Cyton, channels max out at 187000 uV; also "Skipped 18 bytes before start found"

WechnikWechnik Russia
edited December 2018 in Cyton
I have been using OpenBCI Cython board for data collection. Unfortunately i have noticed that pretty frequently the error occurres. Some channels stops working and give constant(± 187500.02235174) as an output. Is there any solution to this problem? The plugin i am using give me the following message: ”Warning: Skipped 18 bytes before start found”. For more information, i am attaching data that were collected with and without the error.

Comments

  • wjcroftwjcroft Mount Shasta, CA
    Wechnik, hi.

    The 187000 uV value is the maximum microvolts, (187 millivolts, .187 volts), when the channel goes, "off the scale" in plus or minus direction. This can be caused by a large DC offset. For example if a gold electrode is chipped, it can form a "galvanic circuit" that acts like a small battery. Can you try swapping your electrode leads around to eliminate the cause of a bad electrode or reference lead connection?

    The maximum value 187000 uV is obtained when using the default scale factor of x24. You can use the GUI to try other scale factors, which max out at higher values. But clearly you have issues with your electrodes or channels.

    re: skipped bytes, this is normal when synching up, but should not repeat during the session. If it is repeating often, then you might have a connectivity problem between the RFduino radios (Bluetooth). You could try changing the radio channel, in case there is nearby interference.

    Regards,

    William

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