Guides
Plan-enterprise-icon
Expo Application Services
API Reference

Accelerometer

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.

Platform Compatibility

Android DeviceAndroid EmulatoriOS DeviceiOS SimulatorWeb
Status-success-iconStatus-success-iconStatus-success-iconStatus-failed-iconStatus-success-icon

Installation

Terminal
→ npx expo install expo-sensors

If you're installing this in a bare React Native app, you should also follow these additional installation instructions.

Usage

Basic Accelerometer usage
import React, { 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>
  );
}

%%placeholder-start%%const styles = StyleSheet.create({ ... }); %%placeholder-end%%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',
  },
});

API

import { Accelerometer } from 'expo-sensors';

Classes

Accelerometer

Type: Class extends DeviceSensor<AccelerometerMeasurement>

Accelerometer Methods

getListenerCount()

Returns the registered listeners count.

  • Undo-iconnumber

getPermissionsAsync()

Checks user's permissions for accessing sensor.

hasListeners()

Returns boolean which signifies if sensor has any listeners registered.

  • Undo-iconboolean

removeAllListeners()

Removes all registered listeners.

  • Undo-iconvoid

removeSubscription(subscription)

NameTypeDescription
subscriptionSubscription

A subscription to remove.

Removes the given subscription.

  • Undo-iconvoid

requestPermissionsAsync()

Asks the user to grant permissions for accessing sensor.

setUpdateInterval(intervalMs)

NameTypeDescription
intervalMsnumber

Desired interval in milliseconds between sensor updates.

Info-icon

Starting from Android 12 (API level 31), the system has a 200ms limit for each sensor updates.

If you need an update interval less than 200ms, you should:

  • add android.permission.HIGH_SAMPLING_RATE_SENSORS to app.json permissions field
  • 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.

  • Undo-iconvoid

Interfaces

PermissionResponse

An object obtained by permissions get and request functions.

NameTypeDescription
canAskAgainbooleanIndicates 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.
expiresPermissionExpirationDetermines time when the permission expires.
grantedbooleanA convenience boolean that indicates if the permission is granted.
statusPermissionStatusDetermines the status of the permission.

Types

AccelerometerMeasurement

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).

NameTypeDescription
xnumberValue of gs device reported in X axis.
ynumberValue of gs device reported in Y axis.
znumberValue of gs device reported in Z axis.

PermissionExpiration

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

Acceptable values are: 'never', number.

Subscription

NameTypeDescription
remove() => voidA method to unsubscribe the listener.

Enums

PermissionStatus

PermissionStatus.DENIED = "denied"

User has denied the permission.

PermissionStatus.GRANTED = "granted"

User has granted the permission.

PermissionStatus.UNDETERMINED = "undetermined"

User hasn't granted or denied the permission yet.

  • Message-iconAsk a question on the forums about Accelerometer
  • Github-iconView open bug reports for Accelerometer
  • Code-iconView source code for Accelerometer
  • Build-iconView package in npm Registry
  • Edit-iconEdit this page

Was this doc helpful?