The free version of this app includes many features such as sleep tracking, smart alarms, goal setting, light and sound monitoring, bedtime reminders, sleep scores, and a seven-day sleep history. To use the sonar technology, you must leave your phone plugged in, above mattress level, and with the base of the phone pointed toward you (which may not be possible depending on your bedroom setup). The app formulates a sleep score to attach an objective number to your sleep quality to help with setting goals for better sleep. The app sends sonar waves from your phone to measure your breathing and any sounds, which allow it to track light, deep, and REM sleep and identify when you wake up during the night. As the most advanced sleep tracker on this list, SleepScore uses sonar technology to measure sleep habits from your nightstand.
