Modify GUI Headmap Electrode Positions / Channels

compmonkscompmonks zurich
edited February 2017 in OpenBCI_GUI
Hi all,
I am currently working with p300 and would need to rearrange the electrodes positions.
Is there a way to specifiy these from the GUI or any documentation ?

Cheers

Comments

  • compmonkscompmonks zurich
    edited February 2017
    Here are a few more precisions to my question:
    are the position of electrodes only relevant to the Headplot of the GUI?
    If yes, is there an existing text file with all positions of the Mark4 headset model?
    If no, what is to change on the board (cyton+daisy) nodes placement and the GUI?
    Thanks a lot
  • jussijaatinenjussijaatinen
    Is it possible to change default electrode locations in OpenBCI_GUI software? I would like to use center line electrodes, like Fz, Cz and Pz. Of course I can collect data normally anyway, but in head plot the distribution is wrong, if I change locations. Is there some coordinates of layout in head plot widget I can change?

    Thanks :-)

    Jussi
  • jussijaatinenjussijaatinen
    Ok. I found this: electrode_positions_default.txt.

    It looks like this:

    X,Y
    -0.125,-0.416
    0.125,-0.416
    -0.2,0.0
    0.2,0.0
    -0.3425,0.27
    0.3425,0.27
    -0.125,0.416
    0.125,0.416
    -0.3425,-0.27
    0.3425,-0.27
    -0.18,-0.15
    0.18,-0.15
    -0.416,0.0
    0.416,0.0
    -0.18,0.15
    0.18,0.15
    0.0,0.0

    Now, does OpenBCI_GUI read this file? 
    Could we have also coordinates for other nodes in MarkIV? Then it could be easy to create different electrode layouts.

    Jussi
  • jussijaatinenjussijaatinen
    What is the purpose of the last coordinate point (R in head plot)? Is it some kind of reference or what?

    J
  • wjcroftwjcroft Mount Shasta, CA
    Jussi, I merged your question into this previous thread on the same subject. Can you open an issue here,


    Explain your desire to edit the default headmap and that you want a howto, document, or guidance on how to do that. I think this addresses @compmonks question also.
  • celticharpcelticharp Athens, Greece
    edited February 2017
    I would also like that. I have created an issue on github. 
  • jeyemjeyem
    Hi,

    I did not find a threat or tutorial on that issue. I figured out that the electrode positions of the headplot are adjustable by drag and drop. However, I have to do this every time I restart the GUI. Is there a way to save a chosen configuration?


    Thanks,
    Johannes
  • wjcroftwjcroft Mount Shasta, CA
    @jeyem, hi.

    Merged your new thread into this existing one. Can you check the issues page?

    William

  • jeyemjeyem
    edited February 2018
    Hi @wjcroft,

    thanks for merging. The comment by @jussijaatinen actually effectively solves this issue. Just go to ~\OpenBCI_GUI\data than open the file electrode_positions_default.txt and change the settings according to your setup (You may wish to make a backup of the original file first). When starting the GUI, the head plot widget will always read out this file. It would be convenient, to know the coordinates of the other nodes of Ultracortex Headset, however by playing around one should get the right estimates oneself.

    Johannes
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