on the board too.

The high power section is now perfect and need no further modification (looks like I'm satisfied with it). Now I hope the new changes will fit into the board.

Cheers,
Aziz

[Aziz]

Hi all,

there is a much much better PCB layout possible. I'll rip(up) the current PCB and make this little beast completely new. It was a good decision to wait with the bread board wiring. Nevertheless, it's difficult to control the auto router. But it delivers good information about the parts placement.

Cheers,
Aziz

[Aziz]

Good achievement Aziz.

But wired this under choke may prove as very poor solution:

Thanks WM6,

a good point indeed. I'll try a different layout.

Aziz

[WM6]

Vias = 0!

Good achievement Aziz.

But wired this under choke may prove as very poor solution:

[Aziz]

Sure is pretty. What layers are we looking at? Is there a list that would show the vias?

-SB

Red=Top, Blue=Bottom. The PCB isn't finished for production however.
There will be generated a protocol file after the auto routing (*.pro):

EAGLE AutoRouter Statistics:
Job           : <xxsecretxx>.brd
Start at      : 01:38:13 (09.09.2011)
End at        : 01:38:15 (09.09.2011)
Elapsed time  : 00:00:02
Signals       :    43   RoutingGrid: 50 mil  Layers: 2
Connections   :   195   predefined:  113 ( 0 Vias )
Router memory :   24992
Passname          :     Route Optimize1 Optimize2 Optimize3 Optimize4
Time per pass     :  00:00:00  00:00:00  00:00:01  00:00:00  00:00:01
Number of Ripups  :         0         0         0         0         0
max. Level        :         0         0         0         0         0
max. Total        :         0         0         0         0         0
Routed            :        82        82        82        82        82
Vias              :        10         0         0         0         0
Resolution        :   100.0 %   100.0 %   100.0 %   100.0 %   100.0 %
Final             : 100.0% beendet

Vias = 0!

[simonbaker]

Hi all,

this is what I get when I run auto route script. Only minor cosmetics required. No via's (I think). It's not bad finally.

Sure is pretty. What layers are we looking at? Is there a list that would show the vias?

-SB

[Aziz]

Hi all,

this is what I get when I run auto route script. Only minor cosmetics required. No via's (I think). It's not bad finally.

[Aziz]

I assume the pad and trace were on opposite sides of board so no real danger!

I hope later you can tell us some of these Eagle auto-routing tricks you use, because it can be difficult to control auto-routers.

Route-on!

-SB

I find, that individual shaped signal planes (polygons) direct the auto router much better instead of using obstacles. Pity, manual routed signals are lost if you type the "ripup;" command. One need something like "lock" feature. The ripup command can exclude signals from beeing ripped. The polygons are still there after ripup command however.
All the ground planes and high current routing path are made with signal polygons therefore.

Well, the auto router is very dump and creates often obscure routing result. It causes a lot of work for fine tuning (cosmetics).

The reason, why I use the auto route script is, that the DRC rules apply always. Otherwise, it won't route the signals (as Mr. Q mentioned).

The new PCB is looking better.

Aziz

[Qiaozhi]

Hi SB,

this actually isn't critical. But I see, the analog ground of the IC isn't optimal connected to the bypass capacitor due to an obstacle. I have found a much better way of directing the auto router instead of putting obstacles now. I'm sure, I can have a much better result this time.
Cheers,
Aziz

If it passes the DRC checks, then it will be ok.