measuring impedance of single vs several electrodes at once [resolved]

ht_steve1976ht_steve1976 Japan
edited April 2021 in OpenBCI_GUI

When the impedance of one electrode is measured by OpenBCI_GUI, the impedance is relatively low. However, when several electrodes are measured at the same time, the impedance becomes higher. Which impedance is correct?
I'm using OpenBCI_GUI v4.1.7. Sorry if this problem was solved.



Comments

  • retiututretiutut Louisiana, USA
    edited April 2021

    Thanks for reaching out,

    The ADS1299 chip on the Cyton allows us to accurately check the impedance on one electrode at a time.

    Checking impedance involves injecting a small amount of current to a given Pin. Injecting current into more than one channel will distort all measurements from most channels.

    In the future, we may need to modify the GUI to reflect this.

    Also, we are now using GUI v5.0.4. I think the version you are using is over a year old. I see you are using LSL output with TimeSeries data type, which was broken in the version you have here. You definitely need to update to 5.0.4 for this to work correctly.

    https://www.openbci.com/downloads

    Take Care,
    RW

  • ht_steve1976ht_steve1976 Japan

    Thank you very much for your comment.
    I understood we should check the impedance on one electrode at a time, and the reason why.

    The information of LSL is surprising... I read the some release notes, but I didn't get it. What part of it was broken?
    Anyway, thank you so much for telling me.

  • retiututretiutut Louisiana, USA
    edited April 2021

    I think part of the Networking widget was not sending out all of the samples when using TimeSeries and LSL. It was a very specific fix.

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