| /* |
| * Copyright (C) 2008 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.hardware; |
| |
| import android.annotation.UnsupportedAppUsage; |
| |
| /** |
| * This class represents a {@link android.hardware.Sensor Sensor} event and |
| * holds information such as the sensor's type, the time-stamp, accuracy and of |
| * course the sensor's {@link SensorEvent#values data}. |
| * |
| * <p> |
| * <u>Definition of the coordinate system used by the SensorEvent API.</u> |
| * </p> |
| * |
| * <p> |
| * The coordinate-system is defined relative to the screen of the phone in its |
| * default orientation. The axes are not swapped when the device's screen |
| * orientation changes. |
| * </p> |
| * |
| * <p> |
| * The X axis is horizontal and points to the right, the Y axis is vertical and |
| * points up and the Z axis points towards the outside of the front face of the |
| * screen. In this system, coordinates behind the screen have negative Z values. |
| * </p> |
| * |
| * <p> |
| * <center><img src="../../../images/axis_device.png" |
| * alt="Sensors coordinate-system diagram." border="0" /></center> |
| * </p> |
| * |
| * <p> |
| * <b>Note:</b> This coordinate system is different from the one used in the |
| * Android 2D APIs where the origin is in the top-left corner. |
| * </p> |
| * |
| * @see SensorManager |
| * @see SensorEvent |
| * @see Sensor |
| * |
| */ |
| |
| public class SensorEvent { |
| /** |
| * <p> |
| * The length and contents of the {@link #values values} array depends on |
| * which {@link android.hardware.Sensor sensor} type is being monitored (see |
| * also {@link SensorEvent} for a definition of the coordinate system used). |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_ACCELEROMETER |
| * Sensor.TYPE_ACCELEROMETER}:</h4> All values are in SI units (m/s^2) |
| * |
| * <ul> |
| * <li> values[0]: Acceleration minus Gx on the x-axis </li> |
| * <li> values[1]: Acceleration minus Gy on the y-axis </li> |
| * <li> values[2]: Acceleration minus Gz on the z-axis </li> |
| * </ul> |
| * |
| * <p> |
| * A sensor of this type measures the acceleration applied to the device |
| * (<b>Ad</b>). Conceptually, it does so by measuring forces applied to the |
| * sensor itself (<b>Fs</b>) using the relation: |
| * </p> |
| * |
| * <b><center>Ad = - ∑Fs / mass</center></b> |
| * |
| * <p> |
| * In particular, the force of gravity is always influencing the measured |
| * acceleration: |
| * </p> |
| * |
| * <b><center>Ad = -g - ∑F / mass</center></b> |
| * |
| * <p> |
| * For this reason, when the device is sitting on a table (and obviously not |
| * accelerating), the accelerometer reads a magnitude of <b>g</b> = 9.81 |
| * m/s^2 |
| * </p> |
| * |
| * <p> |
| * Similarly, when the device is in free-fall and therefore dangerously |
| * accelerating towards to ground at 9.81 m/s^2, its accelerometer reads a |
| * magnitude of 0 m/s^2. |
| * </p> |
| * |
| * <p> |
| * It should be apparent that in order to measure the real acceleration of |
| * the device, the contribution of the force of gravity must be eliminated. |
| * This can be achieved by applying a <i>high-pass</i> filter. Conversely, a |
| * <i>low-pass</i> filter can be used to isolate the force of gravity. |
| * </p> |
| * |
| * <pre class="prettyprint"> |
| * |
| * public void onSensorChanged(SensorEvent event) |
| * { |
| * // 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 = 0.8; |
| * |
| * 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]; |
| * } |
| * </pre> |
| * |
| * <p> |
| * <u>Examples</u>: |
| * <ul> |
| * <li>When the device lies flat on a table and is pushed on its left side |
| * toward the right, the x acceleration value is positive.</li> |
| * |
| * <li>When the device lies flat on a table, the acceleration value is |
| * +9.81, which correspond to the acceleration of the device (0 m/s^2) minus |
| * the force of gravity (-9.81 m/s^2).</li> |
| * |
| * <li>When the device lies flat on a table and is pushed toward the sky |
| * with an acceleration of A m/s^2, the acceleration value is equal to |
