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

[Qiaozhi]

I am thinking of to make one of those cheap sound-card RLC meters (impedance meter) rather than spending at least 100 EUR for an inductivity meter. I have found many interesting sources for this little project.
Cheers,

Aziz

Try this ->

http://cgi.ebay.co.uk/LCR-RCL-INDUCTANCE-CAPACITANCE-RESISTANCE-METER-DE3-/350225600301?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item518b128f2d

It's got to be cheaper than building one.

[Aziz]

Try this ->

http://cgi.ebay.co.uk/LCR-RCL-INDUCTANCE-CAPACITANCE-RESISTANCE-METER-DE3-/350225600301?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item518b128f2d

It's got to be cheaper than building one.

Thanks Qiaozhi,

yes indeed, a darn cheap device. But I don't want to wait 6-8 weeks for delivery. Its accuracy is not good too. It also could be kept in the customs due to counterfeiting issue.

No, I am dreaming of a much accurate, cheap and elegant solution. It seems, that I have to implement it by myself. Could be a nice feature within the metal detecting software.

We only have to do a nice complex math on a complex voltage divider. Should be really a trivial job.
Aziz

[Aziz]

Sound Card LCR Meter

Hi all,

I have built the small circuit of the sound card LCR meter (see below). It's really easy and cheap stuff. I have tested some available software for it. The only one, which works quite well is the Visual Analyzer software (see http://www.sillanumsoft.org/prod01.htm ) . You can forget all the other software stuff. Most of them did not run even. Others did not allow setting me the appropriate sound card device. None of them allowed a 24-bit/96 kHz sampling.

Well, I'll implement the LCR meter software by myself as I can do it much better than anyone on the planet.

Aziz

[Aziz]

Ok,

here is the theory behind the LCR meter:

http://icom.hsr.ch/uploads/media/RLC_Meter_EN_01.pdf (english)
http://icom.hsr.ch/uploads/media/RLC-Meter_DE.pdf (german)

http://www.sillanumsoft.org/ZRLC.htm

http://www.elektor.com/magazines/2008/june/an-rlc-meter-for-under-2-00.495109.lynkx

Aziz

[Qiaozhi]

Ok,

here is the theory behind the LCR meter:

http://icom.hsr.ch/uploads/media/RLC_Meter_EN_01.pdf (english)
http://icom.hsr.ch/uploads/media/RLC-Meter_DE.pdf (german)

http://www.sillanumsoft.org/ZRLC.htm

http://www.elektor.com/magazines/2008/june/an-rlc-meter-for-under-2-00.495109.lynkx

Aziz

Thanks Aziz. Very interesting project.

[WM6]

Try this ->

http://cgi.ebay.co.uk/LCR-RCL-INDUCTANCE-CAPACITANCE-RESISTANCE-METER-DE3-/350225600301?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item518b128f2d

It's got to be cheaper than building one.

Thanks Qiaozhi. I just ordered one. It has interesting measuring frequency in L range of 100Hz. I have no one L meter with such low measuring frequency. And maybe it is a clone of HP, look at this:

http://www.dealextreme.com/customerphotos/quarantined/26768-4e1b6d2e-42b6-4e25-b9f2-c44b1ea05d88.jpg

[Aziz]

Rolling the Ball and Folding

Hi all,

the projects are still going on. The annual electricity bill has been surprising me: I will get 9 EUR back. (I thought, I would pay a lot more. ) It seems, I can place an another order for the missing parts next month.

I have decided to buy an inductivity meter rather than making itself (more accurate for lower inductivity) . It's smart and convenient in the field too. It seems, I got bad ferrite ring cores. The specification varies heavily (wrong labeling ? - who knows) . So it was good to test them.

I also need new coil cables for further coil experiments. Either loudspeaker or mains line cables. I think, I have to spend 100-150 EUR just for cables.

In the coming days and weeks, I will investigate the suitability of Al foil roll as a cheap wire for coils. I have folded a 30 cm width, 30 m Al foil roll six times (2^6 = 64, giving 64 layers) . I got a very nice Al strip of approx. 5 mm width. It's DC resistance is approx. 0.2 Ohm. Maybe I should fold more Al foil rolls to keep the costs low.

Al foil: 1.45 EUR (30 m, approx. 13-14 µm thick, approx. 350 g weight)
Adhesive tape: 1 EUR
Total: 2.45 EUR

So the 30 m Al foil cable costs me only 2.45 EUR but it is causing a lot of work of course.
Hey, I am making only prototypes not a production line. So it's perfect for light weight big coils.

Back to folding until I get crazy....

Cheers,
Aziz

[WM6]

I think, I have to spend 100-150 EUR just for cables.

Even cheaper if you look for it in so called "Home improvement DIY" shops and not in electronic shop.

[Aziz]

Even cheaper if you look for it in so called "Home improvement DIY" shops and not in electronic shop.

Hi WM6,

yes, I know. In the krauts land, this does not seem to apply. Everything involved in home DIY products costs a lot of money.

But I am talking about 20-30 kg of copper wire.
No worry about the weight. This is only for a ground loop coil experiment. It's to keep the losses very low when transmitting with high coil power (> 20 A).

Aziz

[WM6]

But I am talking about 20-30 kg of copper wire.
No worry about the weight. This is only for a ground loop coil experiment. It's to keep the losses very low when transmitting with high coil power (> 20 A).

O yes, Aziz, I remember those your broad surface coil idea.
If you need Sherpas to smuggle around your lite coil, just mail me.

[Aziz]

O yes, Aziz, I remember those your broad surface coil idea.
If you need Sherpas to smuggle around your lite coil, just mail me.

I prefer the two-box type coil for deep detecting.

The Al strip wire could be a good choice for the big two-box type coil. Only the TX coil needs to be low resistance in this case.

Well I'll see, whether it is suitable or not.
Aziz

[Aziz]

Folding, folding, darn folding

New cost calculation for the aluminium strip cable (30 m length):
1 Al foil roll: 1.45 EUR (30 m, 30 cm, 350 g, 13-14 µm thick)
3 rolls of adhesive tape for insulation : 0.50 EUR (6 rolls for 1 EUR)
Total: 1.95 EUR

I am at the third Al foil roll currently. I have to organise a winding spacer strip (polystyrene strip 1-2 mm thickness). Well, I could cut some polystyrene sheets or take a double sided adhesive tape too. I have both at home but will look for a better one next time.

Still not crazy. But you have to be crazy to fold the Al foil roll.
Cheers,
Aziz

[WM6]

Still not crazy. But you have to be crazy to fold the Al foil roll.

Who say that crazy cannot enjoy in endless wrapping?

[Aziz]

Who say that crazy cannot enjoy in endless wrapping?

Hi WM6,

it's probably very boring. But the more I fold, the better it goes.

The Al stripe is really a very interesting cable. It makes a kind of "Litz-Stripe" (C) (R) by me . This cable is destined to the very high current carrying big two-box coil. And its weight is less. It is quite soft so it can be bent easily spiral like. The high interwire coil capacitance does not concern me.

I'll give a go to this interesting "super-market" coil wire.
I like it.

Aziz

[simonbaker]

Hi WM6,

it's probably very boring. But the more I fold, the better it goes.

The Al stripe is really a very interesting cable. It makes a kind of "Litz-Stripe" (C) (R) by me . This cable is destined to the very high current carrying big two-box coil. And its weight is less. It is quite soft so it can be bent easily spiral like. The high interwire coil capacitance does not concern me.

I'll give a go to this interesting "super-market" coil wire.
I like it.

Aziz

How about some photos, Aziz? I'm curious what it looks like, especially step-by-step.

Cheers,

-SB