the Fitbit Tracker contains a motion sensor like the ones found in the Nintendo Wii. The Tracker senses your motion in three dimensions and converts this into useful information about your daily activities. The Tracker measures the intensity and duration of your physical activities, calories burned, steps taken, distance traveled, how long it took you to fall asleep, the number of times you woke up throughout the night and how long you were actually asleep vs just lying in bed
