Source: https://docs.expo.dev/versions/v52.0.0/sdk/accelerometer

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Expo Accelerometer

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A library that provides access to the device's accelerometer sensor.

GitHub Changelog npm

Android

iOS (device only)

Web

Bundled version:

~14.0.2

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Accelerometer from expo-sensors provides access to the device accelerometer sensor(s) and associated listeners to respond to changes in acceleration in three-dimensional space, meaning any movement or vibration.

Installation

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Terminal

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- npx expo install expo-sensors

If you are installing this in an existing React Native app , make sure to install expo in your project.

Usage

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Basic Accelerometer usage

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Open in Snack

import { useState, useEffect } from 'react'; import { StyleSheet, Text, TouchableOpacity, View } from 'react-native'; import { Accelerometer } from 'expo-sensors'; export default function App() { const [{ x, y, z }, setData] = useState({ x: 0, y: 0, z: 0, }); const [subscription, setSubscription] = useState(null); const _slow = () => Accelerometer.setUpdateInterval(1000); const _fast = () => Accelerometer.setUpdateInterval(16); const _subscribe = () => { setSubscription(Accelerometer.addListener(setData)); }; const _unsubscribe = () => { subscription && subscription.remove(); setSubscription(null); }; useEffect(() => { _subscribe(); return () => _unsubscribe(); }, []); return ( <View style={styles.container}> <Text style={styles.text}>Accelerometer: (in gs where 1g = 9.81 m/s^2)</Text> <Text style={styles.text}>x: {x}</Text> <Text style={styles.text}>y: {y}</Text> <Text style={styles.text}>z: {z}</Text> <View style={styles.buttonContainer}> <TouchableOpacity onPress={subscription ? _unsubscribe : _subscribe} style={styles.button}> <Text>{subscription ? 'On' : 'Off'}</Text> </TouchableOpacity> <TouchableOpacity onPress={_slow} style={[styles.button, styles.middleButton]}> <Text>Slow</Text> </TouchableOpacity> <TouchableOpacity onPress={_fast} style={styles.button}> <Text>Fast</Text> </TouchableOpacity> </View> </View> ); } const styles = StyleSheet.create({ container: { flex: 1, justifyContent: 'center', paddingHorizontal: 20, }, text: { textAlign: 'center', }, buttonContainer: { flexDirection: 'row', alignItems: 'stretch', marginTop: 15, }, button: { flex: 1, justifyContent: 'center', alignItems: 'center', backgroundColor: '#eee', padding: 10, }, middleButton: { borderLeftWidth: 1, borderRightWidth: 1, borderColor: '#ccc', }, });

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API

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import { Accelerometer } from 'expo-sensors';

Classes

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Accelerometer

Android

iOS

Web

Type: Class extends [DeviceSensor](https://docs.expo.dev/versions/latest/sdk/sensors) <[AccelerometerMeasurement](https://docs.expo.dev/versions/v52.0.0/sdk/accelerometer#accelerometermeasurement) >

A base class for subscribable sensors. The events emitted by this class are measurements specified by the parameter type Measurement.

Accelerometer Methods

addListener(listener)

Android

iOS

Web

| Parameter | Type | Description | | --- | --- | --- | | listener | Listener<[AccelerometerMeasurement](https://docs.expo.dev/versions/v52.0.0/sdk/accelerometer#accelerometermeasurement) > | A callback that is invoked when an accelerometer update is available. When invoked, the listener is provided a single argument that is an AccelerometerMeasurement object. |

Subscribe for updates to the accelerometer.

Returns:

EventSubscription

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

getListenerCount()

Android

iOS

Web

Returns the registered listeners count.

Returns:

number

getPermissionsAsync()

Android

iOS

Web

Checks user's permissions for accessing sensor.

Returns:

[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) <PermissionResponse>

hasListeners()

Android

iOS

Web

Returns boolean which signifies if sensor has any listeners registered.

Returns:

boolean

isAvailableAsync()

Android

iOS

Web

You should always check the sensor availability before attempting to use it.

Returns whether the accelerometer is enabled on the device.

On mobile web, you must first invoke Accelerometer.requestPermissionsAsync() in a user interaction (i.e. touch event) before you can use this module. If the status is not equal to granted then you should inform the end user that they may have to open settings.

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:

[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) <boolean>

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

removeAllListeners()

Android

iOS

Web

Removes all registered listeners.

Returns:

void

removeSubscription(subscription)

Android

iOS

Web

| Parameter | Type | Description | | --- | --- | --- | | subscription | EventSubscription | A subscription to remove. |

Removes the given subscription.

Returns:

void

requestPermissionsAsync()

Android

iOS

Web

Asks the user to grant permissions for accessing sensor.

Returns:

[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise) <PermissionResponse>

setUpdateInterval(intervalMs)

Android

iOS

Web

| Parameter | Type | Description | | --- | --- | --- | | intervalMs | number | Desired interval in milliseconds between sensor updates.<br><br>> Starting from Android 12 (API level 31), the system has a 200ms limit for each sensor updates.<br>> <br>> If you need an update interval less than 200ms, you should:<br>> <br>> * add android.permission.HIGH_SAMPLING_RATE_SENSORS to app.json permissions field<br>> <br>> * or if you are using bare workflow, add <uses-permission android:name="android.permission.HIGH_SAMPLING_RATE_SENSORS"/> to AndroidManifest.xml. |

Set the sensor update interval.

Returns:

void

Interfaces

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PermissionResponse

Android

iOS

Web

An object obtained by permissions get and request functions.

| Property | Type | Description | | --- | --- | --- | | canAskAgain | boolean | Indicates if user can be asked again for specific permission. If not, one should be directed to the Settings app in order to enable/disable the permission. | | expires | [PermissionExpiration](https://docs.expo.dev/versions/v52.0.0/sdk/accelerometer#permissionexpiration) | Determines time when the permission expires. | | granted | boolean | A convenience boolean that indicates if the permission is granted. | | status | [PermissionStatus](https://docs.expo.dev/versions/v52.0.0/sdk/accelerometer#permissionstatus) | Determines the status of the permission. |

Types

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AccelerometerMeasurement

Android

iOS

Web

Each of these keys represents the acceleration along that particular axis in g-force (measured in gs).

A g is a unit of gravitational force equal to that exerted by the earth’s gravitational field (9.81 m/s^2).

| Property | Type | Description | | --- | --- | --- | | timestamp | number | Timestamp of the measurement in seconds. | | x | number | Value of gs device reported in X axis. | | y | number | Value of gs device reported in Y axis. | | z | number | Value of gs device reported in Z axis. |

PermissionExpiration

Android

iOS

Web

Literal Type: union

Permission expiration time. Currently, all permissions are granted permanently.

Acceptable values are: 'never' | number

Subscription

Android

iOS

Web

A subscription object that allows to conveniently remove an event listener from the emitter.

| Property | Type | Description | | --- | --- | --- | | remove | () => void | Removes an event listener for which the subscription has been created. After calling this function, the listener will no longer receive any events from the emitter. |

Enums

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PermissionStatus

Android

iOS

Web

DENIED

PermissionStatus.DENIED ＝ "denied"

User has denied the permission.

GRANTED

PermissionStatus.GRANTED ＝ "granted"

User has granted the permission.

UNDETERMINED

PermissionStatus.UNDETERMINED ＝ "undetermined"

User hasn't granted or denied the permission yet.