19066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project/* 29066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Copyright (C) 2008 The Android Open Source Project 39066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 49066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 59066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * you may not use this file except in compliance with the License. 69066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * You may obtain a copy of the License at 79066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 89066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 99066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 109066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 119066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 129066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 139066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * See the License for the specific language governing permissions and 149066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * limitations under the License. 159066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 169066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 179066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpackage android.hardware; 189066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 199066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project/** 2074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 2174cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * This class represents a {@link android.hardware.Sensor Sensor} event and 2274cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * holds informations such as the sensor's type, the time-stamp, accuracy and of 2374cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * course the sensor's {@link SensorEvent#values data}. 2474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 259066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 2674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 2774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <u>Definition of the coordinate system used by the SensorEvent API.</u> 2874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 2974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * 3074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 310f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * The coordinate-system is defined relative to the screen of the phone in its 3274cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * default orientation. The axes are not swapped when the device's screen 3374cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * orientation changes. 3474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 3574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * 3674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 370f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * The X axis is horizontal and points to the right, the Y axis is vertical and 380f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * points up and the Z axis points towards the outside of the front face of the 390f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * screen. In this system, coordinates behind the screen have negative Z values. 400f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 410f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 420f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 430f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <center><img src="../../../images/axis_device.png" 440f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * alt="Sensors coordinate-system diagram." border="0" /></center> 4574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 4674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * 4774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 489066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * <b>Note:</b> This coordinate system is different from the one used in the 4974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * Android 2D APIs where the origin is in the top-left corner. 5074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 519066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 520f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * @see SensorManager 530f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * @see SensorEvent 540f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * @see Sensor 559066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * 569066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 579066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 589066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Projectpublic class SensorEvent { 599066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 6074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 610f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * The length and contents of the {@link #values values} array depends on 620f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * which {@link android.hardware.Sensor sensor} type is being monitored (see 630f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * also {@link SensorEvent} for a definition of the coordinate system used). 6474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </p> 6574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * 660f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_ACCELEROMETER 670f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * Sensor.TYPE_ACCELEROMETER}:</h4> All values are in SI units (m/s^2) 680f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 6974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <ul> 7074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 710f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[0]: Acceleration minus Gx on the x-axis 720f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 7374cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 740f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[1]: Acceleration minus Gy on the y-axis 750f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 7674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 770f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[2]: Acceleration minus Gz on the z-axis 780f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 7974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </ul> 800f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 8174cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 820f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * A sensor of this type measures the acceleration applied to the device 830f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * (<b>Ad</b>). Conceptually, it does so by measuring forces applied to the 840f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * sensor itself (<b>Fs</b>) using the relation: 850f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 860f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 87612ff27425cf2976396d992f32b58ab900c7d708Brad Fitzpatrick * <b><center>Ad = - ∑Fs / mass</center></b> 880f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 8974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 900f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * In particular, the force of gravity is always influencing the measured 910f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * acceleration: 920f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 930f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 94612ff27425cf2976396d992f32b58ab900c7d708Brad Fitzpatrick * <b><center>Ad = -g - ∑F / mass</center></b> 950f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 9674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 970f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * For this reason, when the device is sitting on a table (and obviously not 980f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * accelerating), the accelerometer reads a magnitude of <b>g</b> = 9.81 990f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * m/s^2 1000f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 1010f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 10274cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 1030f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * Similarly, when the device is in free-fall and therefore dangerously 1040f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * accelerating towards to ground at 9.81 m/s^2, its accelerometer reads a 1050f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * magnitude of 0 m/s^2. 