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Re: [buildcheapeeg] Re: hi folks

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  • Joerg Hansmann
    Hi Rob, ... From: Rob Sacks To: buildcheapeeg Sent: Thursday, November 30, 2000 7:24 PM Subject: Re:
    Message 1 of 16 , Dec 1, 2000
      Hi Rob,

      ----- Original Message -----
      From: Rob Sacks <editor@...>
      To: buildcheapeeg <buildcheapeeg@egroups.com>
      Sent: Thursday, November 30, 2000 7:24 PM
      Subject: Re: [buildcheapeeg] Re: hi folks


      > Joerg,
      >
      > (If I write your name this way, Jörg, does it work?)

      Yes. It looks right. ( A little trick with the ALT-Key ? )

      > > Sounds nice. I am really interested in samples of brainwaves of a meditating
      > > lama. Perhaps Rob could add the feature of recording / viewing
      > > eeg-data files.
      >
      > What should we put in the files?

      e.g.

      1 header:

      4 bytes version_code
      80 char short_description
      1 byte number_of_channels
      1 byte bytes_per_channel
      ?? bytes date_and_time_of_recording_start

      n data-blocks:

      1 byte ch1_hi
      1 byte ch1_lo
      1 byte ch2_hi
      1 byte ch2_lo
      ...
      1 byte chn_hi
      1 byte chn_lo

      ------------end_of_format_description-----------

      As an alternative we could use a data format of commercial
      eeg data logger.

      > If we store all
      > the data (the raw serial input or the microvoltages)
      > the files will be very big.

      If you provide a dialog to store only channels that are used,
      the amount of data will be quite moderate for modern PCs.

      1 second : 256Hz * 2 channels * 2byte/channel = 1024 bytes
      1 minute : 60* 1024 bytes = 61 kB
      1 hour: 60* 61kB = 3.7 MB
      24 h : 24* 3.7 MB= 88 MB

      Lets assume , the lama meditates 1 h , then we would get 3.7 MB
      raw data. Compressed to ZIP -Format it will be below 1 MB

      Regards,

      Joerg
    • Joerg Hansmann
      Hi, ... From: Brian Earle To: Sent: Thursday, November 30, 2000 4:37 PM Subject: Re: [buildcheapeeg] Re:
      Message 2 of 16 , Dec 1, 2000
        Hi,

        ----- Original Message -----
        From: Brian Earle <bearle@...>
        To: <buildcheapeeg@egroups.com>
        Sent: Thursday, November 30, 2000 4:37 PM
        Subject: Re: [buildcheapeeg] Re: hi folks


        > Rob,
        >
        > > What should we put in the files? If we store all
        > > the data (the raw serial input or the microvoltages)
        > > the files will be very big.
        >
        > It wouldn't have to be the raw data. But something that allows
        > tracking of progress over a period of weeks.

        Then we would see that the lama gets best scores and nothing else.
        There would not be any chance to evaluate the data in other ways.

        > Could there be a
        > "score" or average that could be loaded to a PC?

        Tracking the progress with few score data would be enough
        for biofeedback sessions and could be perhaps an alternative
        method for saving the sessions.

        Regards,

        Joerg
      • Rob Sacks
        Hello Jörg, ... I used the little Character Map program. From now on I ll just copy and paste. (Unless you prefer oe ?) ... Yes, I think you re right. I
        Message 3 of 16 , Dec 1, 2000
          Hello Jörg,

          > A little trick with the ALT-Key ?

          I used the little Character Map program. From now on
          I'll just copy and paste. (Unless you prefer "oe"?)

          > If you provide a dialog to store only channels that are used,
          > the amount of data will be quite moderate for modern PCs.

          Yes, I think you're right.

          I think it would be best to save the voltage values
          in a machine-independent format. This requires less
          code and therefore fewer opportunities for bugs. It also
          makes it easy to guarantee that all future versions of the program
          can read all data files made by earlier versions.

          Since we can't be sure how many digits will be required
          to express the precision of future machines, the header
          will probably need a field describing the format of
          each number.

          I could, I suppose, bit-pack the voltages -- in other words,
          if there are only 1024 possible voltages, each number would
          occupy 10 bits in the file instead of 16. However, the file
          would still benefit from zipping (because its length could be
          reduced further by run-length encoding) so maybe it's not
          worth the trouble.

