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Thrifty Motion Sensor

11 December 2020

Olivier Le Goaer

android

java

kotlin

The rotation vector sensor is the most frequently used sensor for motion detection and monitoring. When using SensorManager#getDefaultSensor(int type), always prefer the constant TYPE_GEOMAGNETIC_ROTATION_VECTOR which is similar to TYPE_ROTATION_VECTOR, but using a magnetometer instead of using a gyroscope. This sensor uses lower power than the other rotation vectors, because it doesn't use the gyroscope. However, it is more noisy and will work best outdoors.

Noncompliant Code

private SensorManager sensorManager;
private Sensor sensor;
...
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);

Compliant Solution

private SensorManager sensorManager;
private Sensor sensor;
...
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
sensor = sensorManager.getDefaultSensor(Sensor.TYPE_GEOMAGNETIC_ROTATION_VECTOR);