Upgrade to active electrode setup from a passive one

ssaxenassaxena IIT Kanpur
edited October 2024 in Electrodes

I had purchased https://shop.openbci.com/products/all-in-one-gelfree-electrode-cap-bundle. It comes with a Cyton Daisy Board, EEG Cap, and necessary wires, etc.  It is a setup for Passive electrodes. How do I convert it to an active electrode setup of 16 channels? What all will I need?
Also, What other gel-based electrodes are compatible with this setup?
Are gel based electrodes better than active dry electrodes?

Comments

  • wjcroftwjcroft Mount Shasta, CA

    @ssaxena said:
    ...  It is a setup for Passive electrodes. How do I convert it to an active electrode setup of 16 channels? What all will I need?

    In general terms, 'wet' electrodes systems, such as gel based or the 'saline' gel-free that you have, give excellent results when used passively. The reason 'active' amplification is popular with dry electrodes, is that the signal amplitude from passive dry is slightly weaker than passive wet. So putting a small active amplifier behind each dry electrode improves signal quality. This is especially the case with dry electrodes made of conductive rubber, such as used in the Thinkpulse actives. Some dry electrodes using silver chloride combs, have stronger signal quality than rubber, thus work reasonably used passively.

    https://shop.openbci.com/products/thinkpulse-active-electrode-kit

    Your existing cap should provide excellent signal quality as it is. It cannot be 'upgraded' to actives. The Thinkpulse actives only work with the Ultracortex headset.

    Also, What other gel-based electrodes are compatible with this setup?

    You do not need gel electrodes or gel with the cap you already have.

    Are gel based electrodes better than active dry electrodes?

    Already explained this. If you have further questions you can email Customer Support (contact at openbci.com).

    William

  • ssaxenassaxena IIT Kanpur
    edited October 2024

    I have had the setup for over 2 years and the signal quality has recently degraded a lot. Are these corroded? Do I need to replace? Where will I find new ones?

    What could be other possible reasons for high resistance/ degraded signal quality & high rate of packet loss?

  • wjcroftwjcroft Mount Shasta, CA
    edited October 2024

    Please send an email to Customer Support (contact at openbci.com) and ask about the electrode wear inside the holders. The normal 'grey' silver chloride coating seems to be worn away, exposing the plastic layer below. It should be possible to order replacements. The manufacturer is Greentek in China. Send OpenBCI Customer Service a link to your Forum page.

    https://openbci.com/forum/index.php?p=/discussion/3928/upgrade-to-active-electrode-setup-from-a-passive-one

    https://www.greenteksensor.com/ [manufacturer, who may stock replacement parts]

    I also see there are email contact links on the page above, possibly contact them as well.

    'Packet loss' is a separate issue than high impedance. Try relocating to other lab rooms that have less electrical equipment nearby. Such as extension cords, power supplies, LED lighting, wireless gear, cell towers, etc.

    Regards,

  • ssaxenassaxena IIT Kanpur

    Thanks William, I have sent an email to customer care along with the link to this forum.
    Regards,
    Shatroopa

  • ssaxenassaxena IIT Kanpur

    Hi, I have not received any response over email neither from openbci nor greentek. Please suggest a replacement product. Thanks.

  • wjcroftwjcroft Mount Shasta, CA

    Hi @ssaxena, I've mentioned this Forum thread to the customer support staff. I hope they will have some suggestions. @Shirley .

    William

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