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

[Aziz]

The Great Big Rip-Off

Hi all,

I was again ripped off by the resident evil german government due to illegal demands. I had nothing, so they again got nothing except my contempt on their attempt of grand larcency. I did not agree to be ripped off by my consent. So I refused to give my consent ("Eidesstattliche Versicherung"). At this stage, I might be illegal arrested by the thiefs ("Haftbefehl").

Nothing to worry about.
I will take a break from the projects and play as an amateur advocate. So I have to make an application for foreclosure suit ("Vollstreckungsabwehrklage").

The enemy is not sleeping. But I can sleep very well.

Take care,

Aziz

[Aziz]

Ahhhhhg!

I am sorry, but all the current projects will be delayed again.

Probably for a longer period of time.
Reason: Developing a new method, which has the knock out potential for current detector technologies.

Cheers,

Aziz

[Aziz]

Project States

Hi all,

I want to give you some update on project states:

Jail project:
Still going on. Due to perversity of german justice, this could easily be happen to me here in the kraut's land. In case of this, I will call the European Court of Human Rights.

VLF projects:
Not following anymore. Enough played with toys.

IB-PI:
This is achieving very good performance (bloody high sensitive). Unfortunately, it needs an induction balanced coil (you know, I hate them). The new board has not been started yet. But I did further interesting tests with my old board in the mean time. You wouldn't believe me: The receive coil signal can just be fed directly into the sound card input line without any amplification (needs a high voltage protection only). The bandwidth and dynamic range of the 96 kHz/24-bit sound card is high enough for direct ADC sampling and processing.
It's quite powerful, robust and power efficient. But it's major benefit is an outstanding ground balance/discrimination possibility. With an additional receive amplifier, the sensitivity can be increased much further (20-40 dB gain enough for this).
You can process the digitized receive signal either in the time-domain or in the frequency domain (both working). Even the digital integration and windowing works fine. The main limitting factor is the coil stability (IB coil!). If your coil gets hot, then the induction balance gets mismatched a bit. So heat in the coil is another problem, if your coil has high resistance.

Anyway, this version will be definitely one of my alternate detectors. It's a very simple architecture and delivers outstanding results.

PI Controller:
Still waiting due to limitted resources. I have been thinking of making a light & simple version before continuing this project (see below).

New project:
PI Resampler:
The project objective is moving towards simple & robust designs (I need some field data and it should be a base for some further experiments):
MONO coil, simple architecture, robustness in the field

Problem: Very fast decaying signals, but a slow ADC (96 kHz sound card)
Solution: A micro controlled fast sampling and slow resampling hardware architecture. A simple 8-channel sample & hold stage will do this easily. A short period of time will be sampled and then presented for a longer duration of time to the sound card. The timings will be controlled by the micro of course. That's all.

Good luck to me.
Cheers,

Aziz

[Aziz]

Hi zendurla,

07-12-2010 03:08 AM
zendurla

Hello Aziz I have a question for you what if I buy a Spectrum Analyzer like this one http://www.soft32.com/Download/free-...-126737-3.html & put it on my laptop - Question is how would I connect the output from the MD (headphone) to the Mic of my Notebook or hand held computer?

I am sorry, but I did not see this on my profile (visitors message). I never look at it.

No, we don't need such spectrum analyzers. We will implement this in a better way of course. Laptop/Netbook offers much more computation power. BTW, we are not interested on the whole spectrum. We just need some of the following frequency spectrum components:
1*f0, 2*f0, 3*f0, .. , n*f, (f0 = fundamental transmit frequency).

I generally do not use the MIC input (often mono, high gain and noisy). I prefer stereo line input (left & right channel).
The receive signal will just be amplified and fed into the stereo line input (two channel receive signal).

The simple PI detector I am currently working will do all the signal processing on the two time-domain input signals only.

