Re: A Non-Review of the Olimex EEG-SMT

You are missing the point.

This device has been recommended by list members, and from what I understand, is predicated upon the openEEG design spec.

I went to the effort of a) asking for the safety isolation specs of the openEEG electrodes and associated hardware, the request of went unanswered by any list member; yet b) still purchased the unit for testing and experimentation.

The low cost of the EEG-SMT means nothing if I can't actually purchase one, and Olimex has now tied up the entire purchase amount (including shipping fees that were calculated for a destination in the USA) for at least a week in the Paypal refund process, despite the fact that the payment was wired directly to whomever AND adjusted for conversion from the euro to dollar.

Because I wired the converted purchase amount instead of using a drop down Euro button in Paypal.

Absurd. No thanks.


From: Stefan Jung [mailto:[email protected]]
Sent: Wednesday, November 07, 2012 05:03 AM
To: [email protected] <[email protected]>
Subject: Re: [Openeeg-list] A Non-Review of the Olimex EEG-SMT

Gregory

The good folks that developed the openEEG project have arrived at their destination 7 or so years ago and have left ship!

I have written a mini-review of available amps a few months ago and you can read it here:
http://openvibe.inria.fr/forum/viewtopic.php?f=11&t=526

I stay in South Africa and find trans-border exchange also very frustrating, especially the huge amounts of shipping and conversion charges that are charged.  But that is life.  Fact is, if an American Co would be selling a device comparable to SMT-EEG, it would cost 5x as much!  So either buy an Australian Pendant, a Bulgarian SMT-EEG, Bulgarian Optima2 or an Argentinian Focus, or pay substancially more for J&J, BrainMaster, etc.

SMT-EEG is save.  The DC/DC converter is rated at 3000VDC and the TI capacitive-based digital isolator is rated at 4000Vpeak.  Having said that, I personally would not use such a device with an electric storm brewing, and even less, if lighting comes thundering down at my front door.  But that is a personal view only.  Others would disagree.  I just like playing safe. (I have already pointed this view, regarding lightening, out on this forum, only a few months ago.)

You should realise that there is a lot of crap being sold all over.  I regard the SMT-EEG a 500% better designed product than the silly Pendant - just as an example.  The Pendant has it's electrode inputs connected STRAIGHT to the instrumentation amplifier's input pins.  There is no static isolation and there is no RF filter(!)  I, as a professional EE, I want to puke when I see something like that.  The Pendants are build into some MP3 player's plastic enclosure, a badly fitting one, for that.  I think some Chinese manuf. made these casings and they where most likely rejected by the Chinese MP3 player manuf.  And then sold as dirt cheap scrap to Neurobics.  The double sided PCB is just as bad.  The soldering looks like bird droppings, there is no proper silk-screen, the whole thing reminds you of the build quality of a cheap Chinese toy.  Yes, there are many, many Pendants in the field, in the hands of both home- and full-time neurofeedback partitioners.  Most seem happy enough with the performance of these devices (judging by my many years readings of the braintrainer forum).  Seeing the hardware, I am surprised.  I would have expected it's performance to be equilivant to dog poop.

Let's take another example.  You can pay over $2000 for a 4-channel QDS Excalibur - I guess you could get them marked down these days... but the official list price was over $2K.  Read my comments on the above mentioned link.  The Excalibur's build quality is reasonably good... BUT what is the use in providing electrical isolation with opto-couplers rated at 3000V or whatever, and then criss-crossing the isolated and non-isolated hookup wires.  Cheap PVC wire is normally rated at 300V.  So if iso- and non-iso circuit wires touch each other, you end up with a rated isolation of 600V(!)  What a dense schmuck does that?  And this is for an amplifier costing over $2000!  What they SHOULD have done is to neatly and carefully route those wires, so that the two sides have a fair distance between them.  But that is not surprising, comming from my "zero nV" noise friend, Dr. D. Rocatti (QDS proprietor), who advised forum people to rap their EEG-amplifiers in tin-foil, so as to reduce the noise.  (I guess then you get less than zero noise?)  Fact is - he made this statement generic, not amplifier specific.  The tin-foil will act as a nice conductive path between the DIN-input connectors and the non-isolated RS232/USB connector on the other side of the EEG box, potentially by-passing any isolation inside the box.  Go figure!!

I would LOVE to receive high res colour pictures of the inside guts of any other amplifiers.  You normally get what you pay for.  In case of SMT-EEG you get much more than what you pay for.  Do you get what you pay for from a J&J, BrainMaster, ProComp, NeuroAmp, Nexus,Nexstim, gTec, etc.?  I expect them to be good, albeit over priced.  But who knows, I might even find fault with devices in that sort of price bracket.  You ASSUME that a BMW must be better than a KIA.  Well my BMW's fuel gauge doesn't even work properly.  New BMWs don't have a oil dipstick.  Must I now trust the electronic oil level sensor to tell me that my oil is OK, Mmm?  And replace the silly sensor for an arm and a leg price tag, if it misbehaves?  The whole world went nuts.

Trust No one.  Trust nothing.  Everyone is taking the consumer for a ride (of his life), ha!

Regards
Stefan

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