From: frans smith (f.smith_at_c...)
Date: 2001-06-15 16:35:50
Hi lovass,
The file basic hal/ 80C32 is corrupted (zip)
Afther downloading i could not unzip the file
hal-plus.
The other file hal-program is okay.
regards
Frans
----- Original Message -----
From: "Lovass Laszlo" <prochess_at_e...>
To: <buildcheapeeg_at_yahoogroups.com>
Sent: Monday, May 28, 2001 9:27 PM
Subject: [buildcheapeeg] Re: Is Sound Card feasible?
> Hi,
>
> I read list messages for more than a month. As I am also interested in EEG
> development, most of the ideas have triggered my attention.
>
> I have modified HAL-4 and extended its features, started to develop some
SW,
> see my page:
>
> www.extra.hu/lovass/biofeedback.htm
>
> However, I have serious technical doubts about the 'cheap' soundcard based
> solution, agreeing with the quoted topic article.
>
> Maybe not-so-cheap after complicated VCO/modulation, hard to extend,
> distorsion possibilities - comparing to standard RS232 solutions.
> Not talking about the 'soundcard hacking', which is the worst compromise,
> source of unexpected problems, seems like a salute to Murphy's Laws. ;)))
>
> I think about two possible basic concepts:
>
> 1. The cheapest way could be a (1-2 channel) 'brainwave band detector',
> could work even without PC. Just needs some well designed band-pass
> filters - after amplification - for alpha and theta to some LEDs or simple
> sound (rectangle) generator(s) for acoustic feedback.
>
> Of course, these levels can also be opto-coupled to gameport as amplitudes
> of brainwave bands (4-5 bits would suffice).
>
> One cannot expect precise values, but simple HW, SW and still works for
> basic purposes, el-cheapo for the masses ;))).
>
> 2. Yet cheap to pro equipment, but even scientifically usable, 2..6
channel,
> IRDA or RS232 connected unit, 12-bits ADC integrated with the controller
> (hoping RS232 is not the bottleneck, maybe data compression? ;), band
filter
> for 50, 60 Hz or low pass filter from 1 Hz upto 43-45 Hz and steep cut of
> higher freqs.
>
> 40 Hz freqs could have major importance these days, see / search for
Rodolfo
> Llinas research (in NY), that's why I suggest to keep this band.
>
> I also think of circuit (small, low-consumption, SMD mounted) and
electrodes
> mechanically integrated into one unit, to an IRDA connected
> (battery-powered) helmet (like Borg from Star Trek ;))).
>
> To give some helmet ideas, see:
>
> http://www.east3.com/technology_thoughtcaster.html
>
> Maybe it's late for such a brainstorming in this project phase, just my
> opinions.
>
> Regards,
>
> Lovass Laszlo
>
>
>
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This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:31 BST