Sensor

Tizen provides functions for receiving and managing sensor data.

The main features of the Sensor API include:

Sensor Handle
Sensor Listener

Note
Not all devices support all sensor types. For more information, see System Information.

Sensor Handle

A device can have various physical sensors. Tizen supports the following sensor types:

Accelerometer Sensor
Gravity Sensor
Linear Accelerometer Sensor
Magnetic Sensor
Rotation Vector Sensor
Orientation Sensor
Gyroscope Sensor
Light Sensor
Proximity Sensor
Pressure Sensor
Ultraviolet Sensor
Temperature Sensor
Humidity Sensor
HRM Sensor
HRM LED Green Sensor
HRM LED IR Sensor
HRM LED Red Sensor

The Sensor API enables your application to receive data from the device's internal sensors. The application can receive the sensor data only when the data is modified.

Note
Not all sensors are available on all devices.

The Sensor API finds sensors, and monitors their availability. Key sensor features provided by the Sensor API include getting and setting the following:

Sensor name
Sensor vendor
Sensor type
Resolution
Sensing interval
Measurement range

Accelerometer Sensor

The accelerometer sensor measures changes in velocity. It can also be used to determine orientation. The accelerometer sensor measures the device's accelerometer vector in 3 axes relative to its body frame.

Note
An acceleration shift of 1g always exists due to gravity. You must compensate for the gravitational pull of the Earth to detect device movement by subtracting the gravity offset. If the device is at rest, or the device is falling and has reached terminal velocity, the sensor data reads 1g (the gravity offset) and tells you the direction of gravity.

The accelerometer sensor provides 3 components of acceleration (X, Y, and Z), as the following figure illustrates.

Figure: Accelerometer sensor vector and axes

Accelerometer sensor vector and axes

The accelerometer sensor outputs 4 values: 3 Cartesian axis values and a timestamp. The accelerometer sensor measures and returns axes values in "m/s²" (meters per second squared). When a device is accelerated in the ±X, ±Y, or ±Z direction, the corresponding output increases (+) or decreases (-).

The following table lists the measurement data that the accelerometer sensor provides.

Table: Measurement data detected by the accelerometer sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: X	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[1]: Y	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[2]: Z	float	Min. value = -19.6 Max. value = 19.6	m/s²

The following table provides information about the accelerometer sensor output for a device at rest.

Table: Acceleration sensor output for a device at rest
Position	1	2	3	4	5	6
Diagram
values[0]: X	0g	1g	0g	-1g	0g	0g
values[1]: Y	1g	0g	-1g	0g	0g	0g
values[2]: Z	0g	0g	0g	0g	1g	-1g
Axis up (down)	Y	X	-Y	-X	Z	-Z
X-polarity	0	+	0	-	0	0
Y-polarity	+	0	-	0	0	0
Z-polarity	0	0	0	0	+	-

Gravity Sensor

The gravity sensor is originated from the 3-axis acceleration sensor. It measures the vector components of gravity when the device is at rest or moving slowly. The gravity sensor can be used, for example, with game controls using tilting motion.

The gravity sensor provides 3 components of acceleration (X, Y, and Z), as the following figure illustrates.

Figure: Gravity sensor vector and axes

Gravity sensor vector and axes

Gravity is a unit vector (scalar = 1). The gravity sensor outputs 4 values: 3 Cartesian axis values and a timestamp. The gravity sensor measures and returns axes values in "m/s²" (meters per second squared). When a device is accelerated in the ±X, ±Y, or ±Z direction, the corresponding output increases (+) or decreases (-).

Accelerometer changes generated by gravity are sensed in opposite directions.

The following table lists the measurement data that the gravity sensor provides.

Table: Measurement data detected by the gravity sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: X	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[1]: Y	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[2]: Z	float	Min. value = -19.6 Max. value = 19.6	m/s²

Linear Accelerometer Sensor

The linear accelerometer sensor measures user-driven changes in velocity without considering the gravity value. It measures the device's accelerometer vector in 3 axes relative to its body frame. The linear accelerometer sensor is used to detect the dynamic movement of the device and analyze the user's motion profile.

