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cordova-plugin-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 awatchAccelerometer
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)