electrode shapes, sizes, saline usage

ynivekcynivekc Sydney, Australia
edited January 16 in Electrodes

Hi,
I've been looking into designing an EEG Headset using the OpenBCI Ganglion board. However, the concept designs that I've been working with would be greatly improved if the dry AgCl electrodes were different shapes and sizes, or if they used a different medium.
I was wondering if other anybody else have considered or tried making your own dry comb electrodes, and is it feasible for me to use home-made electrodes for a trial? What are the main considerations when I should go about producing and designing the electrodes?
We've also been considering using saline electrodes as well. I've read that the ganglion device is compatible with the OpenBCI saline cap, is it possible for us to use custom saline electrodes?
Thanks,
Kevin

Comments

  • wjcroftwjcroft Mount Shasta, CA

    The electrodes at FRI are inexpensive. The dry electrodes are a plastic base, first plated with a thin layer of silver, which is then chlorided. They also sell some gold electrodes. Silver chloride always gives the most stable EEG, but does wear over time. I don't believe do-it-yourself molding, casting, plating, chloriding would be very enjoyable. These companies make these in large quantities.

    https://fri-fl-shop.com/

    Saline based systems have also been made with cup electrodes, contacting a saline soaked pad. Such as Pete Van Deusen's caps.

    https://brain-trainer.com/shop/products/caps-sensors-supplies/

    All EEG systems are compatible with saline headsets. Generally your EEG signals will be much higher quality with saline systems. The dry combs and cones and disks require considerable pressure to obtain even passably low impedance. The saline gives you good impedance in all cases.

    Here is a saline system I put together some time ago, and used with many clients for neurofeedback.

    https://sites.google.com/site/biofeedbackpages/velcro-saline-sensors

    William

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