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

[Aziz]

Can sombody explain me bether whot is magnet wire?
I can see we have bether caracteristic with ib-pi coil.
How can measure balance in this coil?
Measure voltage on output of rx diferent amplifier, controling current on bucking coil and try to
pick up minimum voltage on rx??
Azziz please thell me how you measure noise on some stage.With your scope or you calculate
this.Can i use usb digital scope to see noise..

Sorry for maybe my stupid question..

Regards!

Hi Miki73,

Magnet wire is enamelled copper wire. It has a very thin insulation and is usually used in coils, transformators or electric magnets (-> magnet wire). PI coils should use a different wire (with thicker low dielectric insulation, like PP or teflon, ..) to lower the interwire capacitance of the coil. VLF coils can be wound with magnet wire, as there is usually a resonant capacitor connected to the coil and the interwire-capacitance is not so dominant.

Induction balance is best achieved with two D shape coils (DD coil) by overlapping transmit (TX) and receive (RX) coil. The voltage induced in the RX coil should be as low as possible not to overload the input amplifier. The induction balance is achieved manually by setting one of the coils at a specified overlapped position (usually small overlapping area).

Induction balance by adjusting the bucking coil:
This coil type is usually a concentric co-planar coil with the main TX coil outside and the bucking coil inside (often half diameter). The bucking coil is wound in reverse direction referred to the TX coil but is connected in series with the TX coil. It has a specified number of turns to make a rough induction balance. The RX coil is often at the same diameter as the bucking coil with some distance gap to the bucking coil. Fine induction balance can be achieved by varying the distance gap to the bucking coil. This coil type is not for beginners and is quite difficult to make (to balance).
Make the DD coil. It's much easier.

Noise measurement (not for beginners):
I am using my sound card and a FFT software (spectrum analyser software) to measure the noise floor directly in decibel (dB). It is possible to see, how much noise is at a specific frequency (frequency-domain view). There are many software tools, which makes measurements and calculations easy (look in the internet).

You can use oscilloscope or usb scope as well to see the noise in time-domain view. However, it is difficult to measure the noise at a specified frequency.

One have to distinguish between the noise spectrum density (referred to bandwidth 1 Hz and specified for each frequency) and root mean square (RMS) for a specified bandwidth (for instance 0 Hz .. 10 kHz).
Have a look at the following site for further info:
http://www.ecircuitcenter.com/Circuits/Noise/Noise_Analysis/res_noise.htm
And the great internet (lot's of useful informations there).

Cheers,
Aziz

[miki73]

ib-pi coil

Can sombody explain me bether whot is magnet wire?
I can see we have bether caracteristic with ib-pi coil.
How can measure balance in this coil?
Measure voltage on output of rx diferent amplifier, controling current on bucking coil and try to
pick up minimum voltage on rx??
Azziz please thell me how you measure noise on some stage.With your scope or you calculate
this.Can i use usb digital scope to see noise..

Sorry for maybe my stupid question..

Regards!

[cko47]

Sound card for simulation of HH PI MD. Program

[quote=vistac2000;70303]Hi friends,
I almost new in http://thunting.com/geotech/forum, and see this site amazing and very interest about metal detectors,
at first I am sorry if my english is not very good ...

I wish with your helping, we can made a new PC-based metal detector with usb interface, this metal detector will can operate with pc or laptop very well and with some nice advantages, such as exact discrimination & even measure depth of target ! and others ...



I resolve synchronization problem in my program - Pulse Induction Analyser. It is working. But without complete Help and Settings form. You can try use this program with HH project.

[cko47]

Pulse Induction Analyser

There is a time limit, but (as you've now posted an updated version) I will leave the original to maintain continuity.

It is working version program but without complete Help and setting form. Problem with synchronization was resolved. Try this program with Hammer head PI MD. Connect to TP4 using R divider. Input signal must be less than 0.5 v.

Have a nice day

[cko47]

There is a time limit, but (as you've now posted an updated version) I will leave the original to maintain continuity.

Thank You for your reply.
You can write to me using my email (it is in application - Pulse Induction Analyser as attachment). I placed modified version (but again incomplete) in reply for WM6. Please visit to reply for WM6.
Changes and corrections of the mentioned program I make of each day. While not receive yet ready product. I shall be grateful for a finding of errors.
Have a nice day.

[Aziz]

I replace the attachment It had some errors.
How I can edit my message for changing attachment new version?. Excuse me for my bad English.
Thank You for your opinion.