| * A+9.81 which correspond to the acceleration of the device (+A m/s^2) |
| * minus the force of gravity (-9.81 m/s^2).</li> |
| * </ul> |
| * |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_MAGNETIC_FIELD |
| * Sensor.TYPE_MAGNETIC_FIELD}:</h4> |
| * All values are in micro-Tesla (uT) and measure the ambient magnetic field |
| * in the X, Y and Z axis. |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_GYROSCOPE Sensor.TYPE_GYROSCOPE}: |
| * </h4> All values are in radians/second and measure the rate of rotation |
| * around the device's local X, Y and Z axis. The coordinate system is the |
| * same as is used for the acceleration sensor. Rotation is positive in the |
| * counter-clockwise direction. That is, an observer looking from some |
| * positive location on the x, y or z axis at a device positioned on the |
| * origin would report positive rotation if the device appeared to be |
| * rotating counter clockwise. Note that this is the standard mathematical |
| * definition of positive rotation and does not agree with the definition of |
| * roll given earlier. |
| * <ul> |
| * <li> values[0]: Angular speed around the x-axis </li> |
| * <li> values[1]: Angular speed around the y-axis </li> |
| * <li> values[2]: Angular speed around the z-axis </li> |
| * </ul> |
| * <p> |
| * Typically the output of the gyroscope is integrated over time to |
| * calculate a rotation describing the change of angles over the time step, |
| * for example: |
| * </p> |
| * |
| * <pre class="prettyprint"> |
| * private static final float NS2S = 1.0f / 1000000000.0f; |
| * private final float[] deltaRotationVector = new float[4](); |
| * private float timestamp; |
| * |
| * public void onSensorChanged(SensorEvent event) { |
| * // 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 = 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 = sin(thetaOverTwo); |
| * float cosThetaOverTwo = cos(thetaOverTwo); |
| * deltaRotationVector[0] = sinThetaOverTwo * axisX; |
| * deltaRotationVector[1] = sinThetaOverTwo * axisY; |
| * deltaRotationVector[2] = sinThetaOverTwo * axisZ; |
| * deltaRotationVector[3] = cosThetaOverTwo; |
| * } |
| * 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; |
| * } |
| * </pre> |
| * <p> |
| * In practice, the gyroscope noise and offset will introduce some errors |
| * which need to be compensated for. This is usually done using the |
| * information from other sensors, but is beyond the scope of this document. |
| * </p> |
| * <h4>{@link android.hardware.Sensor#TYPE_LIGHT Sensor.TYPE_LIGHT}:</h4> |
| * <ul> |
| * <li>values[0]: Ambient light level in SI lux units </li> |
| * </ul> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_PRESSURE Sensor.TYPE_PRESSURE}:</h4> |
| * <ul> |
| * <li>values[0]: Atmospheric pressure in hPa (millibar) </li> |
| * </ul> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_PROXIMITY Sensor.TYPE_PROXIMITY}: |
| * </h4> |
| * |
| * <ul> |
| * <li>values[0]: Proximity sensor distance measured in centimeters </li> |
| * </ul> |
| * |
| * <p> |
| * <b>Note:</b> Some proximity sensors only support a binary <i>near</i> or |
| * <i>far</i> measurement. In this case, the sensor should report its |
| * {@link android.hardware.Sensor#getMaximumRange() maximum range} value in |
| * the <i>far</i> state and a lesser value in the <i>near</i> state. |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_GRAVITY Sensor.TYPE_GRAVITY}:</h4> |
| * <p>A three dimensional vector indicating the direction and magnitude of gravity. Units |
| * are m/s^2. The coordinate system is the same as is used by the acceleration sensor.</p> |
| * <p><b>Note:</b> When the device is at rest, the output of the gravity sensor should be |
| * identical to that of the accelerometer.</p> |
| * |
| * <h4> |
| * {@link android.hardware.Sensor#TYPE_LINEAR_ACCELERATION Sensor.TYPE_LINEAR_ACCELERATION}: |
| * </h4> A three dimensional vector indicating acceleration along each device axis, not |
| * including gravity. All values have units of m/s^2. The coordinate system is the same as is |
