From: sleeper75se_at_yahoo.se
Date: 2001-12-01 09:21:26
--- In buildcheapeeg_at_yahoogroups.com, Doug Sutherland <wearable_at_earthlink.net> wrote:
> hehehehe. I've been trying to sell the idea to Jim of
> ditching HC11 and moving over to Atmel AVR.
:-)
Fortunately, it's quite easy to make that kind of change. It's like
if you know how to drive a Volvo, you can probably handle a Ford as
well...
> Questions:
I think Moritz is the right person to answer your questions, but I
can answer the first one.
> 1) What is the frequency band width of the current design?
(Checking the schematics) It appears to be 5th order 75Hz filter
sitting there.
> Ah yes, that is Rob's work, I spoke with him on the
> telephone some time ago about this stuff. He has delved
> pretty deeply into spectral analysis. I wish I could
> hook a parallel cable to his mind and load all of his
> spectral analysis data into my brain. Hey Rob, do you
> have a DB25 port on your mind? USB? Firewire?
Well, you know... researchers are trying to connect neurons to
integrated circuits, so one of these days... :-)
> This is where most of thee hard work lies. I am a
> software guy. How can I get myself up and running with
> the current design? Can it be breadboarded? Is there
> any software for the PC side yet?
If we design a simulator first, then we wouldn't need the hardware.
Here's a proposal: A program that allows the user to draw (using the
mouse) a frequency curve, then transforms it into a FIR-filter by
using the inverse fourier transform. Apply white noise to the FIR-
filter and we have a simulated EEG-signal.
> Interesting. I wish I knew how to build those active
> electrodes described on the Biosemi site ...
Do you mean this?
http://www.biosemi.com/publications/artikel1.htm
I've uploaded my attempt to reproduce them. Check out the files-
section (hardware).
/Andreas
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