Loading ...
Sorry, an error occurred while loading the content.

Re: comADC-EEG

Expand Messages
  • Vladimir.K
    ... I ve finished older variant of comADC-EEG , the gameport. ( I used TLC272 and 9V Battery). Now, I am reading gameport on old Linux box and sending to other
    Message 1 of 27 , Oct 4, 2001
    • 0 Attachment
      --- In buildcheapeeg@y..., "Joerg Hansmann" <info@j...> wrote:

      > It is a quick and dirty prototype. The GUI is not finished.
      > All setup is via #define in the source.
      > So if you want to run it on your PC you probably
      > have to make some adjustments and recompile
      > it with DJGPP (and the allegro gaming library).
      >
      > If you are not scared until now, I can mail you the
      > source code and/or the executable.
      >
      > Regards,
      >
      > Joerg

      I've finished older variant of comADC-EEG , the gameport.
      ( I used TLC272 and 9V Battery).
      Now, I am reading gameport on old Linux box and sending to
      other machine (W98) to Electric Guru.

      Even some experiment with kernel Real Time extension ( KURT ) and
      altering parameters in joystick driver, results are not perfect. It's
      only 120MHz Pentium.


      I would like to try your code for DOS, so if you can, send me, please
      it. (gogol101@...)

      One curiosity:
      I didnt think that 9V is dangerous, but when I mesured resitance of
      EEG electrod ( home made saline type ) I got el. shock and becaus
      I had electrode on forehead near eye so I saw light flash.
      ( I have 9V battery in Ohmmeter).

      If I remember, you said that RS232EEG is limited to 8( or 6 ) channels
      for limited bandwith on RS232 ( 115 kbaud).
      I was suprised when I saw on Linux possible setting for 230 and 460
      kbaud. I am curious if so high speed is real.

      Regards
      Vladimir
    • Joerg Hansmann
      Hi Vladimir, ... From: Vladimir.K To: Sent: Thursday, October 04, 2001 6:20 PM Subject: [buildcheapeeg]
      Message 2 of 27 , Oct 5, 2001
      • 0 Attachment
        Hi Vladimir,

        ----- Original Message -----
        From: Vladimir.K <gogol101@...>
        To: <buildcheapeeg@yahoogroups.com>
        Sent: Thursday, October 04, 2001 6:20 PM
        Subject: [buildcheapeeg] Re: comADC-EEG


        ...
        > I've finished older variant of comADC-EEG , the gameport.
        > ( I used TLC272 and 9V Battery).
        > Now, I am reading gameport on old Linux box and sending to
        > other machine (W98) to Electric Guru.
        >
        > Even some experiment with kernel Real Time extension ( KURT ) and
        > altering parameters in joystick driver, results are not perfect.

        What sample rate and how many bits resolution do you get ?

        > It's
        > only 120MHz Pentium.
        >
        >
        > I would like to try your code for DOS, so if you can, send me, please
        > it. (gogol101@...)

        I will send it via email.
        However it is for the comADC02 hardware.

        > One curiosity:
        > I didnt think that 9V is dangerous, but when I mesured resitance of
        > EEG electrod ( home made saline type ) I got el. shock and becaus
        > I had electrode on forehead near eye so I saw light flash.
        > ( I have 9V battery in Ohmmeter).

        A normal ohmmeter is not very suitable for measuring electrode
        impedance, because it uses DC (resulting in electrode
        polarization) and probably exceeds the limits of IEC601-1
        (therefore you got the electric shock and the light-effects)


        > If I remember, you said that RS232EEG is limited to 8( or 6 ) channels

        6 channels, because the AT90S4433 has only 6 analog multiplexer inputs.

        > for limited bandwith on RS232 ( 115 kbaud).

        There are other limiting factors too like ADC conversion speed.

        > I was suprised when I saw on Linux possible setting for 230 and 460
        > kbaud. I am curious if so high speed is real.

        If the UART chip on the mainboard can handle that speed, I see no
        reason why such settings should not work.
        For RS232EEG however the upper limit is 115200 baud due to
        xtal-frequency and minimum possible baudrate divider factor.

        Regards,

        Joerg
      • Vladimir.K
        Hi Joerg, sory for late answer, I am busy now. ... I have not mesured it yet. My etimation that it s worse than 8 bit on 256 sampling. Now 256 samples per
        Message 3 of 27 , Oct 11, 2001
        • 0 Attachment
          Hi Joerg,

          sory for late answer, I am busy now.

          --- In buildcheapeeg@y..., "Joerg Hansmann" <info@j...> wrote:

          > What sample rate and how many bits resolution do you get ?
          >

          I have not mesured it yet. My etimation that it's worse than 8 bit
          on 256 sampling. Now 256 samples per second is too high.
          But there is growing potencial. I saw some tricks with setting
          interrupt-unmask flag for IDE driver ( prog. hdparm ) and
          IRQ priority optimalization. ( www.best.com/~cae/irqtune/ )
          Maybe ideas from irqtune are also worth for DOS programs.

          I also don't understand all code in joystick driver.

          > I will send it via email.
          > However it is for the comADC02 hardware.

          Than you.

          Regards
          Vladimir
        • Joerg Hansmann
          Hi Vladimir, ... From: Vladimir.K To: Sent: Thursday, October 11, 2001 3:01 PM Subject: [buildcheapeeg]
          Message 4 of 27 , Oct 13, 2001
          • 0 Attachment
            Hi Vladimir,

            ----- Original Message -----
            From: Vladimir.K <gogol101@...>
            To: <buildcheapeeg@yahoogroups.com>
            Sent: Thursday, October 11, 2001 3:01 PM
            Subject: [buildcheapeeg] Re: comADC-EEG


            > Hi Joerg,
            >
            > sory for late answer, I am busy now.

            No problem.

            >
            > --- In buildcheapeeg@y..., "Joerg Hansmann" <info@j...> wrote:
            >
            > > What sample rate and how many bits resolution do you get ?
            > >
            >
            > I have not mesured it yet. My etimation that it's worse than 8 bit
            > on 256 sampling. Now 256 samples per second is too high.
            > But there is growing potencial. I saw some tricks with setting
            > interrupt-unmask flag for IDE driver ( prog. hdparm ) and
            > IRQ priority optimalization. ( www.best.com/~cae/irqtune/ )
            > Maybe ideas from irqtune are also worth for DOS programs.

            While the gameport timing loop is running, simply no interrupt must
            be processed. Or are you using another technique than polling ?

            IMO the advantage of simple and low cost hardware of the gameportEEG
            or comEEG is more than compensated by the resulting difficulties with
            software.

            Regards,

            Joerg
          Your message has been successfully submitted and would be delivered to recipients shortly.