# Titanium.Accelerometer

> The top-level Accelerometer module, used to determine the device's physical position.

- Source: https://titaniumsdk.com/docs/sdk/12.7.1/Titanium.Accelerometer
- Titanium SDK version: 12.7.1
- Kind: module
- Platforms: Android, iPhone, iPad, macOS
- Since: Titanium SDK 0.1
- Extends: Titanium.Module
- Inheritance: Titanium.Module > Titanium.Proxy

An accelerometer is a hardware unit integrated into a mobile device, that detects when the 
device has moved, and returns its new orientation in a three-dimensional space. With its 
single `update` event, this module provides an interface to access the output positional data.

An accelerometer needs to be switched on in order for it to report to the operating system, 
which consumes a lot of power that will deplete the battery over time. This is why it is 
recommended that the accelerometer is switched off when not in use.

The accelerometer may be switched on and off by simply adding and removing the `update` 
event listener function. See the example for a demonstration.

## Example: Basic Accelerometer Event

Adds an accelerometer update event listener, and displays the x, y and z axis in the 
window when the device is moved. On Android, the accelerometer is switched off and on when 
the application is paused and resumed.

``` js
var win = Ti.UI.createWindow({
  backgroundColor: 'white',
  exitOnClose:true,
  layout: 'vertical'
});

opts = {
  color:'black',
  font:{fontSize:20},
  text:'-',
  top:20, left:10,
  width:300
};
var labelTimestamp = Ti.UI.createLabel(opts);
win.add(labelTimestamp);
var labelx = Ti.UI.createLabel(opts);
win.add(labelx);
var labely = Ti.UI.createLabel(opts);
win.add(labely);
var labelz = Ti.UI.createLabel(opts);
win.add(labelz);
win.open();

var accelerometerCallback = function(e) {
  labelTimestamp.text = 'timestamp: ' + e.timestamp;
  labelx.text = 'x: ' + e.x;
  labely.text = 'y: ' + e.y;
  labelz.text = 'z: ' + e.z;
};

if (Ti.Platform.model === 'Simulator' || Ti.Platform.model.indexOf('sdk') !== -1 ) {
  alert('Accelerometer does not work on a virtual device');
} else {
  Ti.Accelerometer.addEventListener('update', accelerometerCallback);
  if (Ti.Platform.name === 'android') {
    win.addEventListener("open", function(e) {
      win.activity.addEventListener("pause", function() {
        Ti.API.info("removing accelerometer callback on pause");
        Ti.Accelerometer.removeEventListener('update', accelerometerCallback);
      });
      win.activity.addEventListener("resume", function() {
        Ti.API.info("adding accelerometer callback on resume");
        Ti.Accelerometer.addEventListener('update', accelerometerCallback);
      });
    });
  }
}
```

## Events

### update

- Platforms: Android, iPhone, iPad, macOS

Fired when the accelerometer changes.

Event properties:

- `timestamp` (Number): Reference timestamp since the previous change. This is not a valid timestamp and should simply be used to determine the number of milliseconds between events.
- `y` (Number): Current `y` axis of the device.
- `x` (Number): Current `x` axis of the device.
- `z` (Number): Current `z` axis of the device.

## Inherited members

7 members are inherited. Each is documented on the type that declares it.

- [Titanium.Proxy](https://titaniumsdk.com/docs/sdk/12.7.1/Titanium.Proxy.md): `addEventListener`, `apiName`, `applyProperties`, `bubbleParent`, `fireEvent`, `lifecycleContainer`, `removeEventListener`

---

- This corpus documents Titanium SDK 13.4.1. Anything here that does not name a version describes 13.4.1.
- Titanium is maintained by TiDev. The Appcelerator toolchain is retired: there is no `appc` CLI, no Appcelerator Studio and no hosted build service. The supported CLI is `titanium` on npm, invoked as `ti`.