The reporting modes of sensors

Sensors can generate events in different ways called reporting modes. Each sensor has a particular type of reporting mode. The reporting mode is an Integer constant of the Sensor class, which can be obtained using the getReportingMode() method of the Sensor object. Knowing the reporting mode of a sensor can help developers write an efficient logic. Reporting modes can be categorized into following four types:

• Continuous: In continuous reporting mode, the sensor events are generated at a constant rate defined by the sampling period. This sampling period is set at the time of registering the listener for the sensor. For example, the sensors using the continuous reporting mode are the accelerometer and gyroscope.
• On Change: In the on-change reporting mode, the sensor events are generated only if the measured values have changed from the last known values. For example, sensors using the on-change reporting mode are the step counter, proximity, and heart rate sensors.
• One Shot: The one shot reporting mode is based on the fire and forget concept. They are triggered only once in the entire duration of the event. The significant motion sensor uses the one shot reporting mode to notify the event. It is only fired once, when the sensor detects the start of significant motion because of walking, running, or driving.
• Special Trigger: The special trigger is fired on each occurrence of a particular event. Upon the detection of an event, the sensor values are generated and passed to the listener. The sampling period is ignored in this case. The step detector sensor is an example of the special trigger reporting mode, which is fired on every step taken.