SensorFilteredValuesActivity.java
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import android.app.Activity; import android.hardware.Sensor; import android.hardware.SensorEvent; import android.hardware.SensorEventListener; import android.hardware.SensorManager; import android.os.Bundle; import android.widget.TextView; public class SensorFilteredValuesActivity extends Activity implements SensorEventListener { // References to SensorManager and accelerometer private SensorManager mSensorManager; private Sensor mAccelerometer; // Filtering constant private final float mAlpha = 0.8f; // Arrays for storing filtered values private float[] mGravity = new float[3]; private float[] mAccel = new float[3]; private TextView mXValueView, mYValueView, mZValueView, mXGravityView, mYGravityView, mZGravityView, mXAccelView, mYAccelView, mZAccelView; private long mLastUpdate; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mXValueView = (TextView) findViewById(R.id.x_value_view); mYValueView = (TextView) findViewById(R.id.y_value_view); mZValueView = (TextView) findViewById(R.id.z_value_view); mXGravityView = (TextView) findViewById(R.id.x_lowpass_view); mYGravityView = (TextView) findViewById(R.id.y_lowpass_view); mZGravityView = (TextView) findViewById(R.id.z_lowpass_view); mXAccelView = (TextView) findViewById(R.id.x_highpass_view); mYAccelView = (TextView) findViewById(R.id.y_highpass_view); mZAccelView = (TextView) findViewById(R.id.z_highpass_view); // Get reference to SensorManager mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE); // Get reference to Accelerometer if (null == (mAccelerometer = mSensorManager .getDefaultSensor(Sensor.TYPE_ACCELEROMETER))) finish(); mLastUpdate = System.currentTimeMillis(); } // Register listener @Override protected void onResume() { super.onResume(); mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_UI); } // Unregister listener @Override protected void onPause() { super.onPause(); mSensorManager.unregisterListener(this); } // Process new reading @Override public void onSensorChanged(SensorEvent event) { if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) { long actualTime = System.currentTimeMillis(); if (actualTime - mLastUpdate > 500) { mLastUpdate = actualTime; float rawX = event.values[0]; float rawY = event.values[1]; float rawZ = event.values[2]; // Apply low-pass filter mGravity[0] = lowPass(rawX, mGravity[0]); mGravity[1] = lowPass(rawY, mGravity[1]); mGravity[2] = lowPass(rawZ, mGravity[2]); // Apply high-pass filter mAccel[0] = highPass(rawX, mGravity[0]); mAccel[1] = highPass(rawY, mGravity[1]); mAccel[2] = highPass(rawZ, mGravity[2]); mXValueView.setText(String.valueOf(rawX)); mYValueView.setText(String.valueOf(rawY)); mZValueView.setText(String.valueOf(rawZ)); mXGravityView.setText(String.valueOf(mGravity[0])); mYGravityView.setText(String.valueOf(mGravity[1])); mZGravityView.setText(String.valueOf(mGravity[2])); mXAccelView.setText(String.valueOf(mAccel[0])); mYAccelView.setText(String.valueOf(mAccel[1])); mZAccelView.setText(String.valueOf(mAccel[2])); } } } // Deemphasize transient forces private float lowPass(float current, float gravity) { return gravity * mAlpha + current * (1 - mAlpha); } // Deemphasize constant forces private float highPass(float current, float gravity) { return current - gravity; } @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { // NA } } |
main.xml
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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="vertical" > <TableLayout android:id="@+id/tableLayout1" android:layout_width="match_parent" android:layout_height="wrap_content" > <TableRow android:id="@+id/tableRow1" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="Raw X:" android:textSize="24sp" /> <TextView android:id="@+id/x_value_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow2" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="Raw Y:" android:textSize="24sp" /> <TextView android:id="@+id/y_value_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow3" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="Raw Z:" android:textSize="24sp" /> <TextView android:id="@+id/z_value_view" android:textSize="24sp" android:paddingBottom="10dp"/> </TableRow> <TableRow android:id="@+id/tableRow4" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="LowPass X" android:textSize="24sp" /> <TextView android:id="@+id/x_lowpass_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow5" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="LowPass Y:" android:textSize="24sp" /> <TextView android:id="@+id/y_lowpass_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow6" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="LowPass Z:" android:textSize="24sp" /> <TextView android:id="@+id/z_lowpass_view" android:textSize="24sp" android:paddingBottom="10dp"/> </TableRow> <TableRow android:id="@+id/tableRow7" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="HighPass X" android:textSize="24sp" /> <TextView android:id="@+id/x_highpass_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow8" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="HighPass Y:" android:textSize="24sp" /> <TextView android:id="@+id/y_highpass_view" android:textSize="24sp" /> </TableRow> <TableRow android:id="@+id/tableRow9" android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:text="HighPass Z:" android:textSize="24sp" /> <TextView android:id="@+id/z_highpass_view" android:textSize="24sp" /> </TableRow> </TableLayout> </LinearLayout> |