| * used by the acceleration sensor. |
| * <p>The output of the accelerometer, gravity and linear-acceleration sensors must obey the |
| * following relation:</p> |
| * <p><ul>acceleration = gravity + linear-acceleration</ul></p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_ROTATION_VECTOR Sensor.TYPE_ROTATION_VECTOR}:</h4> |
| * <p>The rotation vector represents the orientation of the device as a combination of an |
| * <i>angle</i> and an <i>axis</i>, in which the device has rotated through an angle θ |
| * around an axis <x, y, z>.</p> |
| * <p>The three elements of the rotation vector are |
| * <x*sin(θ/2), y*sin(θ/2), z*sin(θ/2)>, such that the magnitude of the rotation |
| * vector is equal to sin(θ/2), and the direction of the rotation vector is equal to the |
| * direction of the axis of rotation.</p> |
| * </p>The three elements of the rotation vector are equal to |
| * the last three components of a <b>unit</b> quaternion |
| * <cos(θ/2), x*sin(θ/2), y*sin(θ/2), z*sin(θ/2)>.</p> |
| * <p>Elements of the rotation vector are unitless. |
| * The x,y, and z axis are defined in the same way as the acceleration |
| * sensor.</p> |
| * The reference coordinate system is defined as a direct orthonormal basis, |
| * where: |
| * </p> |
| * |
| * <ul> |
| * <li>X is defined as the vector product <b>Y.Z</b> (It is tangential to |
| * the ground at the device's current location and roughly points East).</li> |
| * <li>Y is tangential to the ground at the device's current location and |
| * points towards magnetic north.</li> |
| * <li>Z points towards the sky and is perpendicular to the ground.</li> |
| * </ul> |
| * |
| * <p> |
| * <center><img src="../../../images/axis_globe.png" |
| * alt="World coordinate-system diagram." border="0" /></center> |
| * </p> |
| * |
| * <ul> |
| * <li> values[0]: x*sin(θ/2) </li> |
| * <li> values[1]: y*sin(θ/2) </li> |
| * <li> values[2]: z*sin(θ/2) </li> |
| * <li> values[3]: cos(θ/2) </li> |
| * <li> values[4]: estimated heading Accuracy (in radians) (-1 if unavailable)</li> |
| * </ul> |
| * <p> values[3], originally optional, will always be present from SDK Level 18 onwards. |
| * values[4] is a new value that has been added in SDK Level 18. |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_ORIENTATION |
| * Sensor.TYPE_ORIENTATION}:</h4> All values are angles in degrees. |
| * |
| * <ul> |
| * <li> values[0]: Azimuth, angle between the magnetic north direction and the |
| * y-axis, around the z-axis (0 to 359). 0=North, 90=East, 180=South, |
| * 270=West |
| * </p> |
| * |
| * <p> |
| * values[1]: Pitch, rotation around x-axis (-180 to 180), with positive |
| * values when the z-axis moves <b>toward</b> the y-axis. |
| * </p> |
| * |
| * <p> |
| * values[2]: Roll, rotation around the y-axis (-90 to 90) |
| * increasing as the device moves clockwise. |
| * </p> |
| * </ul> |
| * |
| * <p> |
| * <b>Note:</b> This definition is different from <b>yaw, pitch and roll</b> |
| * used in aviation where the X axis is along the long side of the plane |
| * (tail to nose). |
| * </p> |
| * |
| * <p> |
| * <b>Note:</b> This sensor type exists for legacy reasons, please use |
| * {@link android.hardware.Sensor#TYPE_ROTATION_VECTOR |
| * rotation vector sensor type} and |
| * {@link android.hardware.SensorManager#getRotationMatrix |
| * getRotationMatrix()} in conjunction with |
| * {@link android.hardware.SensorManager#remapCoordinateSystem |
| * remapCoordinateSystem()} and |
| * {@link android.hardware.SensorManager#getOrientation getOrientation()} to |
| * compute these values instead. |
| * </p> |
| * |
| * <p> |
| * <b>Important note:</b> For historical reasons the roll angle is positive |
| * in the clockwise direction (mathematically speaking, it should be |
| * positive in the counter-clockwise direction). |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_RELATIVE_HUMIDITY |
| * Sensor.TYPE_RELATIVE_HUMIDITY}:</h4> |
| * <ul> |
| * <li> values[0]: Relative ambient air humidity in percent </li> |
| * </ul> |
| * <p> |
| * When relative ambient air humidity and ambient temperature are |
