Lost samples warnings when Cyton is on my head.

SkalbeSkalbe Latvia
edited March 20 in Cyton

When my Cyton is just standing on my table, no samples (packets) are being lost.
When I connect the earlobe clips, still no samples are being lost.
When I lift it up, still fine. But when I put it on my head, it starts spamming warning about lost samples.
There are brief moments when it is all fine and during these moments the signal is also recognizably normal, but when the samples are being lost, the timeseries graph is showing noisy garble by my understanding.
I changed my headset for the openbci headstrap setup to reduce the threshold of what might be wrong, but the behavior stays the same.
Can anyone relate or guess what could be happening?
Thank you.


  • wjcroftwjcroft Mount Shasta, CA

    Skalbe, hi.

    Richard and others have found, that putting the dongle on a several foot long usb extension can help get it away from sources of RF attenuation or interference. You can then 'drape' the dongle in the air, for example off the edge of one of your monitor screens. The open air positioning of the dongle then helps in better signal reception.


  • wjcroftwjcroft Mount Shasta, CA

    It's also possible that there is a large amount of other wireless transmission in your area: wifi, bluetooth, cell towers, etc. Or EMF interference from lights, power supplies, wall / ceiling conduits, extension cords, etc. Trying other locations may improve operation.

    In all cases, as the dongle gets closer to the Cyton, the signal strength should increase. In the worst case, a longer usb extension cable can allow dongle to be even closer to mainboard.

  • retiututretiutut Louisiana, USA
    edited March 21

    We also recommend using the Packet Loss widget in the GUI for more advanced troubleshooting with EMF issues related to certain environments.

    Critically low battery is the most common cause of dropped packets.

    Hope this helps,

  • SkalbeSkalbe Latvia

    Hi guys!
    I was not aware of that widget. Thank you!
    So I charged up my battery and made sure to reconnect it to the charger a few times as it would show the red led after the first few reconnects after it had shown green. Could this mean that my battery is just old?
    I proceeded to test with just a pure board, no wires. If the board sits about 20cm off the dongle, everything is ok.
    If I take the board about a meter away from the dongle in my hand, packet loss would get up to 98% instantly.
    But then what I think was interesting, is I just put the board on my head and tested the first distance (around 20cm) and noticed that there was packet loss appearing of a ~20%, so I moved my head around changing the vector that is going from the dongle to cyton so that it would go through my head and not through my head. And this would again show packet loss up to 98% in the case where the vector passes through my head. Like if I hold it right above the dongle with my chin touching it and cyton on my head.
    So in effect my head is interfering and creating packet loss. Could this just be related to an old battery also? Because I know it worked just fine a few weeks ago and before that. My environment has not changed since then. I've had the battery for about two years. and recharged only a few times. All of my gear is from adafruit.

  • wjcroftwjcroft Mount Shasta, CA

    Regarding battery testing, it sounds like you are using a lithium cell from Adafruit. To eliminate the battery as a cause, I'd suggest using the OpenBCI supplied AA battery holder with fresh AA cells. This supplies 6 volts.

    Also remember that previous comments mentioned using a usb extension cable, to separate the dongle from direct contact with the laptop or possibly metal table / furniture the laptop is sitting on.


  • SkalbeSkalbe Latvia
    edited March 23

    Hi William!
    The dongle is just plugged into the usb drive. It is not touching anything else, while the Cyton board is in contact with just my hands or a wooden table.
    Will try the battery change.

  • wjcroftwjcroft Mount Shasta, CA

    The dongle is just plugged into the usb drive

    Can you clarify? You mean the usb 'port' on the side of your laptop? Using a usb extension cable will get the dongle away from metal surfaces such as metal tables, metal cabinets / enclosures, etc. Metal surfaces act like 'grounding' conductors to siphon away and weaken radio frequency transmissions from the dongle.

  • SkalbeSkalbe Latvia

    Ahh sorry I get it now, the purpose of the wire would also be to distance the dongle from ambient conductors and fields. Its just like this now, but it did work in this setup for a very long time and did not drop samples. I still have to resolder the trippleA battery pack.

  • wjcroftwjcroft Mount Shasta, CA

    It's also possible the 'ambient' EMF / RF fields in your location have changed over time. Such as with the installation of other wireless / cell equipment in your building or nearby. Thus positioning the dongle in as optimal location as possible, can help.

  • SkalbeSkalbe Latvia

    Hi William,
    While testing with a usb extension I found out that the interference would appear if the dongle is nearby the same usb port as where my Oculus VR is connected AND if the Cyton is on my head. I moved it around on the extended wire and if I moved it right nearby the Oculus port, it would start rapidly losing packets. Furthermore I could not reproduce the packet loss with the Oculus turned off. Makes sense I suppose since the Oculus is quite performance heavy and a lot of data travels through that port. This is all with the same lithium battery.
    Cyton can easiliy be a meter away from the dongle in this setup and things like my body being between them or Oculus right on top of it, do not cause any interference.
    Perhaps this comes in handy for someone along the line.
    tl;dr: don't keep the dongle in a port near other active ports or use an extension.

  • retiututretiutut Louisiana, USA

    @Skalbe Great investigating and detective work! I'm happy to hear you were able to debug your environment to find something that works for your situation.

    Perhaps this comes in handy for someone along the line.

    Yes. This will help others. Thank You!


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