          Rob
        • Joerg Hansmann
          Hi Rob, ... From: Rob Sacks To: buildcheapeeg Sent: Friday, December 01, 2000 6:09 PM Subject: Re:
          Message 4 of 16 , Dec 2, 2000
            Hi Rob,

            ----- Original Message -----
            From: Rob Sacks <editor@...>
            To: buildcheapeeg <buildcheapeeg@egroups.com>
            Sent: Friday, December 01, 2000 6:09 PM
            Subject: Re: [buildcheapeeg] Re: hi folks


            > Hello Jörg,
            >
            > > A little trick with the ALT-Key ?
            >
            > I used the little Character Map program. From now on
            > I'll just copy and paste. (Unless you prefer "oe"?)

            "ö" is ok. ;-)
            I have used "oe" for compatibility with 7 bit mail systems.
            On modern systems "ö" should work fine.

            ...
            > I think it would be best to save the voltage values
            > in a machine-independent format.

            A machine-independent format is a good idea.
            However I do not like voltage values very much, because
            they have rounding errors and produce additional overhead
            compared to raw AD-values.
            e.g if the gain of the RS232EEG is adjusted, so that
            full range is from -200uV(AD=0) to +200uV(AD=1023) ,
            one bin would be 400uV/1024 = 0.390625uV.

            What number format would you choose for this situation ?
            float ? Or some fixed point format ?
            What if later machines have 16 bit resolution or even 20 bit ?

            > This requires less
            > code and therefore fewer opportunities for bugs. It also
            > makes it easy to guarantee that all future versions of the program
            > can read all data files made by earlier versions.
            >
            > Since we can't be sure how many digits will be required
            > to express the precision of future machines, the header
            > will probably need a field describing the format of
            > each number.

            Something like this ?:
            In the header for each channel (including digital channels) is defined
            how many bits (n) the channel has plus 2 floating point voltages for
            AD=0 and AD=(2^n)-1.

            In the data section, each channel would be stored in raw AD-values
            using as much bytes as the number of bits (n) requires.

            A format as described above would provide relative efficient
            memory usage and could be expanded to as much bits per channel
            as required. It would be even possible to have different bit numbers
            and calibrations for each channel.


            > I could, I suppose, bit-pack the voltages -- in other words,
            > if there are only 1024 possible voltages, each number would
            > occupy 10 bits in the file instead of 16. However, the file
            > would still benefit from zipping (because its length could be
            > reduced further by run-length encoding) so maybe it's not
            > worth the trouble.

            If disk space becomes an issue, it would probably be advantageous
            to implement a good data-compressor/expander algorithm. (I assume
            the alogrithms for lha,arc, zip etc. are available in the web )

            Regards ,

            Jörg
          • yaniv_vi@yahoo.com
            how important is an fda approval do you think. why? from what aspects we should be carefull? an long detailed answer from you as an neurofeedback expert would
            Message 5 of 16 , Dec 6, 2000
              how important is an fda approval do you think.
              why? from what aspects we should be carefull?
              an long detailed answer from you as an neurofeedback expert
              would be very helpfull.
              and generaly can you help as in the design ?
              gives tips , and stuff that's important?
              how you would like to see our end result ?
              are we doing any mistakes to your opinion ?

