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Search found 6 results on 1 pages for 'magnetometer'.

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  • Basic doubt about sensor usage

    - by Al
    Suppose I have a cellphone with accelerometer and magnetometer, and want to determine its absolute (wrt North/East/South/West) 3d position. Imagine the phone is laid vertically, with the screen facing me, the "up" vector pointing to the ceil. Whenever I tilt, the accelerometer allows me to get the "up" vector info change. The problem is that if I tilt the device and put it horizontally (screen now facing ceil, and "up" vector pointing to the opposite of where I am), then the up vector doesn't get updated any more if I rotate the phone horizontally on the table. This is something that clearly is detected by the magnetometer now. So, the question is, when to know where to use acc or mag for each case? Is there a generic way to achieve this?

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  • Finding the displacment of a robot [closed]

    - by Jordan Brown
    I'm building a quadruped (4 legs 3 DOF) for my major work in electronics at high school. I need to know the displacement of the robot and I can't use an encoding wheel. I've done my research and I found a system where I use an accelerometer, gyroscope and a magnetometer to determine the displacement but I'm not sure how to code it. I'm using Arduino and will use compatible sensors. I would like to be able to implement something similar to this video which demonstrates the principles evaluated in this paper. I don't need to map the data on a screen, just be able to read its displacement from its last recorded position. EG. (Read Position) --- (Do "stuff") --- (Read Position) --- (Calculate displacement caused by "stuff")

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  • XOLO X900–First mobile phone with Intel Power

    - by Rekha
    XOLO X900, XOLO’s offering the world’s first smart phone with the power of Intel inside® shaking hands with LAVA International Ltd., India’s fastest growing handset brands. The R&D Centre is in Shenzhan (China) and Bangalore (India). The smart phone has a fast web browsing with the 1.6 GHz Intel processor and smooth multi-tasking process using Intel patented Hyper Threading technology.It has an optimum battery usage, 4.03” hi-resolution of 1024X600 pixels LCD screen to ensure crisp text and vibrant images, HDMI Output port for TV, full HD 1080p playback and dual speakers. It has a camera of 8MP HD camera with certain DSLR like features allowing to click upto 10 photos in less than a second. 3D and HD gaming is immensely realistic with 400 MHz Graphics Processing Unit. The Operating System used here is Android 2.3 (Gingerbread) and upgradable to Android 4.0. It has the GPS facility and rear and front cameras with 8MP and 1.3MP respectively.  They have enabled Accelerometer, Gyroscope, Magnetometer, Ambient light sensor and Proximity sensor in this smart phone. Intel’s smartphone venture is beginning in India first. It is said to be available for sale in Indian from April 23, 2011 onwards. The price is at a best-buy price of INR 22,000 approximately. The smartphone will be available at the Indian retail chain Croma. The phone will available in other retail stores and online stores from early May. The company is launching the smartphone in India first and a more powerful handset in China later this year. According to their success in India and China, Intel is planning to come into Europe and US market. Till then, Intel smartphones are only for Indian buyers. You can more technical information from the XOLO’s site.

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  • iphone compass tilt compensation

    - by m01d
    hi, has anybody already programmed a iphone compass heading tilt compensation? i have got some approaches, but some help or a better solution would be cool! FIRST i define a vector Ev, calculated out of the cross product of Gv and Hv. Gv is a gravity vector i build out of the accelerometer values and Hv is an heading vector built out the magnetometer values. Ev stands perpendicular on Gv and Hv, so it is heading to horizonatl East. SECOND i define a vector Rv, calculated out of the cross product Bv and Gv. Bv is my looking vector and it is defined as [0,0,-1]. Rv is perpendicular to Gv and Bv and shows always to the right. THIRD the angle between these two vectors, Ev and Rv, should be my corrected heading. to calculate the angle i build the dot product and thereof the arcos. phi = arcos ( Ev * Rv / |Ev| * |Rv| ) Theoretically it should work, but maybe i have to normalize the vectors?! Has anybody got a solution for this? Thanks, m01d

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  • How to use onSensorChanged sensor data in combination with OpenGL