| * measured, the dew point and absolute humidity can be calculated. |
| * </p> |
| * <u>Dew Point</u> |
| * <p> |
| * The dew point is the temperature to which a given parcel of air must be |
| * cooled, at constant barometric pressure, for water vapor to condense |
| * into water. |
| * </p> |
| * <center><pre> |
| * ln(RH/100%) + m·t/(T<sub>n</sub>+t) |
| * t<sub>d</sub>(t,RH) = T<sub>n</sub> · ------------------------------ |
| * m - [ln(RH/100%) + m·t/(T<sub>n</sub>+t)] |
| * </pre></center> |
| * <dl> |
| * <dt>t<sub>d</sub></dt> <dd>dew point temperature in °C</dd> |
| * <dt>t</dt> <dd>actual temperature in °C</dd> |
| * <dt>RH</dt> <dd>actual relative humidity in %</dd> |
| * <dt>m</dt> <dd>17.62</dd> |
| * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd> |
| * </dl> |
| * <p>for example:</p> |
| * <pre class="prettyprint"> |
| * h = Math.log(rh / 100.0) + (17.62 * t) / (243.12 + t); |
| * td = 243.12 * h / (17.62 - h); |
| * </pre> |
| * <u>Absolute Humidity</u> |
| * <p> |
| * The absolute humidity is the mass of water vapor in a particular volume |
| * of dry air. The unit is g/m<sup>3</sup>. |
| * </p> |
| * <center><pre> |
| * RH/100%·A·exp(m·t/(T<sub>n</sub>+t)) |
| * d<sub>v</sub>(t,RH) = 216.7 · ------------------------- |
| * 273.15 + t |
| * </pre></center> |
| * <dl> |
| * <dt>d<sub>v</sub></dt> <dd>absolute humidity in g/m<sup>3</sup></dd> |
| * <dt>t</dt> <dd>actual temperature in °C</dd> |
| * <dt>RH</dt> <dd>actual relative humidity in %</dd> |
| * <dt>m</dt> <dd>17.62</dd> |
| * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd> |
| * <dt>A</dt> <dd>6.112 hPa</dd> |
| * </dl> |
| * <p>for example:</p> |
| * <pre class="prettyprint"> |
| * dv = 216.7 * |
| * (rh / 100.0 * 6.112 * Math.exp(17.62 * t / (243.12 + t)) / (273.15 + t)); |
| * </pre> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_AMBIENT_TEMPERATURE Sensor.TYPE_AMBIENT_TEMPERATURE}: |
| * </h4> |
| * |
| * <ul> |
| * <li> values[0]: ambient (room) temperature in degree Celsius.</li> |
| * </ul> |
| * |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_MAGNETIC_FIELD_UNCALIBRATED |
| * Sensor.TYPE_MAGNETIC_FIELD_UNCALIBRATED}:</h4> |
| * Similar to {@link android.hardware.Sensor#TYPE_MAGNETIC_FIELD}, |
| * but the hard iron calibration is reported separately instead of being included |
| * in the measurement. Factory calibration and temperature compensation will still |
| * be applied to the "uncalibrated" measurement. Assumptions that the magnetic field |
| * is due to the Earth's poles is avoided. |
| * <p> |
| * The values array is shown below: |
| * <ul> |
| * <li> values[0] = x_uncalib </li> |
| * <li> values[1] = y_uncalib </li> |
| * <li> values[2] = z_uncalib </li> |
| * <li> values[3] = x_bias </li> |
| * <li> values[4] = y_bias </li> |
| * <li> values[5] = z_bias </li> |
| * </ul> |
| * </p> |
| * <p> |
| * x_uncalib, y_uncalib, z_uncalib are the measured magnetic field in X, Y, Z axes. |
| * Soft iron and temperature calibrations are applied. But the hard iron |
| * calibration is not applied. The values are in micro-Tesla (uT). |
| * </p> |
| * <p> |
| * x_bias, y_bias, z_bias give the iron bias estimated in X, Y, Z axes. |
| * Each field is a component of the estimated hard iron calibration. |
| * The values are in micro-Tesla (uT). |
| * </p> |
| * <p> Hard iron - These distortions arise due to the magnetized iron, steel or permanent |
| * magnets on the device. |
| * Soft iron - These distortions arise due to the interaction with the earth's magnetic |
| * field. |
| * </p> |
| * <h4> {@link android.hardware.Sensor#TYPE_GAME_ROTATION_VECTOR |
| * Sensor.TYPE_GAME_ROTATION_VECTOR}:</h4> |
| * Identical to {@link android.hardware.Sensor#TYPE_ROTATION_VECTOR} except that it |
| * doesn't use the geomagnetic field. Therefore the Y axis doesn't |
| * point north, but instead to some other reference, that reference is |
| * allowed to drift by the same order of magnitude as the gyroscope |
| * drift around the Z axis. |
| * <p> |
