Zeo Personal Sleep Coach

[karthik4096]

http://www.myzeo.com/

anyone tell me how it detects deep sleep.

[DJPhil]

I don't know for sure, but I'll guess.

The EEG probe picks up low voltage, low frequency oscillations which are amplified, converted to digital, and fed into a microcontroller. Standards have been agreed upon that define sleep stages by characteristic changes in these oscillations, and the microcontroller will compare what it's sensing against a reference to determine sleep stage.

From there it's standard microcontroller stuff (actually, the whole thing is pretty standard). The uC will handle datalogging, display, alarms, and other input as desired.

[MTron]

Pretty much hit it right on the mark! Thats exactly how it works

There are a few characteristic waveform shapes that one must look for that define deep sleep. These were defined experimentally by examining a number of people while in different sleep states to define a general baseline average.

Wikipedia has a great page if you want to know more

http://en.wikipedia.org/wiki/Electroencephalography