Expo

Documentation

Accelerometer

Access the device accelerometer sensor(s) to respond to changes in acceleration in 3d space.

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.

import { Accelerometer } from 'expo-sensors';

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

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

Subscribe for updates to the accelerometer.

  • listener (function) -- A callback that is invoked when an accelerometer update is available. When invoked, the listener is provided a single argument that is an object containing keys x, y, z.

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

Remove all listeners.

Subscribe for updates to the accelerometer.

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

import React from 'react';
import { StyleSheet, Text, TouchableOpacity, View } from 'react-native';
import { Accelerometer } from 'expo-sensors';

export default class AccelerometerSensor extends React.Component {
  state = {
    accelerometerData: {},
  };

  componentDidMount() {
    this._toggle();
  }

  componentWillUnmount() {
    this._unsubscribe();
  }

  _toggle = () => {
    if (this._subscription) {
      this._unsubscribe();
    } else {
      this._subscribe();
    }
  };

  _slow = () => {
    Accelerometer.setUpdateInterval(1000);
  };

  _fast = () => {
    Accelerometer.setUpdateInterval(16);
  };

  _subscribe = () => {
    this._subscription = Accelerometer.addListener(accelerometerData => {
      this.setState({ accelerometerData });
    });
  };

  _unsubscribe = () => {
    this._subscription && this._subscription.remove();
    this._subscription = null;
  };

  render() {
    let { x, y, z } = this.state.accelerometerData;
    return (
      <View style={styles.sensor}>
        <Text>Accelerometer:</Text>
        <Text>
          x: {round(x)} y: {round(y)} z: {round(z)}
        </Text>
        <View style={styles.buttonContainer}>
          <TouchableOpacity onPress={this._toggle} style={styles.button}>
            <Text>Toggle</Text>
          </TouchableOpacity>
          <TouchableOpacity onPress={this._slow} style={[styles.button, styles.middleButton]}>
            <Text>Slow</Text>
          </TouchableOpacity>
          <TouchableOpacity onPress={this._fast} style={styles.button}>
            <Text>Fast</Text>
          </TouchableOpacity>
        </View>
      </View>
    );
  }
}

function round(n) {
  if (!n) {
    return 0;
  }

  return Math.floor(n * 100) / 100;
}

const styles = StyleSheet.create({
  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',
  },
  sensor: {
    marginTop: 45,
    paddingHorizontal: 10,
  },
});