Android P九轴传感器数据读取
16lz
2021-01-23
相关资料：
https://www.st.com/zh/mems-and-sensors/lsm9ds1.html#tools-software
https://github.com/STMicroelectronics/STMems_Android_Sensor_HAL_IIO
https://www.st.com/content/st_com/zh/products/embedded-software/mems-and-sensors-software/drivers-for-mems/androidhal-iio.html
陀螺仪，Gyroscope，GYRO-Sensor，通过测量自身的旋转状态，判断出设备当前运动状态，是向前、向后、向左还是向右，是加速还是减速。
加速度计，Accelerometer，G-Sensor，重力感应器，可以感知任意方向上的加速度，可以感知受力情况。
磁力计，Magnetic，M-Sensor，测试磁场强度和方向，定位设备的方位，可以测量出东南西北四个方位的夹角。
总之，陀螺仪知道我们转了几个圈，加速度计知道我们向前走了几米，磁力计知道我们的方位。
安卓中通过监听SensorEventListener来获取传感器的数据。
事件类型：
import android.hardware.Sensor;public static final String STRING_TYPE_TEMPERATURE = "android.sensor.temperature";public static final int TYPE_ACCELEROMETER = 1; //加速度计public static final int TYPE_ACCELEROMETER_UNCALIBRATED = 35;public static final int TYPE_ALL = -1;public static final int TYPE_AMBIENT_TEMPERATURE = 13;public static final int TYPE_DEVICE_PRIVATE_BASE = 65536;public static final int TYPE_GAME_ROTATION_VECTOR = 15;public static final int TYPE_GEOMAGNETIC_ROTATION_VECTOR = 20;public static final int TYPE_GRAVITY = 9;public static final int TYPE_GYROSCOPE = 4;//陀螺仪public static final int TYPE_GYROSCOPE_UNCALIBRATED = 16;public static final int TYPE_HEART_BEAT = 31;public static final int TYPE_HEART_RATE = 21;public static final int TYPE_LIGHT = 5;public static final int TYPE_LINEAR_ACCELERATION = 10;public static final int TYPE_LOW_LATENCY_OFFBODY_DETECT = 34;public static final int TYPE_MAGNETIC_FIELD = 2;//磁力计public static final int TYPE_MAGNETIC_FIELD_UNCALIBRATED = 14;public static final int TYPE_MOTION_DETECT = 30;注册监听：
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD), SensorManager.SENSOR_DELAY_NORMAL);sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD_UNCALIBRATED), SensorManager.SENSOR_DELAY_NORMAL);sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE), SensorManager.SENSOR_DELAY_NORMAL);完整代码：
public class MainActivity extends AppCompatActivity implements SensorEventListener{ private static final String TAG = "Magnetometer"; private TextView magnetometer_value; private TextView accelerometer_value_X; private TextView accelerometer_value_Y; private TextView accelerometer_value_Z; private TextView gyroscope_value_X; private TextView gyroscope_value_Y; private TextView gyroscope_value_Z; private SensorManager sensorManager; public static DecimalFormat DECIMAL_FORMATTER; //Accelerometer float[] accelerometerValues = new float[3]; float[] gravity = new float[3]; float[] linear_acceleration = new float[3]; float[] magneticValues = new float[3]; //Gyroscope private static final float NS2S = 1.0f / 1000000000.0f; private final float[] deltaRotationVector = new float[4]; private float timestamp; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Log.i(TAG,"Magnetometer,onCreate"); magnetometer_value = (TextView) findViewById(R.id.magnetometer_value); accelerometer_value_X = (TextView) findViewById(R.id.accelerometer_value_X); accelerometer_value_Y = (TextView) findViewById(R.id.accelerometer_value_Y); accelerometer_value_Z = (TextView) findViewById(R.id.accelerometer_value_Z); gyroscope_value_X = (TextView) findViewById(R.id.gyroscope_value_X); gyroscope_value_Y = (TextView) findViewById(R.id.gyroscope_value_Y); gyroscope_value_Z = (TextView) findViewById(R.id.gyroscope_value_Z); // define decimal formatter DecimalFormatSymbols symbols = new DecimalFormatSymbols(Locale.US); symbols.setDecimalSeparator('.'); DECIMAL_FORMATTER = new DecimalFormat("#.#", symbols); sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); if (sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD) != null){ // Success! There's a magnetometer. Log.i(TAG,"Magnetometer,Success! There's a magnetometer."); } else { // Failure! No magnetometer. Log.i(TAG,"Magnetometer,Failure! No magnetometer."); } } @Override protected void onResume() { super.onResume(); Log.i(TAG,"Magnetometer,onResume"); if (sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD) != null){ // Success! There's a magnetometer. Log.i(TAG,"Magnetometer,Success! There's a magnetometer."); } else { // Failure! No