Android Sensor Basics

Base part sensor type

Motion sensor

These sensors measure acceleration and angle of rotation on three axes (X, Y, Z). Several sensors are included.

Acceleration (accelerometer) sensor

Gyroscope (gyroscope) sensor

Gravity (Gravity) sensor

Linear acceleration (linear acceleration) sensor

Rotation vector (rotational vector) sensor

Environmental sensors

These sensors measure parameters in different environments, such as ambient air temperature and pressure, light intensity and humidity. Several sensors are included.

Temperature (Barometer) sensor

Light (photometer) sensor

Temperature (thermometer) sensor

Pressure (pressure) sensor

Position sensor

This type of sensor can measure the physical location of the device. Several sensors are included.

Direction (orientation) sensor (data from acceleration sensors and magnetic field sensors)

magnetic field (Magnetomenter) sensor

Android Sensor type

Type_accelerometer//Acceleration sensor (hardware)

Type_magnetic_field//magnetic field sensor (hardware)

Type_orientation//Direction sensor (software sensor, data from gravity and magnetic field sensors)

Type_gyroscope//Gyroscope sensor (hardware)

Type_light//light sensor (hardware)

Type_pressure//Pressure sensor (hardware)

Type_proximity//Proximity sensor (hardware)

Type_gravity//heavy-field sensors (hardware or software)

Type_linear_acceleration//Linear acceleration sensor (hardware or software)

Type_rotation_vector//rotational vector sensor (hardware or software)

Type_relative_humidity//humidity sensor (hardware)

Type_ambient_temperature//temperature sensor (hardware)

Type_temperature//temperature sensor (hardware), replaced by Type_ambient_temperature starting from Android4.0

Android Sensor parameters

Sensor Callback Frequency

Parameters	Delay Time
Sensormanager.sensor_delay_fastest	0ms
Sensormanager.sensor_delay_game	20ms
sensormanager.sensor_delay_ui	60ms
Sensormanager.sensor_delay_normal	200ms

Sensor return value @link

Acceleration Sensing Detection--accelerometer

Accelerometer sensor measures the negative value (including the gravitational acceleration) of the acceleration generated by all forces exerted on the device. The unit used for acceleration is m/sec^2, and the value is the negative value of the acceleration.

SENSOREVENT.VALUES[0]: Negative value of acceleration on X-axis

SENSOREVENT.VALUES[1]: Negative value of acceleration in Y-axis

SENSOREVENT.VALUES[2]: Negative value of acceleration in z-axis

For example:

The acceleration on the x-axis is positive when the phone's z-axis is flat on the desktop and the phone is pushed from left to right.

When the phone's z-axis is stationary on the desktop, the acceleration of the z-axis is +9.81m/sec^2.

When the phone is falling free from the air, the acceleration is 0.

When the cell phone upward with am/sec^2 acceleration to the air, this time the acceleration is a+9.81m/sec^2

Gravitational acceleration Sensing detection--gravity

The gravitational acceleration, whose units are m/sec^2, is consistent with the accelerometer use. When the phone is stationary, the value of the gravity is consistent with the value of the accelerometer.

Linear Acceleration Sensing detection--linear-acceleration

The relationship between Accelerometer, Gravity and Linear-acceleration is as follows:

Accelerometer = Gravity + linear-acceleration

Ground magnetic field sensing detection--magnetic-field

The unit of the geomagnetic field is Micro-tesla (UT), which detects an absolute magnetic field on the X, Y, Z axes.

Gyro Sensing Detection--gyroscope

The gyroscope is in radians per second, measuring the angular velocity of the object rotating around the x, Y, Z axes. Its coordinate system is the same as the acceleration sensor's coordinate system. The angle of rotation counterclockwise is positive. That is, if the device is rotated counterclockwise, the observer will look at the square of the x, Y, Z axis and report that the device is turning. Note that this is the standard mathematical definition of positive rotation.

Light Sensing Detection--light

Values[0]: Indicates the level of ambient illumination, in SI lux units.

Position approximation Sensing detection--proximity

Values[0]: Approximate distance, in cm (cm) units. Some sensors can only support near and far two states, in which case the sensor must report its Maximum_range value in the far state and the small value in the near state.