Aziz

[danny475bek]

i get it

but untill now i dont see any of thoes microcontroler based detectors that work well and have more functions and have a usb interface with a pc
i know that micros are judt games although they are games but untill now i dont see a full and complet detector with a big lacd screen and more controling functions
so first w have to build that one and than we are goilg to go to the next step
take care all of you
by by

[Aziz]

Hi danny475bek,

No, micro controllers are just toys referring to computation power. But I need huge, really huge computation power for some secret reasons.

Aziz

[danny475bek]

HI

hi i'm danny bekerejian a graduate of technical computer
i guess it is beter to build a microcontroler based matel detector
you are not taking in concederation the price or the detector nor the pakaging .....
who sad that microcontrolers are in law speed no they can act as the same as computers and who sad that we will put the comparation in the cpu no
the cpu only for good interface
most original matal detectors are microcontroler based

[Aziz]

Project Update

Hi all,

I will take a break on the projects. The reason is, I am total bankrupt. No, the krauts did not rip me yet. Because, there is nothing to rip.

BTW, I am 44 years old and they want to retire me now.
That's a bit too early - isn't it?

Aziz

[mr cleo]

metal detector/usb interface

im runing a icon data logger with a minlab exp 2 getting good results
www.imagelocators.com need to run in vco (non motion mode to work)
vary good with pi.look for me sep 1st on above site.

[Nicolas]

Hi all

Good Thx

[Aziz]

Noise Analysis with LTSpice

Hi all,

I just want to mention: Be very very careful when you are making some noise analysis with the internal parts of LTSpice.

Some of them seem not to behave correct.
Try the different LT1028 and you will see what I am meaning (there are four different models: LT1028, LT1028A, LT1028CS, LT1028N).

Even the n-jfet 2n4393 seems not be behaving well when making noise analysis. It's resistor noise isn't there, but it should be. It's behaving like a 2 Ohm resistor noise instead of 100 Ohm.

But the 0.7 nV/sqrt(Hz) amplifier noise above is correct: It's the fully differential input noise density. The transimpedance (I-to-V conversion) is made by two independent op-amps and hence reducing the differential noise. The single ended noise is higher of course (+3 dB).

I will check soon, whether we need a super-low-noise amplifier.
Aziz

[WM6]

Hi WM6,

you are confusing me.

FPGA = Field Programming Gate Array (http://de.wikipedia.org/wiki/Field_P...ble_Gate_Array )
PGA in this context = Programmable Gain Amplifier (http://en.wikipedia.org/wiki/Program...gain_amplifier )

My project has nothing to do with FPGA's. I don't need it at all.

You will find here a PGA implementation:

http://www.ecircuitcenter.com/Circuits/op_PGA/op_pga.htm

Aziz

Eh abbreviations, Aziz, you go so fast in the future, that I am no longer capable to catch all your bright thoughts and attempts. Thanks.

[Aziz]

Secon part of my previous post

"But are you sure about FPGA? You ca set multiple amplifiers input inside PGA too? "

is refering to this:

Hi WM6,

you are confusing me.

FPGA = Field Programming Gate Array (http://de.wikipedia.org/wiki/Field_P...ble_Gate_Array )
PGA in this context = Programmable Gain Amplifier (http://en.wikipedia.org/wiki/Program...gain_amplifier )

My project has nothing to do with FPGA's. I don't need it at all.

You will find here a PGA implementation:

http://www.ecircuitcenter.com/Circuits/op_PGA/op_pga.htm

Aziz

[WM6]

Secon part of my previous post

"But are you sure about FPGA? You ca set multiple amplifiers input inside PGA too? "

is refering to this:

No, it's not a PGA. The PGA-switches in the feedback loop path would contribute much noise to the amplifier. Not good. PGA-idea is dead.

But the concept of having several amplifiers is much better regard to stability, noise and temperature dependency.

[Aziz]

Sorry, by mistake from the end of first page, post #35. So crauts live everywhere. But are you sure about FPGA? You ca set multiple amplifiers input inside PGA too?

Sorry, can't find the context. Can you give the referring absolute post number? Then your questions.
Aziz