1060f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 1070f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 10874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 1090f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * It should be apparent that in order to measure the real acceleration of 1100f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * the device, the contribution of the force of gravity must be eliminated. 1110f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * This can be achieved by applying a <i>high-pass</i> filter. Conversely, a 1120f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <i>low-pass</i> filter can be used to isolate the force of gravity. 1130f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 114fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 115fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <pre class="prettyprint"> 116fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 117fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * public void onSensorChanged(SensorEvent event) 118fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * { 119fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * // alpha is calculated as t / (t + dT) 120fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * // with t, the low-pass filter's time-constant 121fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * // and dT, the event delivery rate 122fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 123fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * final float alpha = 0.8; 124fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 125d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * gravity[0] = alpha * gravity[0] + (1 - alpha) * event.values[0]; 126d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * gravity[1] = alpha * gravity[1] + (1 - alpha) * event.values[1]; 127d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * gravity[2] = alpha * gravity[2] + (1 - alpha) * event.values[2]; 128fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 129d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * linear_acceleration[0] = event.values[0] - gravity[0]; 130d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * linear_acceleration[1] = event.values[1] - gravity[1]; 131d11ee90b6ed54421f0016ffb7de77e5c812bc17fScott Main * linear_acceleration[2] = event.values[2] - gravity[2]; 132fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * } 133fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </pre> 134fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * 13574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 13674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <u>Examples</u>: 13774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <ul> 13874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <li>When the device lies flat on a table and is pushed on its left side 13974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * toward the right, the x acceleration value is positive.</li> 1400f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 14174cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <li>When the device lies flat on a table, the acceleration value is 14274cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * +9.81, which correspond to the acceleration of the device (0 m/s^2) minus 14374cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * the force of gravity (-9.81 m/s^2).</li> 1440f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 14574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <li>When the device lies flat on a table and is pushed toward the sky 14674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * with an acceleration of A m/s^2, the acceleration value is equal to 14774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * A+9.81 which correspond to the acceleration of the device (+A m/s^2) 14874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * minus the force of gravity (-9.81 m/s^2).</li> 14974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </ul> 1500f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 1510f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 1520f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_MAGNETIC_FIELD 1530f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * Sensor.TYPE_MAGNETIC_FIELD}:</h4> 15474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * All values are in micro-Tesla (uT) and measure the ambient magnetic field 15574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * in the X, Y and Z axis. 1560f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 157ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_GYROSCOPE Sensor.TYPE_GYROSCOPE}: 158ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * </h4> All values are in radians/second and measure the rate of rotation 159ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * around the device's local X, Y and Z axis. The coordinate system is the 160ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * same as is used for the acceleration sensor. Rotation is positive in the 161ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * counter-clockwise direction. That is, an observer looking from some 162ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * positive location on the x, y or z axis at a device positioned on the 163ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * origin would report positive rotation if the device appeared to be 164ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * rotating counter clockwise. Note that this is the standard mathematical 165ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * definition of positive rotation and does not agree with the definition of 166ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * roll given earlier. 167fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <ul> 168fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <p> 169fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * values[0]: Angular speed around the x-axis 170fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </p> 171fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <p> 172fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * values[1]: Angular speed around the y-axis 173fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </p> 174fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <p> 175fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * values[2]: Angular speed around the z-axis 176fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </p> 177fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </ul> 178fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <p> 179ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * Typically the output of the gyroscope is integrated over time to 180ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * calculate a rotation describing the change of angles over the timestep, 181ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * for example: 182fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </p> 183ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * 184fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * <pre class="prettyprint"> 185fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * private static final float NS2S = 1.0f / 1000000000.0f; 186ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * private final float[] deltaRotationVector = new float[4](); 187fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * private float timestamp; 188ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * 189ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * public void onSensorChanged(SensorEvent