How does the "SmartAlarm" function on my Philips SmartSleep Deep Sleep Headband work?

The SmartAlarm helps waking you up during your light sleep stage to reduce "sleep inertia", that is the time you spend feeling groggy in the morning. To set a SmartAlarm, go to the 'My Device' tab, click on Alarm, and enable SmartAlarm function. You will be asked to set the time you want to wake up and the wake-up window (up to 30 minutes before your desired wake up time). The headband detects what sleep stage you are at and gently wake you up when you are at light sleep within the pre-determined wake-up window, so you can wake up more naturally. If your headband slips off your head completely, you might not hear the alarm.