Last Updated on April 1, 2024 by pg@petergamma.org
Gold standard for sleep tracking is Polysomnography
https://en.wikipedia.org/wiki/Polysomnography
it requires 12 channels
and 22 wires.
Pictures taken from Wikipedia about polysomnography
https://en.wikipedia.org/wiki/Polysomnography
Peter Gamma from www.petergamma.org invites you to build such a device with OpenBCI 16 channels.