This doesn't seem to be true. I wrote to FitBit and this is their answer: "... unfortunately the Fitbit trackers can't notify you when you are falling asleep. T

This doesn't seem to be true. I wrote to FitBit and this is their answer: "... unfortunately the Fitbit trackers can't notify you when you are falling asleep. They have only silent alarms, which you can setup manually and reminders to move for every hour. The tracker vibrates on your wrist, reminding you to stand up and walk. For more information, please visit Silent Alarms, Reminders to Move."