From: Lovass Laszlo (prochess_at_e...)
Date: 2001-05-28 20:27:27
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
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:30 BST