              sincerly , yaniv v

              --- In buildcheapeeg@egroups.com, "Rob K." <smile@c...> wrote:
              > To the best of my knowledge, the Waverider is NOT FDA registered.
              >
              > THe brainmaster is.
              >
              > Rob Kall, M.Ed
              > 215-504-1700 fax 215-860-5374
              > 211 N. Sycamore St. Newtown, PA 18940
              > www.futurehealth.org "The most informative biofeedback site on the
              web."
              > Jim Robbins, Symphony in The Brain
              > 9th Annual Winter Brain 2001 Meeting Feb 2-6, Miami
              > 4th Annual Optimal Functioning & Positive Psychology Meeting, Feb.
              1-2,
              > Miami
              > www.positivepsychology.net free chapters from The Happiness Response
              >
              > "In India when we meet and part we often say,
              > "Namaste," which means...
              > I honor the place in you where the entire universe resides,
              > I honor the place in you of love, of light, of truth, of peace.
              > I honor the place within you where if you are in that place in you
              > and I am in that place in me,
              > there is only one of us.
              > Namaste` "
              > -Ram Dass
            • yaniv_vi@yahoo.com
              ... meditating ... use zip and i think the file won t be very big . you should check it . nd if not - there s probably a special alghorthm for brain wave
              Message 6 of 16 , Dec 7, 2000
                --- In buildcheapeeg@egroups.com, "Rob Sacks" <editor@r...> wrote:
                > Joerg,
                >
                > (If I write your name this way, Jörg, does it work?)
                >
                > > Sounds nice. I am really interested in samples of brainwaves of a
                meditating
                > > lama. Perhaps Rob could add the feature of recording / viewing
                > > eeg-data files.
                >
                > What should we put in the files? If we store all
                > the data (the raw serial input or the microvoltages)
                > the files will be very big.

                use zip and i think the file won't be very big .
                you should check it .
                nd if not - there's probably a special alghorthm for brain wave
                compression - but don't think well need it .


                >
                > Rob
              • yaniv_vi@yahoo.com
                ... just ... infra ... TSOP17.pdf ... i think let s say 20 cm is enough and even a lot more then we need. we just need to think about the comofrtablity of the
                Message 7 of 16 , Dec 7, 2000
                  --- In buildcheapeeg@egroups.com, "Joerg Hansmann" <jhansmann@g...>
                  wrote:
                  > Hi yaniv,
                  >
                  > ----- Original Message -----
                  > From: <yaniv_vi@y...>
                  > To: <buildcheapeeg@egroups.com>
                  > Sent: Thursday, November 30, 2000 9:13 AM
                  > Subject: [buildcheapeeg] Re: hi folks
                  >
                  >
                  > > if you want to make it simple - it doesn't have to be true irda .
                  > > the first version of the desing could be consisted of 2 boxes :
                  > > one is the eeg with simplest infrared comm , and the other is
                  just
                  > > little thing that connects to parallel port/serial port , with
                  infra
                  > > red com .
                  >
                  > If you think of IR-receiver ICs like the TSOP17xx series, you should
                  > consider, that maximum data rate is 2400 baud (from Vishay
                  TSOP17.pdf
                  > datasheet ). That is far below the 57600 baud required by RS232EEG.
                  >
                  > Using a simple PIN-IR-receiver diode will work only over very short
                  > distances (some cm).
                  > BTW. what distance will we need ?

                  i think let's say 20 cm is enough and even a lot more then we need.
                  we just need to think about the comofrtablity of the user .
                  and also choose ir comm with apereture angle wide enough.
                  so the rx and tcx won't have to be exactly infront of each other .

                  >
                  > > i don't think that would higher the price much.
                  > > and the design is basicly already there (on the net).
                  >
                  > A complete schematic for an irda transceiver that can be connected
                  > to RS232 and can handle up to 115200 baud is described here:
                  > http://www.vishay.com/pdf/toim3232.pdf
                  > However it uses two SMD chips and I don't know, how easy or
                  difficult
                  > soldering will be.

                  send me the package name and description . don't send pdf - only
                  std formats like html - bmp - jpg and same - cause i can't read
                  them - i'll have to nstall a special software .
                  but basicly - the soldering shouldn't be hard .
                  i solder some smd chips , and i'm not really good with solder .
                  jhust practice a lkittle before - with lows cost chips and all will
                  be fine .




                  >
                  > > just for the 1st version i think it'll be good.
                  > > after the first version if all we'll be o.k. then i'll think we
                  could
                  > > work on better version easier - because we'll probably have more
                  > > people .
                  > > but maybe full irda is better , i don't know ?
                  > > > > ) and
                  > > > > with right box ( plastik with metal foil) we'll be safe enough
                  > > >
                  > > > The FDA probably wont think so before they have approved the
                  device.
                  > > >
                  > >
                  > > there's a eeg device called waverider - sells for $950 without
                  fda
                  > > approval -
                  >
                  > Perhaps they have a good lawyer or a good product liability
                  insurance.

                  we should have lawyer what's about it?