| * In the ideal case, a phone rotated and returning to the same real-world |
| * orientation will report the same game rotation vector |
| * (without using the earth's geomagnetic field). However, the orientation |
| * may drift somewhat over time. See {@link android.hardware.Sensor#TYPE_ROTATION_VECTOR} |
| * for a detailed description of the values. This sensor will not have |
| * the estimated heading accuracy value. |
| * </p> |
| * |
| * <h4> {@link android.hardware.Sensor#TYPE_GYROSCOPE_UNCALIBRATED |
| * Sensor.TYPE_GYROSCOPE_UNCALIBRATED}:</h4> |
| * All values are in radians/second and measure the rate of rotation |
| * around the X, Y and Z axis. An estimation of the drift on each axis is |
| * reported as well. |
| * <p> |
| * No gyro-drift compensation is performed. Factory calibration and temperature |
| * compensation is still applied to the rate of rotation (angular speeds). |
| * </p> |
| * <p> |
| * The coordinate system is the same as is used for the |
| * {@link android.hardware.Sensor#TYPE_ACCELEROMETER} |
| * Rotation is positive in the counter-clockwise direction (right-hand rule). |
| * That is, an observer looking from some positive location on the x, y or z axis |
| * at a device positioned on the origin would report positive rotation if the device |
| * appeared to be rotating counter clockwise. |
| * The range would at least be 17.45 rad/s (ie: ~1000 deg/s). |
| * <ul> |
| * <li> values[0] : angular speed (w/o drift compensation) around the X axis in rad/s </li> |
| * <li> values[1] : angular speed (w/o drift compensation) around the Y axis in rad/s </li> |
| * <li> values[2] : angular speed (w/o drift compensation) around the Z axis in rad/s </li> |
| * <li> values[3] : estimated drift around X axis in rad/s </li> |
| * <li> values[4] : estimated drift around Y axis in rad/s </li> |
| * <li> values[5] : estimated drift around Z axis in rad/s </li> |
| * </ul> |
| * </p> |
| * <p><b>Pro Tip:</b> Always use the length of the values array while performing operations |
| * on it. In earlier versions, this used to be always 3 which has changed now. </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_POSE_6DOF |
| * Sensor.TYPE_POSE_6DOF}:</h4> |
| * |
| * A TYPE_POSE_6DOF event consists of a rotation expressed as a quaternion and a translation |
| * expressed in SI units. The event also contains a delta rotation and translation that show |
| * how the device?s pose has changed since the previous sequence numbered pose. |
| * The event uses the cannonical Android Sensor axes. |
| * |
| * |
| * <ul> |
| * <li> values[0]: x*sin(θ/2) </li> |
| * <li> values[1]: y*sin(θ/2) </li> |
| * <li> values[2]: z*sin(θ/2) </li> |
| * <li> values[3]: cos(θ/2) </li> |
| * |
| * |
| * <li> values[4]: Translation along x axis from an arbitrary origin. </li> |
| * <li> values[5]: Translation along y axis from an arbitrary origin. </li> |
| * <li> values[6]: Translation along z axis from an arbitrary origin. </li> |
| * |
| * <li> values[7]: Delta quaternion rotation x*sin(θ/2) </li> |
| * <li> values[8]: Delta quaternion rotation y*sin(θ/2) </li> |
| * <li> values[9]: Delta quaternion rotation z*sin(θ/2) </li> |
| * <li> values[10]: Delta quaternion rotation cos(θ/2) </li> |
| * |
| * <li> values[11]: Delta translation along x axis. </li> |
| * <li> values[12]: Delta translation along y axis. </li> |
| * <li> values[13]: Delta translation along z axis. </li> |
| * |
| * <li> values[14]: Sequence number </li> |
| * |
| * </ul> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_STATIONARY_DETECT |
| * Sensor.TYPE_STATIONARY_DETECT}:</h4> |
| * |
| * A TYPE_STATIONARY_DETECT event is produced if the device has been |
| * stationary for at least 5 seconds with a maximal latency of 5 |
| * additional seconds. ie: it may take up anywhere from 5 to 10 seconds |
| * afte the device has been at rest to trigger this event. |
| * |
| * The only allowed value is 1.0. |
| * |
| * <ul> |
| * <li> values[0]: 1.0 </li> |
| * </ul> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_MOTION_DETECT |
| * Sensor.TYPE_MOTION_DETECT}:</h4> |
| * |
