From: JBilderback (jiva_at_humboldt1.com)
Date: 2001-05-10 18:20:22
> From: Rob Kall <smile_at_compuserve.com>
> Subject: Sound Card
>
> Message text written by INTERNET:buildcheapeeg_at_yahoogroups.com
> > But if the idea is to come out with CHEAP
> eeg, the utility of sound card cannot be overlooked. <
>
> One major obstacle to overcome is safe optical isolation of the power inthe
> computer and the electrodes on the head.
>
I don't think this is an issue ... the card would require a preamp of some
sort ... a working (?) design has been posted earlier to the list with
optical isolation.
The problems that I'm aware of are:
1) the input section of all cards has a dc blocking cap that cuts off
signals below about 20hz. This apparently can be modified ... what the
ultimate pass frequency might be I don't know.
2) due to the variation in soundcards, identifying and modifying a specific
card might be desirable/necessary. future changes in chipsets would require
software upgrades (large or small)
3) much more work is passed off to the software people, since all of the
smarts have been removed from the "black box"
4) Rob's software won't work "as is" (near as i can tell) since it expects
input via serial port.
(don't know if the signal gathering module could fake this)
(or if Rob might incorporate said "module" in his software)
5) Nobody has put a price on the current project. If it can be kept in
the couple hundred $$ (US) range I'd imagine nearly everybody will byte
at it. OTOH ... it seems very unlikely a manufactured unit could be made
for anywhere near that cost and it would be "kit" form.
Which leads to ... a preamp/ soundcard combo is likely to be MUCH cheaper.
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:29 BST