I read about bio-alarm clock few years back in high school, it’s made by bunch of MIT students using expensive electroencephalogram detectors. I never expected this sleep phase could be also detected using iPhone accelerometer.

the Sleep Cycle alarm clock is able to use the accelerometer in your iPhone to monitor your movement and determine which sleep phase you are in.

Pity I don’t have an iPhone nor any phone with accelerometer, or I will definitely buy this software and try it out :(

via