Expo

Documentation

DeviceMotion

DeviceMotion from expo-sensors provides access to the device motion and orientation sensors. All data is presented in terms of three axes that run through a device. According to portrait orientation: X runs from left to right, Y from bottom to top and Z perpendicularly through the screen from back to front.

Platform Compatibility

Android DeviceAndroid EmulatoriOS DeviceiOS SimulatorWeb
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Installation

For managed apps, you'll need to run expo install expo-sensors. To use it in a bare React Native app, follow its installation instructions.

API

import { DeviceMotion } from 'expo-sensors';

Methods

DeviceMotion.isAvailableAsync()

You should always check the sensor availability before attempting to use it.
Returns whether the DeviceMotion API is enabled on the device.
On web this starts a timer and waits to see if an event is fired. This should predict if the iOS device has the device orientation API disabled in Settings > Safari > Motion & Orientation Access. Some devices will also not fire if the site isn't hosted with HTTPS as DeviceMotion is now considered a secure API. There is no formal API for detecting the status of DeviceMotion so this API can sometimes be unreliable on web.

Returns

  • A promise that resolves to a boolean denoting the availability of the sensor.

DeviceMotion.addListener(listener)

Subscribe for updates to DeviceMotion.

Arguments

  • listener (function) -- A callback that is invoked when a DeviceMotion update is available. When invoked, the listener is provided a single argument that is an object containing following fields:
    • acceleration (object) -- Device acceleration on the three axis as an object with x, y, z keys. Expressed in m/s2.
    • accelerationIncludingGravity (object) -- Device acceleration with the effect of gravity on the three axis as an object with x, y, z keys. Expressed in m/s2.
    • rotation (object) -- Device's orientation in space as an object with alpha, beta, gamma keys where alpha is for rotation around Z axis, beta for X axis rotation and gamma for Y axis rotation.
    • rotationRate (object) -- Rotation rates of the device around each of its axes as an object with alpha, beta, gamma keys where alpha is around Z axis, beta for X axis and gamma for Y axis.
    • orientation (number) -- Device orientation based on screen rotation. Value is on of 0 (portrait), 90 (right landscape), 180 (upside down), -90 (left landscape).

Returns

  • A subscription that you can call remove() on when you would like to unsubscribe the listener.

DeviceMotion.removeAllListeners()

Remove all listeners.

DeviceMotion.setUpdateInterval(intervalMs)

Subscribe for updates to DeviceMotion.

Arguments

  • intervalMs (number) Desired interval in milliseconds between DeviceMotion updates.