Sleep tracking #

Sleep tracking allows you to objectively monitor and analyze the quality of your rest.

By tracking your sleep, the app enables you to:

• Visualize: View a detailed sleep graph for every night.
• Monitor: Track long-term trends with your Sleep Score and Statistics.
• Improve: Set personal goals to enhance your sleep hygiene.
• Wake Up Refreshed: Use Smart Wake Up to wake up during your lightest sleep phase.

For the science behind these features, see Sleep Tracking Theory.

How to Track Sleep#

To get the most accurate insights into your rest, the app utilizes one primary sensor and optionally a handful of additional sensors. Choose from several sensor options to monitor your sleep:

Accelerometer#

Every smartphone is equipped with an accelerometer. This sensor detects movement; the core principle is that as you shift during sleep, your movements vibrate the mattress, which the phone then records.

Positioning the Phone for Accelerometer Tracking#

For the accelerometer to work, the phone must be placed directly on the mattress.

The accuracy of measured data depends heavily on how well your bed is able to transmit your movement to the phone:

Sonar#

Sleep as Android technology turns your phone’s microphone and speaker into a sonar system. By emitting ultrasonic waves, the app detects your movement and respiration through frequency shifts. This allows for contactless tracking.

It works on many phones, but not all (some are unable to produce or capture frequencies above human hearing range).

Read more about sonar and how we invented it.

Positioning the Phone for Sonar Tracking#

Because ultrasonic waves lose energy over distance, precise placement is key:

• Surface: Place the phone on a steady, flat surface (like a bedside table).
• Height: The phone should be at the same level as your body or slightly higher (chest level).
• Direction: Point the bottom of the phone (where the microphone usually sits) directly toward your chest.
• Clearance: Ensure there are no large objects (lamps, water bottles) blocking the “line of sight” between the phone and your body.

Other Devices#

If you prefer not to keep your phone near your bed at all, you can integrate external devices like the Sleep Phaser or Wearables.

The Tracking Screen#

When tracking is active, the screen provides real-time data and quick actions.

Pull up menu#

Sliding up the Pull up menu menu will bring up further options:

Option	Description
Stop	End the current sleep tracking (no confirmation needed).
Night light	Turn on the phone’s flashlight or any connected Smartlight. It will use it at minimum brightness (and red if possible) to help you navigate the room.
Tags	Add tags or notes to the current sleep entry.
Lullabies	Start lullaby sounds.
Save battery	Switches sleep tracking into a low power mode. In this mode, tracking will consume minimum battery, but Noise Recording will be stopped and no activity will be tracked using sensors. Useful if you don’t have much battery but still want to track your sleep time.

Key Settings Explained#

Explore advanced automation, battery optimization, and specialized features in Settings → Sleep tracking.

Awake Detection#

Smart algorithms that recognize when you are actually awake vs. just moving in your sleep. Learn more in our Awake Detection guide.

Automatic Tracking#

Set the app to start and stop tracking based on your schedule or movement using Automatic Tracking.

Sensor#

Choose the sensor that will be used for motion tracking when you track using your phone (i.e., without wearables or Sleep Phaser).

Wearables#

Choose your wearable as the sleep tracking sensor. If a wearable is selected and paired, the app will not use the phone’s built-in sensors.

Pair Tracking#

Sync with a partner to filter out their movements from your data and obtain a cleaner sleep record.

Lullabies#

Play melodies, audiobooks, or white noise that automatically fades out once the app detects you have fallen asleep. Read more about Lullabies.

Lucid Dreaming#

Uses sound or light cues during REM sleep to help you realize you are dreaming without waking you up. See Lucid Dreaming.

Jet Lag Prevention#

Tools to help shift your circadian rhythm when traveling across time zones.

Screen Dimming#

Controls the display behavior during the night to save battery and reduce light disturbance:

• Disabled: System default timeout applies.
• Dim: Screen darkens but stays active.
• Dim with Clock: Shows a dim clock; system timeout applies.
• Always on Clock: Keeps a dim clock visible all night. (WARNING: High battery usage).

Do Not Disturb (DND)#

Automatically silences notifications when you start tracking to ensure an undisturbed night.

• Priority Mode: Allows emergency contacts to bypass DND while you sleep.

Stand-by#

Automatically stops tracking if your battery drops below a specific percentage to ensure your alarm still has enough power to ring in the morning.

Battery Optimized#

Enables “sensor batching,” which allows the phone’s CPU to sleep while the sensor collects data.

• Unavailable when using Sonar or Noise Recording.
• Due to Android’s “Doze mode,” we schedule a user-visible alarm every minute to keep batching active. This alarm will never ring but will be visible on your lockscreen.
• May affect awake detection accuracy on some phone models.

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