event) { 190ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // This timestep's delta rotation to be multiplied by the current rotation 191ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // after computing it from the gyro sample data. 192fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * if (timestamp != 0) { 193fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * final float dT = (event.timestamp - timestamp) * NS2S; 194ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // Axis of the rotation sample, not normalized yet. 195ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float axisX = event.values[0]; 196ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float axisY = event.values[1]; 197ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float axisZ = event.values[2]; 198ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * 199ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // Calculate the angular speed of the sample 200ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float omegaMagnitude = sqrt(axisX*axisX + axisY*axisY + axisZ*axisZ); 201ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * 202ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // Normalize the rotation vector if it's big enough to get the axis 203ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * if (omegaMagnitude > EPSILON) { 204ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * axisX /= omegaMagnitude; 205ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * axisY /= omegaMagnitude; 206ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * axisZ /= omegaMagnitude; 207ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * } 208ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * 209ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // Integrate around this axis with the angular speed by the timestep 210ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // in order to get a delta rotation from this sample over the timestep 211ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // We will convert this axis-angle representation of the delta rotation 212ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // into a quaternion before turning it into the rotation matrix. 213ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float thetaOverTwo = omegaMagnitude * dT / 2.0f; 214ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float sinThetaOverTwo = sin(thetaOverTwo); 215ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float cosThetaOverTwo = cos(thetaOverTwo); 216ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * deltaRotationVector[0] = sinThetaOverTwo * axisX; 217ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * deltaRotationVector[1] = sinThetaOverTwo * axisY; 218ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * deltaRotationVector[2] = sinThetaOverTwo * axisZ; 219ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * deltaRotationVector[3] = cosThetaOverTwo; 220fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * } 221fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * timestamp = event.timestamp; 222ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * float[] deltaRotationMatrix = new float[9]; 223ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * SensorManager.getRotationMatrixFromVector(deltaRotationMatrix, deltaRotationVector); 224ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // User code should concatenate the delta rotation we computed with the current rotation 225ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // in order to get the updated rotation. 226ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * // rotationCurrent = rotationCurrent * deltaRotationMatrix; 227fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * } 228fa33565714e4192dbab446ee1fbccb87dd414bedMathias Agopian * </pre> 229ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * <p> 230ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * In practice, the gyroscope noise and offset will introduce some errors 231ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * which need to be compensated for. This is usually done using the 232ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * information from other sensors, but is beyond the scope of this document. 233ad7f33a29c6ce41f2b662d1de9af7e9cf92f4dc9Mathias Agopian * </p> 2340f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_LIGHT Sensor.TYPE_LIGHT}:</h4> 23574cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <ul> 23674cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 23774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * values[0]: Ambient light level in SI lux units 23874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </ul> 2390f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 2401260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_PRESSURE Sensor.TYPE_PRESSURE}:</h4> 2411260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * <ul> 2421260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * <p> 2431260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * values[0]: Atmospheric pressure in hPa (millibar) 2441260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * </ul> 2451260a89b54436fdd6d80e7c98b7db3c55f85104cMathias Agopian * 2460f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_PROXIMITY Sensor.TYPE_PROXIMITY}: 2470f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </h4> 2480f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 24974cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <ul> 25074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 25174cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * values[0]: Proximity sensor distance measured in centimeters 25274cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * </ul> 2530f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 25474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * <p> 2550f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <b>Note:</b> Some proximity sensors only support a binary <i>near</i> or 2560f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <i>far</i> measurement. In this case, the sensor should report its 2570f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * {@link android.hardware.Sensor#getMaximumRange() maximum range} value in 2580f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * the <i>far</i> state and a lesser value in the <i>near</i> state. 2590f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 2600f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 2617a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * <h4>{@link android.hardware.Sensor#TYPE_GRAVITY Sensor.TYPE_GRAVITY}:</h4> 2627badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p>A three dimensional vector indicating the direction and magnitude of gravity. Units 2637badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * are m/s^2. The coordinate system is the same as is used by the acceleration sensor.</p> 2647badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p><b>Note:</b> When the device is at rest, the output of the gravity sensor should be identical 2657badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * to that of the accelerometer.</p> 2667a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * 2677a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * <h4>{@link android.hardware.Sensor#TYPE_LINEAR_ACCELERATION Sensor.TYPE_LINEAR_ACCELERATION}:</h4> 2687a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * A three dimensional vector indicating acceleration along each device axis, not including 2697a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * gravity. All values have units of m/s^2. The coordinate system is the same as is used by the 2707badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * acceleration sensor. 