EEG-SMT Lots of noise

Started by Crowstream, December 06, 2013, 06:27:48 pm

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Crowstream

Hi!

I just got the EEG-SMT and I am trying to get it to work. I am using a passive electrode for the DRL channel and 4 active electrodes for channels 1 and 2.

I can get signals from it in Electric Guru and Brain Bay for both channels.
The problem is that I am getting a lot of noise, I have done some testing and here is an example of what happens:

In this picture I have the passive electrode connected to my ear, the 4 active electrodes on my forehead set up symmetrically like the instructions in the manual.

First you can see the signal is extremely noisy on both channels, at 0:00:38 I touch my computer which dramatically effects the reading, this is repeatable, if I stop touching the computer massive noise returns.


In this picture I disconnected the 4 active electrodes but still have the passive connected to my ear, as you can see even with no electrodes I get a lot of noise.

Now I have also tested some other things, like just using 1 channel at a time (still with DRL connected to my ear) using different sets of electrodes. Both channel 1 and 2 still seem to be noisy when I do this, even with different sets up electrodes, moving the electrodes to different positions, using different computers and switching between brainbay and electric guru.

I still cant seem to get any useable signal doing this.

Any help is greatly appreciated!

Thanks!

LubOlimex

Hey there,

The readings are not normal. These readings seem as if the DRL is not connected or held properly at all. Try to hold it firmly in your hand/palm. Make sure the passive electrode (the one that lacks IC on its back) is connected to the DRL.

Can you upload a picture of a reading under Electric Guru of the device with NO electrodes connected? It should be a straight line.

Best regards,
Lub/OLIMEX
Technical support and documentation manager at Olimex

Crowstream

I tried holding the passive DRL electrode in my hand and it does not seem to make any difference.

Using no electrodes, I still get a signal, like this:

LubOlimex

Hey Crowstream,

Seems like a hardware problem with channel 1. This is either soldering flux not being properly washed off the board OR the soldering on one of the audio connectors has broken.

Please contact support@olimex.com and request RMA. The warranty conditions are mentioned here:https://www.olimex.com/wiki/GTC#Warranty You might quote my advice for a return so the e-mail is processed faster. My advice is to send the electrodes back for inspection also. Testing the whole setup is the better method.

Best regards,
Lub/OLIMEX
Technical support and documentation manager at Olimex