    - by Sponge
    I have written a TestSuite to find out how to calculate the rotation angles from the data you get in SensorEventListener.onSensorChanged(). I really hope you can complete my solution to help people who will have the same problems like me. Here is the code, i think you will understand it after reading it. Feel free to change it, the main idea was to implement several methods to send the orientation angles to the opengl view or any other target which would need it. method 1 to 4 are working, they are directly sending the rotationMatrix to the OpenGl view. all other methods are not working or buggy and i hope someone knows to get them working. i think the best method would be method 5 if it would work, because it would be the easiest to understand but i'm not sure how efficient it is. the complete code isn't optimized so i recommend to not use it as it is in your project. here it is: import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import javax.microedition.khronos.egl.EGL10; import javax.microedition.khronos.egl.EGLConfig; import javax.microedition.khronos.opengles.GL10; import static javax.microedition.khronos.opengles.GL10.*; import android.app.Activity; import android.content.Context; import android.content.pm.ActivityInfo; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.opengl.GLSurfaceView; import android.opengl.GLSurfaceView.Renderer; import android.os.Bundle; import android.util.Log; import android.view.WindowManager; /** * This class provides a basic demonstration of how to use the * {@link android.hardware.SensorManager SensorManager} API to draw a 3D * compass. */ public class SensorToOpenGlTests extends Activity implements Renderer, SensorEventListener { private static final boolean TRY_TRANSPOSED_VERSION = false; /* * MODUS overview: * * 1 - unbufferd data directly transfaired from the rotation matrix to the * modelview matrix * * 2 - buffered version of 1 where both acceleration and magnetometer are * buffered * * 3 - buffered version of 1 where only magnetometer is buffered * * 4 - buffered version of 1 where only acceleration is buffered * * 5 - uses the orientation sensor and sets the angles how to rotate the * camera with glrotate() * * 6 - uses the rotation matrix to calculate the angles * * 7 to 12 - every possibility how the rotationMatrix could be constructed * in SensorManager.getRotationMatrix (see * http://www.songho.ca/opengl/gl_anglestoaxes.html#anglestoaxes for all * possibilities) */ private static int MODUS = 2; private GLSurfaceView openglView; private FloatBuffer vertexBuffer; private ByteBuffer indexBuffer; private FloatBuffer colorBuffer; private SensorManager mSensorManager; private float[] rotationMatrix = new float[16]; private float[] accelGData = new float[3]; private float[] bufferedAccelGData = new float[3]; private float[] magnetData = new float[3]; private float[] bufferedMagnetData = new float[3]; private float[] orientationData = new float[3]; // private float[] mI = new float[16]; private float[] resultingAngles = new float[3]; private int mCount; final static float rad2deg = (float) (180.0f / Math.PI); private boolean mirrorOnBlueAxis = false; private boolean landscape; public SensorToOpenGlTests() { } /** Called with the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE); openglView = new GLSurfaceView(this); openglView.setRenderer(this); setContentView(openglView); } @Override protected void onResume() { // Ideally a game should implement onResume() and onPause() // to take appropriate action when the activity looses focus super.onResume(); openglView.onResume(); if (((WindowManager) getSystemService(WINDOW_SERVICE)) .getDefaultDisplay().getOrientation() == 1) { landscape = true; } else { landscape = false; } mSensorManager.registerListener(this, mSensorManager .getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_GAME); mSensorManager.registerListener(this, mSensorManager .getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD), SensorManager.SENSOR_DELAY_GAME); mSensorManager.registerListener(this, mSensorManager .getDefaultSensor(Sensor.TYPE_ORIENTATION), SensorManager.SENSOR_DELAY_GAME); } @Override protected void onPause() { // Ideally a game should implement onResume() and onPause() // to take appropriate action when the activity looses focus super.onPause(); openglView.onPause(); mSensorManager.unregisterListener(this); } public int[] getConfigSpec() { // We want a depth buffer, don't care about the // details of the color buffer. int[] configSpec = { EGL10.EGL_DEPTH_SIZE, 16, EGL10.EGL_NONE }; return configSpec; } public void onDrawFrame(GL10 gl) { // clear screen and color buffer: gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); // set target matrix to modelview matrix: gl.glMatrixMode(GL10.GL_MODELVIEW); // init modelview matrix: gl.glLoadIdentity(); // move camera away a little bit: if ((MODUS == 1) || (MODUS == 2) || (MODUS == 3) || (MODUS == 4)) { if (landscape) { // in landscape mode first remap the rotationMatrix before using // it with glMultMatrixf: float[] result = new float[16]; SensorManager.remapCoordinateSystem(rotationMatrix, SensorManager.AXIS_Y, SensorManager.AXIS_MINUS_X, result); gl.glMultMatrixf(result, 0); } else { gl.glMultMatrixf(rotationMatrix, 0); } } else { //in all other modes do the rotation by hand: gl.glRotatef(resultingAngles[1], 1, 0, 0); gl.glRotatef(resultingAngles[2], 0, 1, 0); gl.glRotatef(resultingAngles[0], 0, 0, 1); if (mirrorOnBlueAxis) { //this is needed for mode 6 to work gl.glScalef(1, 1, -1); } } //move the axis to simulate augmented behaviour: gl.glTranslatef(0, 2, 0); // draw the 3 axis on the screen: gl.glVertexPointer(3, GL_FLOAT, 0, vertexBuffer); gl.glColorPointer(4, GL_FLOAT, 0, colorBuffer); gl.glDrawElements(GL_LINES, 6, GL_UNSIGNED_BYTE, indexBuffer); } public void onSurfaceChanged(GL10 gl, int width, int height) { gl.glViewport(0, 0, width, height); float r = (float) width / height; gl.glMatrixMode(GL10.GL_PROJECTION); gl.glLoadIdentity(); gl.glFrustumf(-r, r, -1, 1, 1, 10); } public void onSurfaceCreated(GL10 gl, EGLConfig config) { gl.glDisable(GL10.GL_DITHER); gl.glClearColor(1, 1, 1, 1); gl.glEnable(GL10.GL_CULL_FACE); gl.glShadeModel(GL10.GL_SMOOTH); gl.glEnable(GL10.GL_DEPTH_TEST); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_COLOR_ARRAY); // load the 3 axis and there colors: float vertices[] = { 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1 }; float colors[] = { 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1 }; byte indices[] = { 0, 1, 0, 2, 0, 3 }; ByteBuffer vbb; vbb = ByteBuffer.allocateDirect(vertices.length * 4); vbb.order(ByteOrder.nativeOrder()); vertexBuffer = vbb.asFloatBuffer(); vertexBuffer.put(vertices); vertexBuffer.position(0); vbb = ByteBuffer.allocateDirect(colors.length * 4); vbb.order(ByteOrder.nativeOrder()); colorBuffer = vbb.asFloatBuffer(); colorBuffer.put(colors); colorBuffer.position(0); indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); } public void onAccuracyChanged(Sensor sensor, int accuracy) { } public void onSensorChanged(SensorEvent event) { // load the new values: loadNewSensorData(event); if (MODUS == 1) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); } if (MODUS == 2) { rootMeanSquareBuffer(bufferedAccelGData, accelGData); rootMeanSquareBuffer(bufferedMagnetData, magnetData); SensorManager.getRotationMatrix(rotationMatrix, null, bufferedAccelGData, bufferedMagnetData); } if (MODUS == 3) { rootMeanSquareBuffer(bufferedMagnetData, magnetData); SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, bufferedMagnetData); } if (MODUS == 4) { rootMeanSquareBuffer(bufferedAccelGData, accelGData); SensorManager.getRotationMatrix(rotationMatrix, null, bufferedAccelGData, magnetData); } if (MODUS == 5) { // this mode uses the sensor data recieved from the orientation // sensor resultingAngles = orientationData.clone(); if ((-90 > resultingAngles[1]) || (resultingAngles[1] > 90)) { resultingAngles[1] = orientationData[0]; resultingAngles[2] = orientationData[1]; resultingAngles[0] = orientationData[2]; } } if (MODUS == 6) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); final float[] anglesInRadians = new float[3]; SensorManager.getOrientation(rotationMatrix, anglesInRadians); if ((-90 < anglesInRadians[2] * rad2deg) && (anglesInRadians[2] * rad2deg < 90)) { // device camera is looking on the floor // this hemisphere is working fine mirrorOnBlueAxis = false; resultingAngles[0] = anglesInRadians[0] * rad2deg; resultingAngles[1] = anglesInRadians[1] * rad2deg; resultingAngles[2] = anglesInRadians[2] * -rad2deg; } else { mirrorOnBlueAxis = true; // device camera is looking in the sky // this hemisphere is mirrored at the blue axis resultingAngles[0] = (anglesInRadians[0] * rad2deg); resultingAngles[1] = (anglesInRadians[1] * rad2deg); resultingAngles[2] = (anglesInRadians[2] * rad2deg); } } if (MODUS == 7) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in x y