                  >
                  > > and it's presented in futurehealth site - a very
                  > > respectable site for this things .
                  > > and another thing - i agree we should check it with some b.f.
                  > > practicioner maybe - or somebody that will check .
                  > > maybe somebody should check what it takes to run throught an
                  > > fda - and how much it'll cost for a gruop of volunteers ,
                  > > and if it's possible to be done by a group of volunteers ?
                  > > but i don't really think fda approval is a must .
                  > > i just thjink we should really check it with someone experienced
                  > > before getting it to market - maybe some b.f. practicioner would
                  > > volunteer -if we'l find one .
                  >
                  > ...
                  > [patents]
                  > > > The overall principle is the same.
                  > >
                  > > there have been numerous designes basicly the same .
                  > > i don't really think there's a problem ,but i guess it's better
                  to
                  > > check , and as i seen in our group we may have contacts to a
                  lawyer -
                  > > so it'll be o.k.
                  > ...
                  >
                  > > a little question joerg :
                  > > assuming i want to be the first beta tester - let's say even of
                  the
                  > > version without irda - just a good version for portable pc (no
                  need
                  > > of isolation)
                  >
                  > The current prototype _is_ isolated with optoisolators. (The BM also
                  > uses optoisolators for RS232).

                  it's better

                  >
                  > > would like to build one board and send it to me - i'll pay the
                  > > costs ? how much are the costs ?
                  >
                  > Material cost (without casing) is about 200,- DM.
                  > shipping and insurance = ? (depends on the destination)

                  basicly it should be like $40 up to 5 kg , $63 up to 10 kg ,
                  airmail . but you tell me how much .

                  >
                  > Can you make money transfer to a german bank ?
                  > (When I tried to make a transfer from Germany to USA,
                  > I found out, that the banking fees are extremely high)

                  i'll fgure it out .

                  >
                  > Do you need casing or the raw assembled pcb ?
                  > What about RS232 cable ? What length ?

                  casing yes .
                  long cable is always better .
                  do you think 2 meter would have no problems as rs232?


                  >
                  > What about power supply ?
                  > If your laptop had a gameport-connector, +5V from your laptop
                  > could be used. However I don't know how much noise
                  > is on that line.
                  > Do you have the possibility to get +12V DC from your laptop ?
                  > In this case the built in 7805 regulator could be used and line
                  noise
                  > would not be a problem.

                  totaly battery based .
                  like 6 or 5 --> 1.5v batteries depending on your regulator .


                  > What connectors/sockets for electrodes are required ?
                  > (banana sockets ? (in german : Bananenbuchse))
                  > or better BNC or cinch ?
                  > I don't know the standard for eeg-electrodes...
                  >
                  > BTW. Where can I get good and low-priced EEG-electrodes ?
                  >

                  don't really much about this .
                  i think we should define the cponnector fpor the machine and test\
                  it with std. electrodes .
                  this type i would like to have .
                  i think 'll send a message to the group about electrodes ?


                  > > when it'll be ready stable enough
                  > > version of the h.w. - tested and tested in really measuring
                  > > brainwaves ?
                  >
                  > I have sampled real brainwaves with the RS232EEG and tried
                  > some alpha-feedback with Rob's Software.
                  >
                  > What are your demands for stability and tested in detail ?
                  i just want t to work with no problems here ?
                  how much time you have tested your last version ?
                  which tests?
                  wee should think on some pre beta tests


                  >
                  > > the software i can always download from the net , so no problem .
                  > >
                  > > basicly my problem that my friend in israel that was supoosed to
                  > > build brainmaster and send it to me - hasn't got the time - and
                  also
                  > > not very serious about it , so basicly i think he won't build it .
                  > >
                  > > i'm intend to find a buddhist lama here that would like to work
                  with
                  > > me using eeg and other buddhist techniques , so it may be also
                  good
                  > > for the public realtions of the project ?
                  >
                  > Sounds nice. I am really interested in samples of brainwaves of a
                  meditating
                  > lama. Perhaps Rob could add the feature of recording / viewing
                  > eeg-data files.
                  cool idea

                  >
                  >
                  > regards
                  >
                  > Joerg
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