poor electrode connections

SUSH123SUSH123 india
edited January 2018 in Electrodes
HI,
we were working with the Cyton board . We made connections as shown in the tutorial.
But we are not getting signal correctly using OPENBCI GUI .
We connected the remaining electrodes not shown in the tutorial to the remaining lower pins.
could u help with the positon/connection of these elctrodes to the Board.
Also we use earlobe(white) and Cz(black) as reference.(are these right)?
where are we suppose to connect the black wire connected to the bias pin(is it reference)?

Comments

  • SUSH123SUSH123 india
    Hi,
    We connect red ,purple ,green and yellow to the bottom pins and black and white for bias and reference.
    however on OpenBCI we are also getting signals on orange elctrode that is not connected(just noise) ,is there some mistake we are making?
  • wjcroftwjcroft Mount Shasta, CA
    (1) only connect electrodes to the board which are connected to skin on the other end. Unconnected wires will act as antennas for noise. Or pickup signals from adjacent wires.

    (2) The tutorial shows reference on one ear and bias on the other. You 'can' use Cz as reference if you want.

    (3) a common test of your wires and signals, is to connect all three (channel, reference, bias) together with a blob of paste. This should result in a signal close to zero microvolts.
  • SUSH123SUSH123 india
    Thankyou.
    Our electrodes have seem to lost colour in the process of cleaning. 
    Could this lead to some problem in recording signals???
  • wjcroftwjcroft Mount Shasta, CA
    The gold plated cups have a very thin plate. It's possible to clean without rubbing.


    If the plating chips or wears off, then you can possibly have some galvanic effect from the metal underneath the gold. (Two metals and salt makes a battery.)

  • swatiswati india
    Is there some way to avoid galvanic effect and get good eeg signals using the partially corroded(the plating being worn off and the electrodes have lost original colour and have become dull) gold cup electrodes
  • wjcroftwjcroft Mount Shasta, CA
    If you do some searching on the web or with India suppliers, you should be able to find new electrodes for a few dollars each. The gold type have this disadvantage. You can also get solid silver or solid tin, which do not "wear out" the plated coating -- because they are solid metal, not plated.
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