trackscanner/src/de/neosoft/trackscanner/TrackScannerActivity.java

package de.neosoft.trackscanner;

import android.app.Activity;
import android.os.Bundle;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.widget.EditText;

public class TrackScannerActivity extends Activity implements SensorEventListener {
	private SensorManager sensorManager;
	private long lastUpdate;
	private EditText mEdit;
	private EditText mEdit2;
    private float[] linear_acceleration = new float[3];
    private float[] gravity = new float[3];
	
    private float[] mags = new float[3];
    private float[] accels = new float[3];
    private int matrix_size = 16;
    // matrices for letting SensorManager do its magic
    private float[] RotationMatrix = new float[matrix_size];
    private float[] InclinationMatrix = new float[matrix_size];
    
    private int delay;
    
	/** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        delay = SensorManager.SENSOR_DELAY_NORMAL;
        // delay = SensorManager.SENSOR_DELAY_FASTER;
        // delay = SensorManager.SENSOR_DELAY_FASTEST;
        // delay = SensorManager.SENSOR_DELAY_GAME;
        
        
		sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
		sensorManager.registerListener(this,
				sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
				delay);

		sensorManager.registerListener(this,
				sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
				delay);
	
		
		lastUpdate = System.currentTimeMillis();

		mEdit = (EditText)findViewById(R.id.editText1);
		mEdit2 = (EditText)findViewById(R.id.editText2);

    }
    
	@Override
	public void onSensorChanged(SensorEvent event) {

		 switch (event.sensor.getType()) {
		    case Sensor.TYPE_MAGNETIC_FIELD:
		      mags[0] = event.values[0];
		      mags[1] = event.values[1];
		      mags[2] = event.values[2];
		      break;
		    case Sensor.TYPE_ACCELEROMETER:
		      accels[0] = event.values[0];
		      accels[1] = event.values[1];
		      accels[2] = event.values[2];

		      //SensorManager.GRAVITY_EARTH
		        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];
		      break;
		 }
		 SensorManager.getRotationMatrix(RotationMatrix, InclinationMatrix,
				        accels, mags);
		 float orientation[] = new float[3];
		 SensorManager.getOrientation(RotationMatrix, orientation);
		 float azimut = orientation[0]; // orientation contains: azimut, p
		 float heading = (-azimut*360/(2*3.14159f)); // 0 = North -90=West, 90= East

		 mEdit.setText("Accelerometer action: "+
					"\nElevation Front/Back: "+gravity[0]+
					"\nElevation Left/Right: "+gravity[1]+
					"\nDrive Acceleration: "+linear_acceleration[0]+
					"\nDrift Force: "+linear_acceleration[1]+
					"\nVertical Force: "+linear_acceleration[2]
					
	        		);
	        	/*
	        	 *  GravX = front/back elevation grade (recalc to degrees)
	        	 *  GravY =  left/right evlevation grade
	        	 *  LinAccX = driving acceleration
	        	 *  LinAccY = drift acceleration
	        	 *  LinAccZ = vertical acceleration
	        	 */

		 float x = mags[0];
		 float y = mags[1];
		 float z = mags[2];
		 mEdit2.setText("Magnetic Field:"+
					"\nX = "+x+
					"\nY = "+y+
					"\nZ = "+z+
					"\nHeading: "+heading);

	}

	@Override
	public void onAccuracyChanged(Sensor sensor, int accuracy) {
		// TODO Auto-generated method stub

	}

	@Override
	protected void onResume() {
		super.onResume();
		// register this class as a listener for the orientation and
		// accelerometer sensors
		sensorManager.registerListener(this,
				sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
				delay);

		sensorManager.registerListener(this,
				sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
				delay);
	}

	@Override
	protected void onPause() {
		// unregister listener
		sensorManager.unregisterListener(this);
		super.onStop();
	}
}