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217Re: Hardware status (cheapeeg)

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  • e_e_ling@hotmail.com
    Apr 1, 2001

      Thanks for your detailed reply, I am now using your information for
      the news page.

      Does IrDA mean the eeg can only be used with a notebook pc? If that
      is the case, I think it would really restrict public interest in the
      system as most people have desktop PCs. The brainmaster works on a
      desktop so for most desktop owners it would be cheaper to buy a
      brainmaster for their existing pc ($1000) than to buy our system and a
      new notebook ($2000?). Did I understand you correctly or can IrDA be
      used with desktops?

      I agree that we need to fulfil some kind of safety criteria, but maybe
      it doesn't have to be done immediately. As long as the eeg is safe,
      i.e. won't blow up/electrocute us, it should be ok for us each to own
      a test version for a few weeks; then we can make further improvements
      to the design and research safety standards before releasing it to the
      public... what do people think?

      As for the manufacturers of expensive EEG and the pharmaceutical
      companies... of course they won't like our cheapeeg! So yes, we have
      to be careful, but we have to remember one thing: an EEG provides
      information. It measures brainwaves. That's it. It has no effect on
      the user at all, unless that user actively engages in biofeedback
      training. I don't believe biofeedback can have any harmful
      consequences but in any case it is the user's choice, so I really
      don't think we should be worried about this.

      What are "mignon NiMH" batteries? I did a web search and all the
      matching sites were in Germany - is it a german battery? Will this be
      a problem for the rest of us?

      Finally, you mentioned you were in discussion with an electrode
      supplier. What kind of electrodes are you thinking of using? Is it
      possible to use flextrodes (from Brainmaster) which require no gel?



      > There are also people who might not like our
      > cheapeeg. (The manufacturers of expensive EEG maybe or the pharam
      industry as
      > well)

      --- In buildcheapeeg@y..., Moritz v. Buttlar <info@b...> wrote:
      > Hi !
      > I´m sending you now the current status of the hardware (the part I´m
      working on)
      > Joerg will probably do the same.
      > I´m trying now to implement IrDA. It´s quite difficult and I´m not
      sure yet if
      > it will work and whether it´s a good idea in the first place.
      > The alternative would be to use very good optocouplers and connect
      the EEG by
      > cable to the computer. This is a safety issue. If we use IrDA nobody
      can make
      > serious mistakes by connecting something wrongly. Many small
      notebook computers
      > are equipped with IrDA connectors, but many desktop PC´s aren´t.
      > We have to find out what the people want :)
      > And also what kind of safety norm we have to fulfill if the eeg
      should ever be
      > manufactured and sold. We really should try to find somebody who has
      > about all the legal issues we face with our project.
      > What do we have to write on the website in order to make sure that
      we don´t
      > get into trouble if somebody gets hurt when trying to build the
      cheapeeg from
      > our plans ? Or if somebody claims that he got schizophrenia by using
      our device
      > ?
      > I don´t think it´ll ever happen but there are quite ignorant people
      > on this planet....
      > There are also people who might not like our
      > cheapeeg. (The manufacturers of expensive EEG maybe or the pharam
      industry as
      > well)
      > I´m also trying to add a very good AD converter featuring 20bit /
      > (ADS1250). This allows a better dynamic range. The ADC also includes
      a digitally
      > programmable amplifier stage. Therefore we can control the
      amplification by
      > software (no more manual adjustment necessary). It costs only 6$ and
      is one of
      > the best ADC available. I know that 20bit aren´t really necessary.
      But the
      > additional bits can be used for amplification as well (just shift
      the result to
      > the left and you get an amplification by 2). Our design probably
      won´t be good
      > enough to get 20bit resolution, but maybe 18bit-16bit.
      > Further changes to the current design:
      > - battery supply (4 mignon NiMH batteries), no more DC/DC converter
      that brings
      > noise and is expensive and has only 1000V isolation. This will allow
      about 8hrs
      > continual operation.
      > - New microcontroller: Ubicom (former Scenix) 50Mips
      microcontroller. Costs the
      > same as the Atmel and IrDA stack is available for download from
      Ubicom. That´s
      > why I´m quite sure the IrDA part will work sometime :). It´s 5 times
      faster than
      > the Atmel microcontroller.
      > Right now I´m working on a CNC (computer numerical control) machine
      which can
      > automaticly manufacture printed circuit boards. It´s controlled by
      my PC.
      > Therefore I´ll be able to design the board on my PC and then
      manufacture it
      > automatically.
      > Software: IMHO all the software designed for the EEG should be
      > Gnu-public-licensed. Only if we have a complete open software source
      > people will start writing their own improvements for the software.
      > It would be good if we had something like the Gnu-license for the
      hardware part
      > as well.
      > The prototype by Joerg that´s already working features:
      > - RS232 connection using opto-isolation
      > - 2 channels / 10 bit (using the µC-internal ADC)
      > - works with PC-Software by Rob Sacks
      > - Power supply with DC/DC converter
      > - it works :) !!!
      > The new philosophy is:
      > We want to separate the analog and digital part. This will allow
      enhancement of
      > the analog/digital parts separately without the need to redesign
      the whole
      > system.
      > Joerg developed the state machine for EEG/PC communication. This
      > should also be published on the website. It allows programmers to
      > with our device.
      > If you want me to, I can buy the website. You can send me some bucks
      by post
      > if you want to chip in. Regarding the name: let´s start a new vote.
      Is it
      > possible to allow 2 votes for everybody ?
      > Maybe Joerg can send some photographs of his design. Maybe we could
      > a to-do list on the website to recruit people ? And a list of the
      > already involoved with email-addresses and a description of what
      they are doing
      > ?
      > Write me if you want more information about the hardware design.
      > Moritz
      > --
      > Baltic Microsolutions / Flash Microcontroller Custom-Development
      > http://www.baltic-microsolutions.de
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