openeeg-list

[Openeeg-list] Has anyone got the Olimex EEG-SMT to work for them?

[Andrew H. <aho...@rp...>]

I recently bought the Olimex EEG-SMT, but am having difficulty making it
work.

   - Their installation instructions call for modifications to a driver in
   a directory that does not exist on my MS-Windows XT machine (an "Other
   Devices" directory in control panel->System->Hardware->device manager).
   - A normal USB port does not appear to provide enough power to run the
   device, though they do not say so in their specs. They recommended that I
   purchase a powered USB hub, and I did, but this has not fully solved the
   problem.
   - They also recommended that I buy a "high quality" USB cable. I bought
   a new cable, but when I asked at the store if it was "high quality," no one
   knew what I was talking about. *Are* there special high quality USB
   cables? If so, how does one find and identify them?
   - I switched at their suggestion from BioExplorer to BrainBay, one of
   the two programs with which they have tested the device. (BioExplorer has
   an OpenEEG driver, and I see that there are people on this list who have
   used it successfully with home-built machines). Using BrainBay, the EEG-SMT
   produced things that looked like brainwaves. (Using BioExplorer, it
   produced waves that looked like bar code - closely spaced vertical lines
   that occupied the entire EEG screen). However, I did not get increased
   alpha with eyes closed, which I have found in the past to be diagnostic of
   a bad connection. I then removed the electrodes from my head, and found
   that I was continuing to get an unchanged waveform on the scope and the
   same range of variation in the bands I was measuring, SMR and theta. I
   concluded that I was only seeing noise, despite the active electrodes.

So I am wondering if anyone has purchased the Olimex EEG-SMT and verified
that it is producing good brainwave data for them, waveforms that vary
appropriately with mental state and do not continue with no scalp
connection. Before I spend a lot more time trying to debug the
installation, it would be reassuring to know that there is not some
hardware or software problem that makes this machine fail consistently for
other people. Alternatively, if anyone has encountered and overcome any of
the problems I describe above, I'd love to hear about that too.

Thanks in advance for any help you can offer.

Peace & Joy, andrewH

Re: [Openeeg-list] Has anyone got the Olimex EEG-SMT to work for them?

[Niels S. <nie...@gm...>]

Hi Andrew,

See my answers between your questions.

On Wed, May 23, 2012 at 5:54 PM, Andrew Hoerner <aho...@rp...> wrote:
> I recently bought the Olimex EEG-SMT, but am having difficulty making it
> work.
> Their installation instructions call for modifications to a driver in a
> directory that does not exist on my MS-Windows XT machine (an "Other
> Devices" directory in control panel->System->Hardware->device manager).

You've downloaded this package from FTDI website: CDM20814_WHQL_Certified.zip?.

> A normal USB port does not appear to provide enough power to run the device,
> though they do not say so in their specs. They recommended that I purchase a
> powered USB hub, and I did, but this has not fully solved the problem.

That's strange. I've hooked up the device with several laptops and
powering was never an issue.

> They also recommended that I buy a "high quality" USB cable. I bought a new
> cable, but when I asked at the store if it was "high quality," no one knew
> what I was talking about. Are there special high quality USB cables? If so,
> how does one find and identify them?

Use one with gold plated plugs like this one:

https://www.4u-tech.nl/index.php?item=hq-silver-series-usb-a-b-aansluitkabel-5m&action=article&aid=48986&lang=NL
It made a huge difference in signal quality!

> I switched at their suggestion from BioExplorer to BrainBay, one of the two
> programs with which they have tested the device. (BioExplorer has an OpenEEG
> driver, and I see that there are people on this list who have used it
> successfully with home-built machines). Using BrainBay, the EEG-SMT produced
> things that looked like brainwaves. (Using BioExplorer, it produced waves
> that looked like bar code - closely spaced vertical lines that occupied the
> entire EEG screen). However, I did not get increased alpha with eyes closed,
> which I have found in the past to be diagnostic of a bad connection. I then
> removed the electrodes from my head, and found that I was continuing to get
> an unchanged waveform on the scope and the same range of variation in the
> bands I was measuring, SMR and theta. I concluded that I was only seeing
> noise, despite the active electrodes.
>
I suggest you use Electric guru first to test your device. It's simple
and straightforward programm to show the raw signal coming from the
device. You should get a signal that responds to grinding the the
teeth or blinking the eye. Also the amplitude will increase when you
close your eyes. Note the only place to use the active electrodes
without any paste is on the forehead.

I don't know if this will work but I've attached a picture showing
some clean eeg reading with the device.

> So I am wondering if anyone has purchased the Olimex EEG-SMT and verified
> that it is producing good brainwave data for them, waveforms that vary
> appropriately with mental state and do not continue with no scalp
> connection. Before I spend a lot more time trying to debug the installation,
> it would be reassuring to know that there is not some hardware or software
> problem that makes this machine fail consistently for other people.
> Alternatively, if anyone has encountered and overcome any of the problems I
> describe above, I'd love to hear about that too.

I've overcome a lot of problems with the device too but I have got it
to work. Have not done any neurofeedback training with it yet but it
shows a good enough quality signal for it. I'm going to use it with
active electrodes which have saline felt patches attached so I can
measure the eeg signal at other scalp locations as well.

Kind regards,

Niels

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