Accelerometer sensor in android

Accelerometer sensor in android

Accelerometer sensor android is used to detect the motion event in the Android devices, using the android sensor manager.

Here, is the simple steps to find the motion events in android.

1. Register the sensorListener in the starting of the activity.
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mSensorManager.registerListener(this, mAccelerometer , SensorManager.SENSOR_DELAY_NORMAL);

2. Implements SensorEventListener with the Activity

3. get the x,y,z values from the onSensorChanged Event,
float x = event.values[0];
float y = event.values[1];
float z = event.values[2];

4. Finally, UnRegister the sensorListener when pause() the activity,

mSensorManager.unregisterListener(this);
Full MainActivity.java
import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity implements SensorEventListener {

    private float mLastX, mLastY, mLastZ;
    private boolean mInitialized;
    private SensorManager mSensorManager;
    private Sensor mAccelerometer;
    private final float NOISE = (float) 2.0;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mInitialized = false;
        mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
        mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        mSensorManager.registerListener(this, mAccelerometer , SensorManager.SENSOR_DELAY_NORMAL);
    }

    protected void onResume() {
        super.onResume();
        mSensorManager.registerListener(this, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
    }

    protected void onPause() {
        super.onPause();
        mSensorManager.unregisterListener(this);
    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {
        // can be safely ignored for this demo
    }

    @Override
    public void onSensorChanged(SensorEvent event) {
        TextView tvX= (TextView)findViewById(R.id.x_axis);
        TextView tvY= (TextView)findViewById(R.id.y_axis);
        TextView tvZ= (TextView)findViewById(R.id.z_axis);
        ImageView iv = (ImageView)findViewById(R.id.image);
        float x = event.values[0];
        float y = event.values[1];
        float z = event.values[2];
        if (!mInitialized) {
            mLastX = x;
            mLastY = y;
            mLastZ = z;
            tvX.setText("0.0");
            tvY.setText("0.0");
            tvZ.setText("0.0");
            mInitialized = true;
        } else {
            float deltaX = Math.abs(mLastX - x);
            float deltaY = Math.abs(mLastY - y);
            float deltaZ = Math.abs(mLastZ - z);
            if (deltaX < NOISE) deltaX = (float)0.0;
            if (deltaY < NOISE) deltaY = (float)0.0;
            if (deltaZ < NOISE) deltaZ = (float)0.0;
            mLastX = x;
            mLastY = y;
            mLastZ = z;
            tvX.setText(Float.toString(deltaX));
            tvY.setText(Float.toString(deltaY));
            tvZ.setText(Float.toString(deltaZ));
            iv.setVisibility(View.VISIBLE);
            if (deltaX > deltaY) {
                iv.setImageResource(R.drawable.horizontal);
            } else if (deltaY > deltaX) {
                iv.setImageResource(R.drawable.vertical);
            } else {
                iv.setVisibility(View.INVISIBLE);
            }
        }
    }
}

Screenshot

Accelerometer sensor
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