2717badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p>The output of the accelerometer, gravity and linear-acceleration sensors must obey the 2727badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * following relation:</p> 2737badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p><ul>acceleration = gravity + linear-acceleration</ul></p> 2747a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * 2757a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * <h4>{@link android.hardware.Sensor#TYPE_ROTATION_VECTOR Sensor.TYPE_ROTATION_VECTOR}:</h4> 2767badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p>The rotation vector represents the orientation of the device as a combination of an <i>angle</i> 2777badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * and an <i>axis</i>, in which the device has rotated through an angle θ around an axis 2787badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <x, y, z>.</p> 2797badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p>The three elements of the rotation vector are 2807badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <x*sin(θ/2), y*sin(θ/2), z*sin(θ/2)>, such that the magnitude of the rotation 2817badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * vector is equal to sin(θ/2), and the direction of the rotation vector is equal to the 2827badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * direction of the axis of rotation.</p> 2837badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </p>The three elements of the rotation vector are equal to 2847badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * the last three components of a <b>unit</b> quaternion 2857badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <cos(θ/2), x*sin(θ/2), y*sin(θ/2), z*sin(θ/2)>.</p> 2867badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p>Elements of the rotation vector are unitless. 2877badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * The x,y, and z axis are defined in the same way as the acceleration 2887badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * sensor.</p> 289d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * The reference coordinate system is defined as a direct orthonormal basis, 290d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * where: 291d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * </p> 292d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * 293d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <ul> 294d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <li>X is defined as the vector product <b>Y.Z</b> (It is tangential to 295d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * the ground at the device's current location and roughly points East).</li> 296d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <li>Y is tangential to the ground at the device's current location and 29752bfc243684b2f340da326aaa38e9021e4e3b2e6Scott Main * points towards magnetic north.</li> 298d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <li>Z points towards the sky and is perpendicular to the ground.</li> 299d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * </ul> 300d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * 301d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <p> 302d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * <center><img src="../../../images/axis_globe.png" 303d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * alt="World coordinate-system diagram." border="0" /></center> 304d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * </p> 305d84d2b7b1ee5c37da878534f4d493d8d00a3f65fMathias Agopian * 3067badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <ul> 3077badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p> 3087badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * values[0]: x*sin(θ/2) 3097badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </p> 3107badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p> 3117badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * values[1]: y*sin(θ/2) 3127badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </p> 3137badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p> 3147badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * values[2]: z*sin(θ/2) 3157badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </p> 3167badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * <p> 3177badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * values[3]: cos(θ/2) <i>(optional: only if value.length = 4)</i> 3187badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </p> 3197badd2c402f9e8e9fd13f6915ad2e32301f9f305Mathias Agopian * </ul> 3207a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell * 3210f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_ORIENTATION 3220f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * Sensor.TYPE_ORIENTATION}:</h4> All values are angles in degrees. 3230f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3240f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <ul> 3250f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3260f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[0]: Azimuth, angle between the magnetic north direction and the 3270f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * y-axis, around the z-axis (0 to 359). 0=North, 90=East, 180=South, 3280f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 270=West 3290f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3300f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3310f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3320f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[1]: Pitch, rotation around x-axis (-180 to 180), with positive 3330f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values when the z-axis moves <b>toward</b> the y-axis. 3340f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3350f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3360f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3370f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * values[2]: Roll, rotation around y-axis (-90 to 90), with positive values 3380f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * when the x-axis moves <b>toward</b> the z-axis. 3390f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3400f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </ul> 3410f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3420f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3430f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <b>Note:</b> This definition is different from <b>yaw, pitch and roll</b> 3440f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * used in aviation where the X axis is along the long side of the plane 3450f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * (tail to nose). 3460f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3470f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3480f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3490f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <b>Note:</b> This sensor type exists for legacy reasons, please use 3500f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * {@link android.hardware.SensorManager#getRotationMatrix 3510f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * getRotationMatrix()} in conjunction with 3520f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * {@link android.hardware.SensorManager#remapCoordinateSystem 3530f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * remapCoordinateSystem()} and 3540f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * {@link android.hardware.SensorManager#getOrientation getOrientation()} to 3550f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * compute these values instead. 3560f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3570f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 3580f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <p> 3590f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * <b>Important note:</b> For historical reasons the roll angle is positive 3600f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * in the clockwise direction (mathematically speaking, it should be 3610f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * positive in the counter-clockwise direction). 