Android

The accelerometer measures the acceleration applied to the sensor built-in into the device, including the force of gravity. In other words, the force of gravity is always influencing the measured acceleration, thus when the device is sitting on a table, the accelerometer reads the acceleration of gravity: 9.81 m/s². Similarly, if the phone is in free-fall towards the ground, the accelerometer reads: 0 m/s².

The coordinate-system is defined relative to the screen of the phone in its default orientation (facing the user). The axis are not swapped when the device’s screen orientation changes. The X axis is horizontal and points to the right, the Y axis is vertical and points up and the Z axis points towards the outside of the front face of the screen. In this system, coordinates behind the screen have negative Z axis. Also, the natural orientation of a device is not always portrait, as the natural orientation for many tablet devices is landscape. For more information, check the official Android’s Sensor Coordinate System documentation.

Public functions

• Accelerometer.getFrequency( Context context ): returns sampling rate in Hz.

Settings

• Aware_Preferences.STATUS_ACCELEROMETER: true or false to activate or deactivate accelerometer sensor.
• Aware_Preferences.FREQUENCY_ACCELEROMETER: non-deterministic frequency in microseconds (dependent of the hardware sensor capabilities and resources), e.g., 200000 (normal), 60000 (UI), 20000 (game), 0 (fastest).

• Accelerometer.ACTION_AWARE_ACCELEROMETER: new data recorded in provider.
  • Accelerometer.EXTRA_DATA: the recorded data, as ContentValues.
• Accelerometer.ACTION_AWARE_ACCELEROMETER_LABEL: send this broadcast to assign a label to the ongoing recording of data.
  • Accelerometer.EXTRA_LABEL: the desired label.

Accelerometer Sensor

Contains the hardware sensor capabilities in the mobile device.

Accelerometer_Sensor.CONTENT_URI
content://com.aware.provider.accelerometer/sensor_accelerometer

Table field	Field type	Description
_id	INTEGER	primary key, auto incremented
timestamp	REAL	unixtime milliseconds since 1970
device_id	TEXT	AWARE device UUID
double_sensor_maximum_range	REAL	Maximum sensor value possible
double_sensor_minimum_delay	REAL	Minimum sampling delay in microseconds
sensor_name	TEXT	Sensor’s name
double_sensor_power_ma	REAL	Sensor’s power drain in mA
double_sensor_resolution	REAL	Sensor’s resolution in sensor’s units
sensor_type	TEXT	Sensor’s type
sensor_vendor	TEXT	Sensor’s manufacturer
sensor_version	TEXT	Sensor’s version number

Accelerometer Data

Contains the raw sensor data.

Accelerometer_Data.CONTENT_URI
content://com.aware.provider.accelerometer/accelerometer