Device Motion

This plugin provides access to the device's accelerometer. The accelerometer is a motion sensor that detects the change (delta) in movement relative to the current device orientation, in three dimensions along the x, y, and z axis.

Access is via a global navigator.accelerometer object.

Although the object is attached to the global scoped navigator, it is not available until after the deviceready event.

document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady() {
    console.log(navigator.accelerometer);
}

Report issues with this plugin on the Apache Cordova issue tracker

Installation

cordova plugin add cordova-plugin-device-motion

Supported Platforms

• Amazon Fire OS
• Android
• BlackBerry 10
• Browser
• Firefox OS
• iOS
• Tizen
• Windows Phone 8
• Windows

Methods

• navigator.accelerometer.getCurrentAcceleration
• navigator.accelerometer.watchAcceleration
• navigator.accelerometer.clearWatch

Objects

• Acceleration

navigator.accelerometer.getCurrentAcceleration

Get the current acceleration along the x, y, and z axes.

These acceleration values are returned to the accelerometerSuccess callback function.

navigator.accelerometer.getCurrentAcceleration(accelerometerSuccess, accelerometerError);

Example

function onSuccess(acceleration) {
    alert('Acceleration X: ' + acceleration.x + '\n' +
          'Acceleration Y: ' + acceleration.y + '\n' +
          'Acceleration Z: ' + acceleration.z + '\n' +
          'Timestamp: '      + acceleration.timestamp + '\n');
}

function onError() {
    alert('onError!');
}

navigator.accelerometer.getCurrentAcceleration(onSuccess, onError);

Browser Quirks

Values for X, Y, Z motion are all randomly generated in order to simulate the accelerometer.

Android Quirks

The accelerometer is called with the SENSOR_DELAY_UI flag, which limits the maximum readout frequency to something between 20 and 60 Hz, depending on the device. Values for period corresponding to higher frequencies will result in duplicate samples. More details can be found in the Android API Guide.

iOS Quirks

• iOS doesn't recognize the concept of getting the current acceleration at any given point.

• You must watch the acceleration and capture the data at given time intervals.

• Thus, the getCurrentAcceleration function yields the last value reported from a watchAccelerometer call.

navigator.accelerometer.watchAcceleration

Retrieves the device's current Acceleration at a regular interval, executing the accelerometerSuccess callback function each time. Specify the interval in milliseconds via the acceleratorOptions object's frequency parameter.

The returned watch ID references the accelerometer's watch interval, and can be used with navigator.accelerometer.clearWatch to stop watching the accelerometer.

var watchID = navigator.accelerometer.watchAcceleration(accelerometerSuccess,
                                                       accelerometerError,
                                                       accelerometerOptions);

• accelerometerOptions: An object with the following optional keys:
  • frequency: requested frequency of calls to accelerometerSuccess with acceleration data in Milliseconds. (Number) (Default: 10000)

Example

function onSuccess(acceleration) {
    alert('Acceleration X: ' + acceleration.x + '\n' +
          'Acceleration Y: ' + acceleration.y + '\n' +
          'Acceleration Z: ' + acceleration.z + '\n' +
          'Timestamp: '      + acceleration.timestamp + '\n');
}

function onError() {
    alert('onError!');
}

var options = { frequency: 3000 };  // Update every 3 seconds

var watchID = navigator.accelerometer.watchAcceleration(onSuccess, onError, options);

iOS Quirks

The API calls the success callback function at the interval requested, but restricts the range of requests to the device between 40ms and 1000ms. For example, if you request an interval of 3 seconds, (3000ms), the API requests data from the device every 1 second, but only executes the success callback every 3 seconds.

navigator.accelerometer.clearWatch

Stop watching the Acceleration referenced by the watchID parameter.

navigator.accelerometer.clearWatch(watchID);

• watchID: The ID returned by navigator.accelerometer.watchAcceleration.

Example

var watchID = navigator.accelerometer.watchAcceleration(onSuccess, onError, options);

// ... later on ...

navigator.accelerometer.clearWatch(watchID);

Acceleration

Contains Accelerometer data captured at a specific point in time. Acceleration values include the effect of gravity (9.81 m/s^2), so that when a device lies flat and facing up, x, y, and z values returned should be 0, 0, and 9.81.

Properties

• x: Amount of acceleration on the x-axis. (in m/s^2) (Number)
• y: Amount of acceleration on the y-axis. (in m/s^2) (Number)
• z: Amount of acceleration on the z-axis. (in m/s^2) (Number)
• timestamp: Creation timestamp in milliseconds. (DOMTimeStamp)