All channels with the same signal

Hello!
I have a problem. When I launch the Ultracortex helmet with Cyton and Daisy, all channels begin to show the same large noisy signal, at which the Railed is about 60-80%. The helmet worked fine before. All I did with it was take out the battery to charge it. I tried replacing the battery and charger, but it didn't help. What should I do, I'm afraid the board is dead?

Thank you!

Comments

  • wjcroftwjcroft Mount Shasta, CA

    Check your ear clips. The 'Reference' (SRB2) ear clip is shared in common with all 16 channels. So noise like this means you have a reference problem. If you have a DVM meter, check that electrode and connector and wire in the ear clip is working well with good conductivity. Compare the Ground/Bias ear clip with the reference ear clip. May see a difference.

  • SpaceDonutSpaceDonut Austria
    edited March 14

    I checked the connection on both ear clips with a multimeter. On the SRB clip the value is close to zero when checking the contact, and on the BIAS ear clip it is slightly higher. You can see the photo in the archive on my Google drive. I also attached a photo of the connection to the board. The difference is small and does not show a complete zero, as you can see in photos is 001 and 002. What else should I check?
    https://drive.google.com/file/d/1lchNNfQRWLMHdJX381QWbU5Dj3Lvm9kj/view?usp=sharing

  • wjcroftwjcroft Mount Shasta, CA

    Certainly try swapping the two ear clips as well.

    Another cause that could result in 1000's of microvolts of noise, is environmental EMF electromagnetic field interference. Have you tried tests in other rooms / buildings? EMF can be emitted by extension cords, power supplies, LED or CFL lamps, wireless equipment, conduits in (walls, floors, ceilings), etc. Does the strength of the noise change as you move around in the room?

  • Swapping didn't help. Regarding ambient interference - in general the device already worked fine in this place, so I don’t think that’s the problem, i turned off the lighting, no changes. Another room also doesnt change much. One time when i swapped clips now the noise level jumped from 90% to 50% if I pressed on the clips. Basically it remains at 50-60 percent.

  • wjcroftwjcroft Mount Shasta, CA

    If the noise level reduced when pressing on the clips, it could mean that the silver chloride plating on the electrodes is worn, degraded. How long have you used this headset?

    I suggest you email to customer service (contact at openbci.com) and ask if they have any other suggestions.

    Another reason I mentioned EMF noise, is that your time series looks somewhat periodic / repeating in patterns. Certain equipment will generate repeating EMF patterns.

  • I already wrote to the service over the weekend, but they still haven’t answered me, so I wrote here. I've been using the headset for two months about once a week. It is very strange that one evening I had good EEG readings, and that same evening they changed to this noise, which has not gone away since then.

    May be i will try to buy new earclips. Since i live in Europe it will take a month again, i think, to become them. Or it is doesnt matter from which manufacturer ill buy?

  • wjcroftwjcroft Mount Shasta, CA

    If you have only been using it two months, then it should not be an issue with ear clip wear.

    Try re-emailing the support contact.

    If for example there is a new cell tower or 5G small cell unit installed in your area (those are mounted outside on utility poles or building roofs), that that could be a noise source. In that case moving just one room away will still pickup this EMF. Have you tried other computers, other power suppies? Try a test in another building or outside battery powered.

  • I will try it all, thank you, and let you know if it helps!

  • Today I tried moistening my earlobes and pressing on the ear clips. This two actions returned the Railed to its normal values, on channel 10 I can even see myself blinking hard, but the noise is still quite loud so it's impossible to see anything else on another channels.

  • wjcroftwjcroft Mount Shasta, CA

    @wjcroft said:
    ...
    Try re-emailing the support contact.

    If for example there is a new cell tower or 5G small cell unit installed in your area (those are mounted outside on utility poles or building roofs), that that could be a noise source. In that case moving just one room away will still pickup this EMF. Have you tried other computers, other power suppies? Try a test in another building or outside battery powered.

    I'm running out of suggestions. Please email customer service.

  • SpaceDonutSpaceDonut Austria
    edited March 25

    Hi,
    Just a small update if someone gets some ideas.
    The support team also thought about ear clips. I replaced them with new ones, but it didn't help. I also noticed that about 70% of packets are lost after i became an warning message in GUI. Could the Dongle be causing the problem?
    P.S. i was using BrainFlow library when its started, may is some programm issue?

    Best regards

  • wjcroftwjcroft Mount Shasta, CA

    I've mentioned several times, that EMF electromagnetic interference from other nearby (or across the street) devices can both distort the EEG channels, AND it can cause the radio packets to not arrive properly at the laptop. Have you tried a test at a completely different location, and/or using another computer?

    Because you are getting exactly the same moderately periodic (spikes above at -3 and -1) signal on ALL channels, and you have eliminated issues with possible bad reference -- this noise is almost certainly coming from external EMF sources.

  • SpaceDonutSpaceDonut Austria
    edited March 25

    I tried 3 locations, in two of them i already used the device in the past and it was working fine. So i really don't think this is the issue

  • wjcroftwjcroft Mount Shasta, CA

    EMF meters:

    https://www.amazon.com/s?k=emf+meter

    'Some' phones are capable of EMF measurement, but only if they have a built-in 'magnetometer' (compass) chip. These are present in mid to high range phones.

    https://www.google.com/search?q=phone+apps+to+measure+emf

    I hope you are still in communications with customer support. I have run out of suggestions. A 'dongle failure' would not cause symptoms like you are showing.

    One other thing you could try is unplugging the Daisy add-on board, in case something weird has happened on that board. But I am not aware of any failure modes of Daisy that would cause the same exact noise on every channel (both Daisy and main board.)

    It IS possible to change the radio channel used by the Cyton and dongle. But the channel range is very narrow in the Bluetooth / wifi portion of the radio spectrum. Almost all other Bluetooth devices use 'channel hopping' / spread spectrum. So they basically use ALL channels. Cyton just uses one at a time.

    https://docs.openbci.com/GettingStarted/Boards/CytonGS/#5-optional-settings

    Channel selection is done with the drop down documentation at section 5.

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