Last Updated on January 7, 2024 by pg@petergamma.org
Krisztián Hofstädter OpenBCI setup with the Greentek Gelfree S3 cap as shown here:
This would be very interesting for meditators like us to study their brainwaves. But is this EEG cap reliable? What lets us doubt is that Krisztián Hofstädter shows in the following demo only 2 EEG channels:
These are tracked with the EEG cap, altough OpenBCI would allow up to 16 channels. We have here a second demo of the Greentek Gelfree S3 cap which shows an example with 24 channels:
But the example shows only the function of the cap during a view seconds. Then we have two papers from authors from Slovenia and Serbia which where performed with children which use the Greentek Gelfree S3 cap and published in PLOS ONE and sensors Basel:
We did not study yet these papers in detail and we do not criticise those for the moment. But the Greentek Gelfree S3 cap is on the market now for at least 4 years. It costs between 600 and 1000 USD, it is comfortable to wear, has a good look and offers a cap design which no one else has brought on the market before. Why can we not find a validation paper from Greentek which validates it for scientific research?
Furthermore the question arrises, why do companies like iWorx, g.tec medical, BIOPAC and Adinstruments not offer this cap in their shops? Did they test it and was it not reliable enough? Or did they not find any papers which use it and can convince those.
And why do other scientists or even student projects not buy this cap directly from Greentek Sensors in China, use it an publish their work? Such papers and projects can easily be found with Google picture search for Greentek Gelfree S3. Here the result:
But we can find there mainly pictures of the Greentek Gelfree S3 from exibitions and the projects we already mentioned but no other projects.