z * order Rx*Ry*Rz */ resultingAngles[2] = (float) (Math.asin(rotationMatrix[2])); final float cosB = (float) Math.cos(resultingAngles[2]); resultingAngles[2] = resultingAngles[2] * rad2deg; resultingAngles[0] = -(float) (Math.acos(rotationMatrix[0] / cosB)) * rad2deg; resultingAngles[1] = (float) (Math.acos(rotationMatrix[10] / cosB)) * rad2deg; } if (MODUS == 8) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in z y x */ resultingAngles[2] = (float) (Math.asin(-rotationMatrix[8])); final float cosB = (float) Math.cos(resultingAngles[2]); resultingAngles[2] = resultingAngles[2] * rad2deg; resultingAngles[1] = (float) (Math.acos(rotationMatrix[9] / cosB)) * rad2deg; resultingAngles[0] = (float) (Math.asin(rotationMatrix[4] / cosB)) * rad2deg; } if (MODUS == 9) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in z x y * * note z axis looks good at this one */ resultingAngles[1] = (float) (Math.asin(rotationMatrix[9])); final float minusCosA = -(float) Math.cos(resultingAngles[1]); resultingAngles[1] = resultingAngles[1] * rad2deg; resultingAngles[2] = (float) (Math.asin(rotationMatrix[8] / minusCosA)) * rad2deg; resultingAngles[0] = (float) (Math.asin(rotationMatrix[1] / minusCosA)) * rad2deg; } if (MODUS == 10) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in y x z */ resultingAngles[1] = (float) (Math.asin(-rotationMatrix[6])); final float cosA = (float) Math.cos(resultingAngles[1]); resultingAngles[1] = resultingAngles[1] * rad2deg; resultingAngles[2] = (float) (Math.asin(rotationMatrix[2] / cosA)) * rad2deg; resultingAngles[0] = (float) (Math.acos(rotationMatrix[5] / cosA)) * rad2deg; } if (MODUS == 11) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in y z x */ resultingAngles[0] = (float) (Math.asin(rotationMatrix[4])); final float cosC = (float) Math.cos(resultingAngles[0]); resultingAngles[0] = resultingAngles[0] * rad2deg; resultingAngles[2] = (float) (Math.acos(rotationMatrix[0] / cosC)) * rad2deg; resultingAngles[1] = (float) (Math.acos(rotationMatrix[5] / cosC)) * rad2deg; } if (MODUS == 12) { SensorManager.getRotationMatrix(rotationMatrix, null, accelGData, magnetData); rotationMatrix = transpose(rotationMatrix); /* * this assumes that the rotation matrices are multiplied in x z y */ resultingAngles[0] = (float) (Math.asin(-rotationMatrix[1])); final float cosC = (float) Math.cos(resultingAngles[0]); resultingAngles[0] = resultingAngles[0] * rad2deg; resultingAngles[2] = (float) (Math.acos(rotationMatrix[0] / cosC)) * rad2deg; resultingAngles[1] = (float) (Math.acos(rotationMatrix[5] / cosC)) * rad2deg; } logOutput(); } /** * transposes the matrix because it was transposted (inverted, but here its * the same, because its a rotation matrix) to be used for opengl * * @param source * @return */ private float[] transpose(float[] source) { final float[] result = source.clone(); if (TRY_TRANSPOSED_VERSION) { result[1] = source[4]; result[2] = source[8]; result[4] = source[1]; result[6] = source[9]; result[8] = source[2]; result[9] = source[6]; } // the other values in the matrix are not relevant for rotations return result; } private void rootMeanSquareBuffer(float[] target, float[] values) { final float amplification = 200.0f; float buffer = 20.0f; target[0] += amplification; target[1] += amplification; target[2] += amplification; values[0] += amplification; values[1] += amplification; values[2] += amplification; target[0] = (float) (Math .sqrt((target[0] * target[0] * buffer + values[0] * values[0]) / (1 + buffer))); target[1] = (float) (Math .sqrt((target[1] * target[1] * buffer + values[1] * values[1]) / (1 + buffer))); target[2] = (float) (Math .sqrt((target[2] * target[2] * buffer + values[2] * values[2]) / (1 + buffer))); target[0] -= amplification; target[1] -= amplification; target[2] -= amplification; values[0] -= amplification; values[1] -= amplification; values[2] -= amplification; } private void loadNewSensorData(SensorEvent event) { final int type = event.sensor.getType(); if (type == Sensor.TYPE_ACCELEROMETER) { accelGData = event.values.clone(); } if (type == Sensor.TYPE_MAGNETIC_FIELD) { magnetData = event.values.clone(); } if (type == Sensor.TYPE_ORIENTATION) { orientationData = event.values.clone(); } } private void logOutput() { if (mCount++ > 30) { mCount = 0; Log.d("Compass", "yaw0: " + (int) (resultingAngles[0]) + " pitch1: " + (int) (resultingAngles[1]) + " roll2: " + (int) (resultingAngles[2])); } } }

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