It then waits till you fall asleep then starts the timer, waiting for you to get roughly 26.5 minutes of shuteye, before rousing you during alightsleep cycle.
Instead of making a loud noise at a predetermined time, the Smart Alarm gently vibrates when you're in alightsleep, somewhere around the time you'd like to wake up (up to 30 minutes before you've actually set it).
You see, researchers now know that blue-tinted light suppresses production of melatonin a hormone that makes it easier for us to go to sleep at night while red light does not (I wrote about the topic in a bit more detail here).