From Krisztián Hofstädter, PhD in brain-computer music interfacing and meditation
https://www.linkedin.com/in/tedor/?originalSubdomain=uk
we have a YouTube demo with OpenBCI, Greentek Gelfree S 03 and high alpha waves:
From these scientists using EEG caps and making animal tests with OpenBCI:

we do not know of a demo showing brain waves, and we could also not find a demo which is published with this setup.