The linear accelerometer sensor provides 3 components of acceleration (X, Y, and Z), as the following figure illustrates.

Figure: User-acceleration sensor vector and axes

User-acceleration sensor vector and axes

The linear accelerometer sensor outputs 4 values: 3 Cartesian axis values and a timestamp. The linear accelerometer sensor measures and returns axes values in "m/s²" (meters per second squared). When a device is accelerated in the ±X, ±Y, or ±Z direction, the corresponding output increases (+) or decreases (-). The accelerometer output is shown in the same direction as the user-driven force.

Accelerometer changes generated by user-driven force are sensed in opposite directions.

The following table lists the measurement data that the linear accelerometer sensor provides.

Table: Measurement data detected by the linear accelerometer sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: X	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[1]: Y	float	Min. value = -19.6 Max. value = 19.6	m/s²
values[2]: Z	float	Min. value = -19.6 Max. value = 19.6	m/s²

Magnetic Sensor

The magnetic sensor is a 3-axis electronic compass (sometimes referred to as a "magnetometer"). It can also be used in determining orientation. The magnetic sensor measures magnetic field strength and fluctuations, and splits the measurement into X, Y, and Z components. Note that the following factors can have an impact on the readings:

The weather or the season of the year
Your location on the planet
Nearby, strong magnetic fields, such as magnets or electric coils

The following table lists the measurement data that the magnetic sensor provides.

Table: Measurement data detected by the magnetic sensor
Measurement	Type	Unit
Timestamp	long	Milliseconds
values[0]: X	float	μT (micro Tesla)
values[1]: Y	float	μT (micro Tesla)
values[2]: Z	float	μT (micro Tesla)

The magnetic sensor uses the body of the device as a fixed frame of reference. It also uses the 3-axis Cartesian space coordinate system, as the following figure illustrates.

Figure: Magnetic field vector and axes

Magnetic field vector and axes

Rotation Vector Sensor

The rotation vector sensor represents the orientation of the device as a combination of an angle and an axis, in which the device has rotated through a specific angle around an axis (x, y, or z).

The following table lists the measurement data that the rotation vector sensor provides.

Table: Measurement data detected by the rotation vector
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
Accuracy	sensor_data_accuracy_e	-	int
values[0]: X	float	Min. value = -1 Max. value = 1	-
values[1]: Y	float	Min. value = -1 Max. value = 1	-
values[2]: Z	float	Min. value = -1 Max. value = 1	-
values[3]: W	float	Min. value = -1 Max. value = 1	-

Orientation Sensor

The orientation sensor combines the 3-axis accelerometer sensor and 3-axis magnetic sensor to determine the following angular positions:

Azimuth
Pitch
Roll

The following table lists the measurement data that the orientation sensor provides.

Table: Measurement data detected by the orientation sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: Azimuth	float	Min. value = 0 Max. value = 360	Degrees (°)
values[1]: Pitch	float	Min. value = -180 Max. value = 180	Degrees (°)
values[2]: Roll	float	Min. value = -90 Max. value = 90	Degrees (°)

The angular positions are measured using a fixed frame reference (X_E, Y_E, Z_E).

Figure: Angular positions and the fixed frame reference

Angular positions and the fixed frame reference

Gyroscope Sensor

The gyroscope sensor detects angular velocity, which is calculated using the measurement data retrieved from a 3-axis gyroscope.

Figure: Gyroscope sensor vector and axes

Gyroscope sensor vector and axes

The following table lists the measurement data that the gyroscope sensor provides.

Table: Measurement data detected by the gyroscope sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: X	float	Min. value = -573.0 Max. value = 573.0	Degrees/s (°/s)
values[1]: Y	float	Min. value = -573.0 Max. value = 573.0	Degrees/s (°/s)
values[2]: Z	float	Min. value = -573.0 Max. value = 573.0	Degrees/s (°/s)

Light Sensor

The light sensor detects the brightness of ambient light. It can be used to measure the brightness level.