3620f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * </p> 3635819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * 3645819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <h4>{@link android.hardware.Sensor#TYPE_RELATIVE_HUMIDITY 3655819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * Sensor.TYPE_RELATIVE_HUMIDITY}:</h4> 3665819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <ul> 3675819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p> 3685819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * values[0]: Relative ambient air humidity in percent 3695819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </p> 3705819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </ul> 3715819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p> 3725819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * When relative ambient air humidity and ambient temperature are 3735819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * measured, the dew point and absolute humidity can be calculated. 3745819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </p> 3755819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <u>Dew Point</u> 3765819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p> 3775819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * The dew point is the temperature to which a given parcel of air must be 3785819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * cooled, at constant barometric pressure, for water vapor to condense 3795819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * into water. 3805819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </p> 3815819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <center><pre> 3825819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * ln(RH/100%) + m·t/(T<sub>n</sub>+t) 3835819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * t<sub>d</sub>(t,RH) = T<sub>n</sub> · ------------------------------ 3845819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * m - [ln(RH/100%) + m·t/(T<sub>n</sub>+t)] 3855819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </pre></center> 3865819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dl> 3875819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>t<sub>d</sub></dt> <dd>dew point temperature in °C</dd> 3885819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>t</dt> <dd>actual temperature in °C</dd> 3895819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>RH</dt> <dd>actual relative humidity in %</dd> 3905819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>m</dt> <dd>17.62</dd> 3915819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd> 3925819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </dl> 3935819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p>for example:</p> 3945819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <pre class="prettyprint"> 3955819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * h = Math.log(rh / 100.0) + (17.62 * t) / (243.12 + t); 3965819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * td = 243.12 * h / (17.62 - h); 3975819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </pre> 3985819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <u>Absolute Humidity</u> 3995819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p> 4005819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * The absolute humidity is the mass of water vapor in a particular volume 4015819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * of dry air. The unit is g/m<sup>3</sup>. 4025819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </p> 4035819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <center><pre> 4045819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * RH/100%·A·exp(m·t/(T<sub>n</sub>+t)) 4055819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * d<sub>v</sub>(t,RH) = 216.7 · ------------------------- 4065819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * 273.15 + t 4075819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </pre></center> 4085819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dl> 4095819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>d<sub>v</sub></dt> <dd>absolute humidity in g/m<sup>3</sup></dd> 4105819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>t</dt> <dd>actual temperature in °C</dd> 4115819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>RH</dt> <dd>actual relative humidity in %</dd> 4125819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>m</dt> <dd>17.62</dd> 4135819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>T<sub>n</sub></dt> <dd>243.12 °C</dd> 4145819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <dt>A</dt> <dd>6.112 hPa</dd> 4155819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </dl> 4165819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <p>for example:</p> 4175819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * <pre class="prettyprint"> 4185819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * dv = 216.7 * 4195819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * (rh / 100.0 * 6.112 * Math.exp(17.62 * t / (243.12 + t)) / (273.15 + t)); 4205819051eee071d622e5cb1f32c74112b1c7b1072Urs Fleisch * </pre> 4210f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * 422462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * <h4>{@link android.hardware.Sensor#TYPE_AMBIENT_TEMPERATURE Sensor.TYPE_AMBIENT_TEMPERATURE}: 423462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * </h4> 424462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * 425462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * <ul> 426462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * <p> 427462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * values[0]: ambient (room) temperature in degree Celsius. 428462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * </ul> 429462db220a2986f7d9fc3d7e3e6af6615570eaa0bMathias Agopian * 4300f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * @see SensorEvent 4310f791a799dc81d93935fd2597297cf7ac2c0a044Mathias Agopian * @see GeomagneticField 4324115c518753052add46b017bb3044da6f6169a7bMike Lockwood */ 4337a0541d6b803da02b8724b1d140d6ccaaec23a36Kevin Powell 4349066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public final float[] values; 4359066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 4369066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 43774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * The sensor that generated this event. See 43874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * {@link android.hardware.SensorManager SensorManager} for details. 4399066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 44074cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian public Sensor sensor; 44174cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian 4429066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 44374cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * The accuracy of this event. See {@link android.hardware.SensorManager 44474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian * SensorManager} for details. 4459066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 4469066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public int accuracy; 44774cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian 44874cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian 4499066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project /** 4509066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project * The time in nanosecond at which the event happened 4519066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project */ 4529066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project public long timestamp; 4539066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project 45474cde2cee9e53006a710f4e80700cd560c2d0e4dMathias Agopian 4559066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project SensorEvent(int size) { 4569066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project values = new float[size]; 4579066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project } 4589066cfe9886ac131c34d59ed0e2d287b0e3c0087The Android Open Source Project} 459