[gkbrk]

The Android app "Sleep as Android" [1][2] is awesome as well. Uses ultrasound to detect your movement/breathing and wakes you up at the correct part of the sleep cycle, even if your calculation goes wrong due to falling asleep later.

[1]: https://sleep.urbandroid.org/

[2]: https://play.google.com/store/apps/details?id=com.urbandroid...