Rotational vector sensing detects--rotation vectors

The rotation vector is used to represent the direction of the device, which is made up of angles and axes, or the device rotates the θ angle around one of the x, Y, Z axes. The three elements of the rotation vector are so that the size of the rotation vector equals sin (Θ/2), and the direction of the rotation vector equals the direction of the axis of rotation.

Values[0]: X*sin (Θ/2)

VALUES[1]: Y*sin (Θ/2)

VALUES[2]: Z*sin (Θ/2)

VALUES[3]: cos (Θ/2) (optional:only if value.length = 4)

Direction Sensing Detection--orientation

Its unit is angle

Values[0]: Azimuth (azimuth), the angle of the geomagnetic North direction and the Y axis, rotating around the Z axis (0 to 359). 0=north, 90=east, 180=south, 270=west

VALUES[1]: Pitch (pitch), rotating around x-axis ( -180 to 180), positive when z-axis is moving to y-axis

VALUES[2]: Roll (rolling), rotating around the y-axis ( -90 to 90), positive when the x-axis moves to the z-axis

Api:

Get system support sensor type/*** Support Sensor list *http://blog.csdn.net/redoq/article/details/52515123     *  https://zhidao.baidu.com/question/2205380242168742428.html     *  http://www.jianshu.com/p/4c141d851346     */    Private voidtestsupportsensorlist () {Sensormanager Sensormanager=(Sensormanager) Getsystemservice (Sensor_service); String Sensorstr= ""; List<Sensor> list =sensormanager.getsensorlist (Sensor.type_all);  for(Sensor sensor:list) {sensorstr+ = Sensor.getname () + "\ n";        } xlog.i (SENSORSTR); Sensorstr= "";  for(Sensor sensor:list) {Switch(Sensor.gettype ()) { CaseSensor.TYPE_ACCELEROMETER:sensorStr+ = "Acceleration sensor" + "\ n";  Break;  CaseSensor.TYPE_MAGNETIC_FIELD:sensorStr+ = "magnetic field sensor" + "\ n";  Break;  CaseSensor.TYPE_ORIENTATION:sensorStr+ = "Direction sensor" + "\ n";  Break;  CaseSensor.TYPE_GYROSCOPE:sensorStr+ = "Gyro sensor" + "\ n";  Break;  CaseSensor.TYPE_LIGHT:sensorStr+ = "Light sensor" + "\ n";  Break;  CaseSensor.TYPE_PRESSURE:sensorStr+ = "Pressure sensor" + "\ n";  Break;  CaseSensor.TYPE_PROXIMITY:sensorStr+ = "Proximity sensor" + "\ n";  Break;  CaseSensor.TYPE_GRAVITY:sensorStr+ = "heavy field sensor" + "\ n";  Break;  CaseSensor.TYPE_LINEAR_ACCELERATION:sensorStr+ = "linear acceleration sensor" + "\ n";  Break;  CaseSensor.TYPE_ROTATION_VECTOR:sensorStr+ = "rotational vector sensor" + "\ n";  CaseSensor.TYPE_RELATIVE_HUMIDITY:sensorStr+ = "Humidity sensor" + "\ n";  Break;  CaseSensor.TYPE_AMBIENT_TEMPERATURE:sensorStr+ = "Temperature sensor" + "\ n";  Break;  CaseSensor.TYPE_TEMPERATURE:sensorStr+ = "Temperature sensor" + "\ n";  Break; }} xlog.i (SENSORSTR);} The sensor uses the steps (general) S1, before using the sensor to obtain the Sensormanager through the system service get: Sensormanager Msensormanager=(Sensormanager) Getsystemservice (sensor_service); S2, get the type of sensor we need://one-time effective step countSensor Mstepcount =msensormanager.getdefaultsensor (sensor.type_step_counter);//System Count Step cumulative valueSensor Mstepdetector =msensormanager.getdefaultsensor (Sensor.type_step_detector); S3, Register Listener (monitor sensor event) Msensormanager.registerlistener ( This, Mstepdetector, sensormanager.sensor_delay_fastest); Msensormanager.registerlistener ( This, Mstepcount, sensormanager.sensor_delay_fastest); PS: Cancel Registration: Msensormanager.unregisterlistener ( This, Mstepdetector); Msensormanager.unregisterlistener ( This, Mstepcount), S4, implement Sensoreventlistener interface, override method, and get data @override Public voidOnsensorchanged (Sensorevent event)

Reference:

http://blog.csdn.net/mad1989/article/details/20848181

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