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Digital processing for Pulse Induction MD with sound card

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  • Digital processing for Pulse Induction MD with sound card

    Use of digital processing allows considerably to simplify an electronic part of the detector. But to keep thus main units. It is a power unit, generator of pulses, preliminary amplifier and two (one) coils.
    For example for the project 22 it is possible to remove microcircuits IC7, IC8, IC9, I1C1, IC12 and components for them.

    The presence of metal is defined(determined) on change of the integated summ l for the chosen period of time . There is no necessity to move by the search coil to the left to the right. At a finding of the coil above metal object the sum of integration at once is increased.
    At 16 bit of sound card it is possible to catch even insignificant changes of this sum, that considerably increases sensitivity of the detector. The senstivity theoretically will be equal 1/16384. Actually it it is a little less, but substantial growth of sensitivity in comparison with existing types of detectors. (Pulse induction MDUsing regression analyses for digital processing of a signal allows to discrimanate of the metals.
    But it is necessary to know that resolution of the digital detector much more depends on a used sound card (if at processing a signal the sound card is used). The resolution on time depends on sample rates. And on amplitude from number bits (8, 16, 24 bits).
    The program made mine, is oriented on a card with 8/60 bits and sample rates (11025 to 48000 sps). It is possible to be switched to 8 bits at frequency 96000. But then the resoulution on amplitude (1/256) decreases.. Time resolution is 10 micro seconds (iti is considerably increased)
    The variant of my program of the pulse analyzer is placed below. And you can free downlload . But it is necessary to remember that the level of input signal (after the preliminary amplifier of the detector) must be less 0,5 volts. In mentioned variant of program is adjusted on a sound card Realtek AC97. If You to use other card that it is necessary to make changes to the program.
    Uploaded version of program is incomplete (without complete Help and settings options)
    Attached Files

  • #2
    full version PI Analyser

    Here is placed full version PI Analyser (ver 1.0) with complete Help and Setting form. But this program is oriented at Realtek AC97 sound card in notebook. When You have another sound card I can change source code of program. Tell me at [email protected] .
    In future new version 1.2 of PI Analyser can differentiate type of metal and viewing contours of target (metal). But it is not freeware. If You have questions for use the PI Analyser send email to me.
    Attached Files

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    • #3
      change in help

      last update in help file (chm)
      Attached Files

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      • #4
        Great !!!!

        Great work, that's what i was looking for

        Could you post the protection diagram? I don't want to damage my sound card...


        Keep up the good work !!

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        • #5
          Originally posted by cko47 View Post
          Here is placed full version PI Analyser (ver 1.0) with complete Help and Setting form. But this program is oriented at Realtek AC97 sound card in notebook. When You have another sound card I can change source code of program. Tell me at [email protected] .
          In future new version 1.2 of PI Analyser can differentiate type of metal and viewing contours of target (metal). But it is not freeware. If You have questions for use the PI Analyser send email to me.
          Hi cko47,

          hard coding of the sound card type is not the way of good software programming. You have to make it adjustable to the user.

          You also should feed the clock timing of the PI hardware to the sound card. The synchronization to the PI hardware would be much easier and accurate. As the sound card has two input channels (left/right), you can take one channel for the signal and another for the clock timing. Synchronization is very very important and is the Achilles' heel of the application.

          Aziz

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          • #6
            Hi Aziz!
            Thank for useful comments. I did not think that it will interest somebody. In last variant of the program the synchronization is considerably improved (second differentiate). But nevertheless it is necessary to find the necessary level of synchronization..
            The detecting of another sound card requires slightly to complicate the program. But it is possible. This application works in frequencies 900-2000 Hz.
            Width of sample and an initial point I can increase. It is simple. But I am interested by one. Whether somebody tried this program in work (search of gold nuggets)?

            best wishes

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            • #7
              Hi Solmer2!
              Be not afraid. The level of a signal should not exceed 0,5 volts. To reduce it you can using a simple RR divider. Besides you can reduce a level of a signal with the help of the control panel of a linear input (button of settings and button of windows volume control). In the electronics part of metal PI detector the maximal voltage can be about 5 volts. Means it is necessary to reduce it in 10 times or less. It is necessary to experementire. After measurement of signal level you can freely connect on an input of a sound card ( only linear input ).
              Read the help.
              Whether the well help works?
              have a nice day
              and excuse me for my bad English (my native is The Ukrainian)

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              • #8
                R divider for Line in

                " ...Could you post the protection diagram? I don't want to damage my sound card..."

                R1 50 K
                R2 5 K multiturn potentiometer
                Attached Files

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                • #9
                  Thanks

                  Hi cko47, thanks for the info and for the scheme

                  I find your project very interisting, keep up the good work !!!

                  Thanks again and don't worry about your English, the important thing is keep the info flowing, here you'll find people from all around the world (I'm from Spain) and who knows....even from MARS !!!!

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                  • #10
                    Hi Soilmer2!
                    Thank for Your support.
                    In some days I shall finish the manual for PI Analyser and upload it on a forum.
                    As far as I know gold nuggeds finds as the companions of rocks with increased radiation. Therefore I think to create in addition program for measurement of a radio-activity. It will work together with the previous program.
                    The search is not possible yet as at my region while in mountains still snow. Also it is necessary to wait while the level of water in the mountain rivers will be lowered up to an acceptable level.

                    Have a nice weekend
                    Last edited by cko47; 03-19-2011, 04:46 PM. Reason: adding info

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                    • #11
                      new method with good sensitivity for small gold nuggets

                      Originally posted by Geo View Post
                      Is the detector with 2 or with 4 knobs???
                      As a result of long researches of the PI metall detector with use of digital processing of the received signal was determined the following. The integration of a signal has not good sensitivity and for digital processing for the large time of discretization this method is poorly sensitive. The program of my new method allows considerably to increase sensitivity of such PI detector (even at use of a sound card with the maximal sample rate 192 000). At its use such PI detector (with digital processing at sound card) very well reacts to gold nuggets even of the small sizes.
                      I remind that my program can work only on portable computers with a sound card, which has a line input and SPS 192 000 and for Windows XP. New parameter in my program is designated by the letter М.
                      PS. For this programm I use only 2 knobs - freq and pulse width.
                      Attached Files

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