Use the light sensor to control the brightness of the screen. For example, if you are in a dark environment, the light sensor detects the brightness of the environment and increases the device screen backlight brightness level. In a brighter environment, the backlight brightness level is lowered to save battery power.

The following table lists the measurement data that the light sensor provides.

Table: Measurement data detected by the light sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: Level	float	Min. value = 0 Max. value = 45875	Lux

Proximity Sensor

The proximity sensor detects the presence of nearby objects. It can be used to measure the distance between nearby objects and the device.

Use the proximity sensor to lock or unlock the device screen. For example, when the device user holds the device to their ear, the proximity sensor detects the user as an object, and automatically locks the device screen. When the user moves the device away from their ear to input data, the proximity sensor determines that there are no nearby objects, and unlocks the screen.

The following table lists the measurement data that the proximity sensor provides.

Table: Measurement data detected by the proximity sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: proximity	float	-	-

Pressure Sensor

The pressure sensor measures pressure, typically the pressure of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and it is usually stated in terms of force per unit area. A pressure sensor usually acts as a transducer, generating a signal as a function of the pressure imposed. For the purposes of Tizen, the signal is electrical.

Measurement values are related to the sensor type.

The following table lists the measurement data that the pressure sensor provides.

Table: Measurement data detected by the pressure sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: pressure	float	Min. value = 260 Max. value = 1260	hPa

Ultraviolet Sensor

The ultraviolet sensor measures the ultraviolet index.

The following table lists the measurement data that the ultraviolet sensor provides.

Table: Measurement data detected by the ultraviolet sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: uv index	float	Min. value = 0 Max. value = 15	uv index

Temperature Sensor

The temperature sensor measures the temperature, just like a thermometer.

The following table lists the measurement data that the temperature sensor provides.

Table: Measurement data detected by the temperature sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: temperature	float	Min. value = -30 Max. value = 100	℃

Humidity Sensor

The humidity sensor measures humidity.

The following table lists the measurement data that the humidity sensor provides.

Table: Measurement data detected by the humidity sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: humidity	float	100	%

HRM Sensor

The HRM sensor measures the heart rate in beats per minute.

The following table lists the measurement data that the HRM sensor provides.

Table: Measurement data detected by the HRM sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: beats per minute	int	Min. value = 0 Max. value = 220	-

HRM LED Green Sensor

The HRM LED green sensor measures the amount of green light that is reflected from a blood vessel.

The following table lists the measurement data that the HRM LED green sensor provides.

Table: Measurement data detected by the HRM LED green sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: HRM green light	int	Min. value = 0 Max. value = 1081216	-

HRM LED IR Sensor

The HRM LED IR sensor measures the amount of infrared light that is reflected from a blood vessel.

The following table lists the measurement data that the HRM LED IR sensor provides.

Table: Measurement data detected by the HRM LED IR sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: HRM IR light	int	Min. value = 0 Max. value = 1081216	-

HRM LED Red Sensor

The HRM LED red sensor measures the amount of red light that is reflected from a blood vessel.

The following table lists the measurement data that the HRM LED red sensor provides.

Table: Measurement data detected by the HRM LED red sensor
Measurement	Type	Range	Unit
Timestamp	long	-	Milliseconds
values[0]: HRM red light	int	Min. value = 0 Max. value = 1081216	-

Sensor Listener

The Sensor API detects sensors and monitors their availability. The key sensor listening features provided by the Sensor API include:

Adding and removing sensor listeners
Checking available sensors
Getting sensor data

When running your application on the Emulator, you can use the Event Injector view to provide sensor data for the application.

You can add or remove sensor listeners at any time.

Listeners poll sensors for data and deliver the data to applications at predefined intervals. Applications can add multiple sensor listeners for the same sensor type, but the polling interval must be the same for each sensor listener and within the allowed interval range.