From: Jim Peters (jim_at_uazu.net)
Date: 2001-12-25 09:21:12
Jim Meissner wrote:
> > Also, there are much better ways of getting the data from the EEG to
> > the computer via the sound card line-in than this, for instance using
> > amplitude-modulation of a carrier.
>
> Actually an FM modulated carrier is much less prone to noise and
> interference.
I'm not talking about using radio communication. I was talking about
using AM to get our low-low-frequency signals down a wire to a sound
card input, given that the sound card would probably filter out
anything below 20Hz. The amplitude modulation would take it well
above that, and through the barrier.
I think I can see how to convert an amplitude modulated signal back to
the original signal without too much difficulty in software. However,
I'm not too clear on how to decode FM in software. If this really is
a better solution, then fine.
> I built a wireless EEG setup using a baseball cap with electrodes
> mounted on the sweatband and the amplifier and transmitter on the
> top of the head inside the cap. The power was 4 AA batteries. It
> was possible to do biofeedback listening to your brain on the FM
> stereo.
I keep meaning to ask how your "listening to the brain" hardware
worked. As far as I know you can't do the kind of pitch-shift I'm
attempting using electronics. So what kind of modulation did you do
to make the brain-wave signals audible ?
(Merry Christmas all, by the way!)
Jim
-- Jim Peters (_)/=\~/_(_) Uazú (_) /=\ ~/_ (_) jim@ (_) /=\ ~/_ (_) www. uazu.net (_) ____ /=\ ____ ~/_ ____ (_) uazu.net
This archive was generated by hypermail 2.1.4 : 2002-07-27 12:28:36 BST