EEG system for a float tank
I am trying to build an EEG system that can be used inside a float tank. This is a bit of a problem, since we are talking about a giant salt bath. I don't think I need the whole head -- just frontal electrodes will do. I like the look of the Ultracortex Mark IV with active dry electrodes, but it looks like the CytonDaisy board is built to go in the back of the head on that helmet, which would be underwater. Big no.
The other option I see is to use a normal fabric electrode cap, like I see in the Gelfree Electrode Cap kit, and then put a swim cap over that to try to ensure dryness. The lower profile of the passive electrodes gives me more flexibility, and I can place the CytonDaisy board farther away from the water.
What do you think? Any recommendations for me? Thanks
Comments
Hi BTL,
The issue may be that whatever precautions you take to protect the electrodes and circuit board, the salt water will tend to seep under edges and short things out. There may be waterproof diver type underwater boxes for the battery and board. (Assuming gaskets / (called 'glands')) for the wires to emerge.
https://www.google.com/search?q=underwater+diver+box+for+electronics
https://www.google.com/search?q=underwater+gasket+gland
But doing the same thing for the scalp is going to be much harder. I don't believe a swim cap is going to be enough. All caps I'm aware of allow water to seep under the cap.
IDUN previously made special underwater electrodes. But those I think assumed non-salt water, I may be wrong. As you know salt water conducts much higher then non-salt.
https://openbci.com/community/brand-new-waterproof-dry-electrode-kit-from-idun-technologies/
Also the IDUN electrodes were designed for measuring millivolt level ECG and EMG signals. EEG is in microvolts, say from 1 to 80 uV. Unclear if EEG can be measured underwater. Also IDUN seems to have shifted over to other product lines. They might still have the Dryodes but not actively selling them.
https://iduntechnologies.com/
https://iduntechnologies.com/our-company/milestones
https://drive.google.com/file/d/1wOXuqx8djf53mynuzk-8Rp5iFHNrh8lj/view
Regards, William
Looks like some labs have found solutions. Unclear which of these are salt water.
https://www.google.com/search?q=measuring+eeg+under+water
https://mbraintrain.com/eeg-during-swimming/