The headband has 3 electrodes on the forehead like NeuroOn and used an Fp1-Fp2 bipolar recording montage (two standard left and right frontopolar sites on the forehead). EEG recorded here is particularly prone to artifacts from eye movements and muscle activity and is thus a mixture of all these signals. Analytic techniques such as independent component analysis (ICA) try to separate the sources. The Zeo group used some sort of training algorithm that used "a combination of time and frequency dependent features derived from the signal to create a best estimate of sleep stage." Interestingly, they had to filter out the very low frequencies (below 2 Hz) that comprise much of the delta wave activity seen during slow wave sleep. This was because of contamination by excessive noise in the low frequency range.I have no idea of how any of Zeo technology relates to that used by NeuroOn, but the published paper presented some of the challenges involved in developing such a system.: While I'm at it, I should mention another neurocrap Kickstarter project -- Aurora: The Dream-Enhancing Headband , which was brought to my attention by Micah Allen . Save your money! If you want to support a worthwhile project, try OpenBCI: An Open Source Brain-Computer Interface For Makers , recommended as legit by Neurobonkers : New post from a sleep researcher: Nonsense neurogadgets: sleep edition , at Taking a cat apart