[Noisebridge-discuss] openeeg

[Jonathan Foote]

> I'm sure there are some misconceptions about the limitations of EEG
> hardware. I'm also pretty sure that people are expressing that they want
> brain output of *any* sort. To play with the data that is easily
> available and not to build some kind of commercial whiz-bang
> application. I personally want to explore and to experiment. I'm not
> expecting to control gdb or vim with a headset. I like the idea of the
> Emotiv headset because it seems to be industrially designed for many
> heads and not just one. It sure seems to beat a flimsy headband too.

That is super. I apologize for wet-blanketing: I know enthusiasm is a
precious and is to be encouraged. However this area is very prone to
the enthusiasm->discouragement trajectory like Tracy describes, and I
can only hope that keeping expectations in line with reality might
help with that.

It's clearly not "all noise" but getting signal is a Hard Problem, and
I've seen little success with low-electrode-count approaches like
OpenEEG (though I would love to be proved wrong on that). The
technology is very straightforward (high-impedance high-gain
amplifiers) and I'm afraid I don't have any special sauce to success
other than reminding people what has been shown to work: multiple
channels (19 is standard) and medical-grade electrodes (yes, with the
conductive jelly).

> I think many people (myself included!) interested in EEG stuff probably
> don't have a good handle on all of involved concepts. Nor does everyone
> have a way to capture the data that needs to be acquired, nor do we all
> have the circuits involved in that acquisition and I'm certain that we
> haven't all done the programming for processing that data. A simple
> project may serve as a good peer learning project where we can cross
> pollinate. It's all part of some kind of boot strapping process that
> will take us to bigger things. Who knows where and what?

That's an excellent suggestion. A straightforward project might be
something like this:
(I apologize I can't take the lead on this due to a surfeit of other
quixotic endeavors):

1. Get a pool of OpenEEG cards. I would suggest starting with 8.
Maybe several people want to "adopt" one by buying a kit and we can
have a solder party. I will adopt one myself.

2. Put them all in a metal box with a solid ground. Ideally, it has RF
gasketing and nice BNC connectors for I/O.

3. Find someone with a 8-channel USB-audio interface for signal
acquisition. These are pretty common with the musician crowd. (Sample
rate is overkill, but that's OK). Anybody have one we could borrow?

4. Find some good electrodes. Sanity check each channel by detecting
heartbeats. (If we can't get those loud and clear, no point looking at
the brain's much weaker signals.)

5. Now are we ready to do EEGs. I would suggest -- nay, insist -- on a
double-blind protocol, otherwise we will see results that aren't
there. It's simply human nature. So get subject(s), over several
trials, to say, attempt achieving an alpha state, and for a control, I
don't know, read BoingBoing or something. Get a third party to
randomize the order and keep track of data labels. (Might experiment
with evoked potentials too as long as we're all set up.)

6. When you have some data, call in the geeks. I am personally expert
at Fourier analysis, and have some experience with LDA (linear
discriminant analysis) using SVD (singular value decomposition). I'd
be happy to share what I know (including open-source tools like Octave
and SciPy) and chew on the data for an evening.

7. Bootstrap from there, as this may not work at all.

> Perhaps as you seem to know lots more than many involved, you can help?
> Perhaps give a workshop on the general overview of EEG stuff? I'll show up and I'm surely not the only one!

Though I've done heartbeat detection with some success, my personal
experience building EEGs is close to zero, so I am learning too.
I'm not sure I could do a better overview than the various Wikipedia
pages. But (as you've noticed) I'm happy to pontificate and make
suggestions. Thanks for the invitation.