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1185Re: [buildcheapeeg] Re: Alpha/Theta feedback

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  • Joerg Hansmann
    Sep 3, 2001
      Hi Vladimir,

      ----- Original Message -----
      From: Vladimir.K <gogol101@...>
      To: <buildcheapeeg@yahoogroups.com>
      Sent: Monday, September 03, 2001 11:08 AM
      Subject: [buildcheapeeg] Re: Alpha/Theta feedback

      > There is illustrative pictures of electrode placement:
      > http://faculty.washington.edu/chudler/1020.html
      > I hope, this will help you.

      Thanks. This picture is much more informative than my old one.

      > By the way, what variant of analog part EEG are you using ?

      It is the old gameportEEG input stage. Execpt for the higher
      supply voltage and other OPamp types after the INA114 stage,
      it is essentially the same analog part as in RS232EEG01.
      However there could be made some improvements regarding
      to limiting the the amplifier output voltage to the comADC input

      I have made a schematic that shows how to connect
      the gamportEEG analog part with comADC02 to get a
      (will be uploaded on my web-site at www.jhansmann.de )

      The pcb layout is not complete. However I assume, that
      the one channel comEEG can be built on
      a single sided half euro-size pcb (100mm x 80mm)

      > Do you generate tones by PC sound card ?

      Yes. The waveforms (at the moment simple sine waves, but it could
      be any waveform) are calculated in real-time and played with some
      lag (due to DMA-buffer size) via the wave output of the soundcard.
      Stereo output is supported (could be interesting for generating
      hemisync signals with the Monroe method)

      I am using the latest allegro3937 WIP version (multi-platform
      game-development library for DOS (with DJGPP), WIN9X and DirectX7 or later
      (with MSVC or MINGW32 - compiler), LINUX, BeOS, MAC OS)


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