[191101]

This is quite nice but I feel a bit too simple. Sleep cycles vary widely from 70-120 minutes per person. I think an advanced mode where a person can input their own record of sleep duration would be nice. Or even getting a couple of sliders to play with varying REM, NREM cycles would be nice.

[natdempk]

I never knew this. How can someone determine how long their sleep cycle is? I’d love to figure out how long mine is.

[crooked-v]

A good sleep tracking device with an accelerometer can generally record light sleep vs heavy sleep periods. See worn devices like Fitbit Versa 2 or (with the new watchOS 7) Apple Watch 3 and later, or devices that sit on the mattress itself like Withings Sleep.

[joshternyak]

This is a great idea! I'll plan on adding this soon, if the tool gets more feedback and usage :)

[rckoepke]

Or hook into some wrist heart rate monitors / accelerometers (Garmin, Apple, etc) and correlate heart rate and movement with REM cycles. Wouldn't be surprised if this was already done too but no reason not to try it for a hobby endeavor. Gotta be tons of public research on the correlational methods available on Google Scholar.