Calibration setting in Cyton through OpenBCI

VedashreeVedashree India
edited August 2023 in Cyton

Hi,
I am new to using Cyton board. I want to check the board output with test signal mentioned in Calibration section of ADS1299 datasheet. Can anyone specify the steps to check the calibration for the board in OpenBCI ?. I just couldn't figure out how to calibrate the board and observe the resulting waveform in the Plot.

Thank you.

Comments

  • I wanted to check the test signal with different gain settings and observe the output. Hence the title.

  • wjcroftwjcroft Mount Shasta, CA

    It is not required or recommended to 'calibrate' the Cyton, as this has already been done in design / manufacturing steps. If you wanted you could carefully use a signal generator with a voltage divider network to get the output in the range desired.

    https://www.google.com/search?q=voltage+divider+calculator

    I'd suggest keeping output below 1 volt. You don't want to exceed the plus and minus power supply rails on the ADS1299.

  • Thank you wjcroft for the reply.
    I observed waveform changes in OpenBCI plot window when other person walks by the setup, even when no gesture was performed by the actual gesture performer. I wanted to know the reason for such behavior. I suspected all INxP channels and wanted to check through calibration. According to your reply the board has already been calibrated.
    So I suspect BIAS pin for presenting disturbance from surroundings. Is my assumption correct?
    Please suggest how to reduce such behavior.
    Thank you.

  • wjcroftwjcroft Mount Shasta, CA

    EMF Electromagnetic field interference is very common from equipment or proximity to: extension cords, power supplies, wall warts, conduits (walls, ceiling, floors), metallic tables, wifi / cellular equipment, roof or tower mounted cell antennas, etc etc.

    Experiment with positioning your equipment away from such sources. Bodies can act as bridges / conveyors of such fields.

    EEG is also very sensitive to motion artifact, regardless of it coming from the subject or someone brushing / passing by the subject.

  • So, ECGP, ECGN and RLD input pins sensitivity is the reason for such behavior!
    Thank you wjcroft for the clarification.

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