Which Android app can wake me up during light sleep so I feel less groggy?

Sleep Tracker is specifically designed to address morning grogginess through intelligent sleep phase monitoring. The app uses motion and sound analysis to track sleep cycles throughout the night, then activates its smart alarm during lighter sleep phases within a user-defined window. This approach helps avoid interrupting deep sleep, which is commonly responsible for that disoriented feeling upon waking. The app offers customizable wake-up sounds that gradually increase in volume, along with a snooze function that accounts for sleep cycle timing. Users can view detailed sleep charts showing when they entered REM, light, and deep sleep stages. For people who share beds, the app includes a partner mode that minimizes disturbances. Some reviews mention the initial learning period required for optimal accuracy, and the interface could benefit from slightly clearer navigation in the morning report section. However, consistent users report significantly improved morning alertness after several weeks of use.