| * A TYPE_MOTION_DETECT event is produced if the device has been in |
| * motion for at least 5 seconds with a maximal latency of 5 |
| * additional seconds. ie: it may take up anywhere from 5 to 10 seconds |
| * afte the device has been at rest to trigger this event. |
| * |
| * The only allowed value is 1.0. |
| * |
| * <ul> |
| * <li> values[0]: 1.0 </li> |
| * </ul> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_HEART_BEAT |
| * Sensor.TYPE_HEART_BEAT}:</h4> |
| * |
| * A sensor of this type returns an event everytime a hear beat peak is |
| * detected. |
| * |
| * Peak here ideally corresponds to the positive peak in the QRS complex of |
| * an ECG signal. |
| * |
| * <ul> |
| * <li> values[0]: confidence</li> |
| * </ul> |
| * |
| * <p> |
| * A confidence value of 0.0 indicates complete uncertainty - that a peak |
| * is as likely to be at the indicated timestamp as anywhere else. |
| * A confidence value of 1.0 indicates complete certainly - that a peak is |
| * completely unlikely to be anywhere else on the QRS complex. |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_LOW_LATENCY_OFFBODY_DETECT |
| * Sensor.TYPE_LOW_LATENCY_OFFBODY_DETECT}:</h4> |
| * |
| * <p> |
| * A sensor of this type returns an event every time the device transitions |
| * from off-body to on-body and from on-body to off-body (e.g. a wearable |
| * device being removed from the wrist would trigger an event indicating an |
| * off-body transition). The event returned will contain a single value to |
| * indicate off-body state: |
| * </p> |
| * |
| * <ul> |
| * <li> values[0]: off-body state</li> |
| * </ul> |
| * |
| * <p> |
| * Valid values for off-body state: |
| * <ul> |
| * <li> 1.0 (device is on-body)</li> |
| * <li> 0.0 (device is off-body)</li> |
| * </ul> |
| * </p> |
| * |
| * <p> |
| * When a sensor of this type is activated, it must deliver the initial |
| * on-body or off-body event representing the current device state within |
| * 5 seconds of activating the sensor. |
| * </p> |
| * |
| * <p> |
| * This sensor must be able to detect and report an on-body to off-body |
| * transition within 1 second of the device being removed from the body, |
| * and must be able to detect and report an off-body to on-body transition |
| * within 5 seconds of the device being put back onto the body. |
| * </p> |
| * |
| * <h4>{@link android.hardware.Sensor#TYPE_ACCELEROMETER_UNCALIBRATED |
| * Sensor.TYPE_ACCELEROMETER_UNCALIBRATED}:</h4> All values are in SI |
| * units (m/s^2) |
| * |
| * Similar to {@link android.hardware.Sensor#TYPE_ACCELEROMETER}, |
| * Factory calibration and temperature compensation will still be applied |
| * to the "uncalibrated" measurement. |
| * |
| * <p> |
| * The values array is shown below: |
| * <ul> |
| * <li> values[0] = x_uncalib without bias compensation </li> |
| * <li> values[1] = y_uncalib without bias compensation </li> |
| * <li> values[2] = z_uncalib without bias compensation </li> |
| * <li> values[3] = estimated x_bias </li> |
| * <li> values[4] = estimated y_bias </li> |
| * <li> values[5] = estimated z_bias </li> |
| * </ul> |
| * </p> |
| * <p> |
| * x_uncalib, y_uncalib, z_uncalib are the measured acceleration in X, Y, Z |
| * axes similar to the {@link android.hardware.Sensor#TYPE_ACCELEROMETER}, |
| * without any bias correction (factory bias compensation and any |
| * temperature compensation is allowed). |
| * x_bias, y_bias, z_bias are the estimated biases. |
| * </p> |
| * |
| * @see GeomagneticField |
| */ |
| public final float[] values; |
| |
| /** |
| * The sensor that generated this event. See |
| * {@link android.hardware.SensorManager SensorManager} for details. |
| */ |
| public Sensor sensor; |
| |
| /** |
| * The accuracy of this event. See {@link android.hardware.SensorManager |
| * SensorManager} for details. |
| */ |
| public int accuracy; |
| |
| /** |
| * The time in nanosecond at which the event happened |
| */ |
| public long timestamp; |
| |
| @UnsupportedAppUsage |
| SensorEvent(int valueSize) { |
| values = new float[valueSize]; |
| } |
| } |