magnetometer. Log.i(TAG,"Magnetometer,Failure! No magnetometer."); } sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD), SensorManager.SENSOR_DELAY_NORMAL); sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD_UNCALIBRATED), SensorManager.SENSOR_DELAY_NORMAL); sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL); sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE), SensorManager.SENSOR_DELAY_NORMAL); } @Override protected void onPause() { super.onPause(); sensorManager.unregisterListener(this); } @Override public void onSensorChanged(SensorEvent event) { //Log.i(TAG,"onSensorChanged,event=" + event); if ( event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD ) { Log.i(TAG,"onSensorChanged,TYPE_MAGNETIC_FIELD"); // get values for each axes X,Y,Z float magX = event.values[0]; float magY = event.values[1]; float magZ = event.values[2]; double magnitude = Math.sqrt((magX * magX) + (magY * magY) + (magZ * magZ)); // set value on the screen magnetometer_value.setText( DECIMAL_FORMATTER.format(magnitude) + " \u00B5Tesla"); }else if( event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD_UNCALIBRATED ){ Log.i(TAG,"onSensorChanged,TYPE_MAGNETIC_FIELD"); }else if( event.sensor.getType() == Sensor.TYPE_ACCELEROMETER ){ //Log.i(TAG,"onSensorChanged,TYPE_ACCELEROMETER"); accelerometerValues = event.values.clone(); // alpha is calculated as t / (t + dT) // with t, the low-pass filter's time-constant // and dT, the event delivery rate final float alpha = 0.8f; gravity[0] = alpha * gravity[0] + (1 - alpha) * event.values[0]; gravity[1] = alpha * gravity[1] + (1 - alpha) * event.values[1]; gravity[2] = alpha * gravity[2] + (1 - alpha) * event.values[2]; linear_acceleration[0] = event.values[0] - gravity[0]; linear_acceleration[1] = event.values[1] - gravity[1]; linear_acceleration[2] = event.values[2] - gravity[2]; accelerometer_value_X.setText(DECIMAL_FORMATTER.format( accelerometerValues[0])); accelerometer_value_Y.setText(DECIMAL_FORMATTER.format( accelerometerValues[1])); accelerometer_value_Z.setText(DECIMAL_FORMATTER.format( accelerometerValues[2])); }else if( event.sensor.getType() == Sensor.TYPE_GYROSCOPE ){ // This time step's delta rotation to be multiplied by the current rotation // after computing it from the gyro sample data. if (timestamp != 0) { final float dT = (event.timestamp - timestamp) * NS2S; // Axis of the rotation sample, not normalized yet. float axisX = event.values[0]; float axisY = event.values[1]; float axisZ = event.values[2]; // Calculate the angular speed of the sample float omegaMagnitude = (float)Math.sqrt(axisX*axisX + axisY*axisY + axisZ*axisZ); // Normalize the rotation vector if it's big enough to get the axis if (omegaMagnitude > EPSILON) { axisX /= omegaMagnitude; axisY /= omegaMagnitude; axisZ /= omegaMagnitude; } // Integrate around this axis with the angular speed by the time step // in order to get a delta rotation from this sample over the time step // We will convert this axis-angle representation of the delta rotation // into a quaternion before turning it into the rotation matrix. float thetaOverTwo = omegaMagnitude * dT / 2.0f; float sinThetaOverTwo = (float)Math.sin(thetaOverTwo); float cosThetaOverTwo = (float)Math.cos(thetaOverTwo); deltaRotationVector[0] = sinThetaOverTwo * axisX; deltaRotationVector[1] = sinThetaOverTwo * axisY; deltaRotationVector[2] = sinThetaOverTwo * axisZ; deltaRotationVector[3] = cosThetaOverTwo; gyroscope_value_X.setText( DECIMAL_FORMATTER.format( axisX)); gyroscope_value_Y.setText( DECIMAL_FORMATTER.format( axisY)); gyroscope_value_Z.setText( DECIMAL_FORMATTER.format( axisZ)); } timestamp = event.timestamp; float[] deltaRotationMatrix = new float[9]; SensorManager.getRotationMatrixFromVector(deltaRotationMatrix, deltaRotationVector); // User code should concatenate the delta rotation we computed with the current // rotation in order to get the updated rotation. // rotationCurrent = rotationCurrent * deltaRotationMatrix; } } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { Log.i(TAG,"onSensorChanged,sensor=" + sensor); Log.i(TAG,"onSensorChanged,accuracy=" + accuracy); }}