Hi cko47,

good to know, I am not the only one, who plays with sound cards.
Well done.

Aziz

[Qiaozhi]

I replace the attachment It had some errors.
How I can edit my message for changing attachment new version?. Excuse me for my bad English.
Thank You for your opinion.

There is a time limit, but (as you've now posted an updated version) I will leave the original to maintain continuity.

[WM6]

I replace the attachment It had some errors.
How I can edit my message for changing attachment new version?. Excuse me for my bad English.
Thank You for your opinion.

Editing possibilities of posts are limited in time. After EDIT button near to your post dissapear you cannot edit your post anymore, but you can stil ask admin (Qiaozhi) to make some changes for you (as attachement replacement par example).

[cko47]

Great work cko47.
Congratulation and thank you.

I replace the attachment It had some errors.
How I can edit my message for changing attachment new version?. Excuse me for my bad English.
Thank You for your opinion.

[WM6]

I have created the program which displays an entrance signal from a sound card. The unfinished version is placed in the bottom of my message. I used the sound card. It has poor qualities therefore displayed signal in the program of distortion. But with the help of this program it is possible to simulate work of the detector. While the not complete version is placed bellow.
If to use a sound card of higher quality that of distortion should decrease. Sample rate must be > 96000 (96Khz or more), etc 192 Khz.

At connection of a signal it is necessary to reduce by an input sound card a signal up to 0,5 volts using of a divider. Differently sound card can burn (crashed) .
My PC
CPU 1.6 GHz
OS Windows XP
Sound card Realtek AC97 Audio
Lin input

Great work cko47.
Congratulation and thank you.

[cko47]

Sound card

Hi,
Thanks for ms.nomi and gwzd ...
yes, PDA can be better in light weight, but did PDA cpu enough for this job?

also programming of pda is which language? what is usb interface for PDA?
if you have any idea please share it to use for our purpose...

anyway,for laptop i found a usb interface with PIC18F4550 to start:
i am waiting for any idea, thanks...

I have created the program which displays an entrance signal from a sound card. The unfinished version is placed in the bottom of my message. I used the sound card. It has poor qualities therefore displayed signal in the program of distortion. But with the help of this program it is possible to simulate work of the detector. While the not complete version is placed bellow.
If to use a sound card of higher quality that of distortion should decrease. Sample rate must be > 96000 (96Khz or more), etc 192 Khz.

At connection of a signal it is necessary to reduce by an input sound card a signal up to 0,5 volts using of a divider. Differently sound card can burn (crashed) .
My PC
CPU 1.6 GHz
OS Windows XP
Sound card Realtek AC97 Audio
Lin input

[Aziz]

Hi Matar Maoz,

maybe you need such a configuration:

http://www.dlink.com/products/?pid=629

But I don't know, whether it will work.

Aziz

[Aziz]

I want to cut the middle of the USB wire.
In one side to put a transmitter, and in the other to put a receiver.
I have a set of one transmitter, and one receiver, using ASK.

the data is visual (web camera)

I am processing my data with a laptop.

I Know how to receive and process it on my laptop.
the only problem is that I dont know how can I combine between the two.

Matar Maoz

Hi Matar Maoz,

I am sorry, but I can't help you. You are trying to use a complete different application.
Just look in the internet. Maybe there is someone, who can help you.

Aziz

[metsik]

wireless

Would you describe, what you want to do? The PC/laptop/netbook/tablet PC is the core of the processing part.
Which kind of data would you like to transfer?
Which radio module are you referring to?

The ASK (amplitude shift keying) is a digital modulation type. Most of the available radio modules aren't suitable for this job.
Aziz

I want to cut the middle of the USB wire.
In one side to put a transmitter, and in the other to put a receiver.
I have a set of one transmitter, and one receiver, using ASK.

the data is visual (web camera)

I am processing my data with a laptop.

I Know how to receive and process it on my laptop.
the only problem is that I dont know how can I combine between the two.

Matar Maoz

[Aziz]

I want to seperate the detector from the pc by using a transmitter module and receiver module.

The problem is that I only have one ASK transmitter, and one matching receiver.
A friend of mine told me that I can short circuit my ground to the (D-) pin, and the data will pass through the (D+) pin correctly.

Is it true?

Would you describe, what you want to do? The PC/laptop/netbook/tablet PC is the core of the processing part.
Which kind of data would you like to transfer?
Which radio module are you referring to?

The ASK (amplitude shift keying) is a digital modulation type. Most of the available radio modules aren't suitable for this job.
Aziz