1. Android sensors

2. List of sensors Make new app. In onCreate add Nexus One Sensors
SensorManager sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
List<Sensor> list = sensorManager.getSensorList(Sensor.TYPE_ALL);
for (Sensor s : list) {
Log.e("SENSORS","name: "+s.getName()); }
Nexus One Sensors
BMA150 3-axis Accelerometer
AK axis Magnetic field sensor
AK8973 Orientation sensor
CM3602 Proximity sensor
CM3602 Light sensor
Linear Acceleration Sensor
Rotation Vector Sensor
Nexus S Sensors
KR3DM 3-axis Accelerometer
AK axis Magnetic field sensor
AK8973 Orientation sensor
GP2A Proximity sensor
GP2A Light sensor
Linear Acceleration Sensor
Rotation Vector Sensor
K3G Gyroscope sensor
Gravity Sensor
API also supports
pressure sensor (to help determine altitude)

3. compass New app: Compass Add member variables
SensorManager sensorManager;
Sensor compassSensor;
MyCompassListener myCompassListener = new MyCompassListener(); // we need to make this

4. MyCompassListener Make class Let eclipse add unimplemented functions
class MyCompassListener implements SensorEventListener {};
Let eclipse add unimplemented functions
In onSensorChanged(SensorEvent event), add
Log.e("compass","x: "+event.values[0]+"y: "+event.values[1]);

5. Register our sensor listener
In onCreate, get sensor and register listener
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
List<Sensor> list = sensorManager.getSensorList(Sensor.TYPE_ALL);
for (Sensor s : list) {
Log.e("SENSORS","name: "+s.getName()+" tpye: "+s.getType());
if (s.getType()==Sensor.TYPE_MAGNETIC_FIELD) {
Log.e("debuginfo","registering lin accel");
compassSensor = s;
sensorManager.registerListener(myCompassListener, s, sensorManager.SENSOR_DELAY_FASTEST); }
Run and see compass values

6. unregister and reregister
Sensors will keep on creating events, so we must stop the events when the app is not active
In main activity
@Override
public void onPause() {
super.onPause();
sensorManager.unregisterListener(myCompassListener); }
public void onResume() {
super.onResume();
sensorManager.registerListener(myCompassListener, compassSensor, sensorManager.SENSOR_DELAY_FASTEST);

7. Draw compass Recall simple drawing on a canvas lecture
In graphical editor, add “view” object.
Save
Go to xml and make the just made entry be of type edu.udel.eleg454.MyView instead of View
This requires replacing view and /view
Make new class
MyView that extends view
Add
public MyView(Context context, AttributeSet attrs) {
super(context, attrs); }
public MyView(Context context) {
super(context);

8. In MyView, add member variables
public float x=0;
public float y=1;
float scale;
In onDraw, add
Paint paint = new Paint();
paint.setDither(true);
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
paint.setStrokeWidth(2);
Now draw the compass
scale = (float) Math.sqrt(x*x+y*y); // normalize
x = x/scale*50;
y = y/scale*50;
canvas.drawLine(100,100,100+y,100+x, paint);

9. In Compass (our main activity class)
In onCreate, get the view
view = (MyView)findViewById(R.id.View01);
In onSensorChanged(SensorEvent event), add
view.x = event.values[0];
view.y = event.values[1];
view.invalidate(); // forces redraw
run

10. More sensors - Proximity
Make new app (or maybe canalized Compass)
Add member variables
SensorManager sensorManager;
Sensor sensor;
MySensorListener mySensorListener = new MySensorListener (); // we need to make this
In onCreate() add,
if (s.getType()==Sensor.TYPE_PROXIMITY) {
Log.e("debuginfo","registering lin accel");
compassSensor = s;
sensorManager.registerListener(myCompassListener, s, sensorManager.SENSOR_DELAY_FASTEST); }
Make MySensorListener as we made MyCompassListener
In onSensorChanged add
if (event.sensor.getType()==Sensor.TYPE_PROXIMITY) {
Log.e("Proximity ","x: "+event.values[0]);
Run
Try with light sensor
Sensor.TYPE_LIGHT

11. Linear Accelerometer Add local class
Make a linear accelerometer listener
Register listener
Add member variable
MyLinearAccelerationListener myLinearAccelerationListener = new MyLinearAccelerationListener();
Add local class
class MyLinearAccelerationListener implements SensorEventListener { };
Let eclipse add unimplemented methods
Add class member variables
double[] linear_acceleration = new double[3];
double[] location = new double[3];
double[] velocity = new double[3];
long lastTimeStamp = 0;
double timeDif;
In onSensorChanged(SensorEvent event) // make sure arg is called event
if (event.sensor.getType()==10) {
if (lastTimeStamp>0) {
// to do: add a jetPlayer-based sounds
timeDif = ((double)(event.timestamp - lastTimeStamp))/1e9;
velocity[0] = velocity[0] + timeDif*event.values[0];
velocity[1] = velocity[1] + timeDif*event.values[1];
velocity[2] = velocity[2] + timeDif*event.values[2];
location[0] = location[0] + timeDif*velocity[0];
location[1] = location[1] + timeDif*velocity[1];
location[2] = location[2] + timeDif*velocity[2];
locationView.setText("location x: "+((double)((int)(location[0]*10.0)))/10.0+ " y: "+ ((double)((int)(location[1]*10.0)))/10.0+" z: "+((double)((int)(location[2]*10.0)))/10.0);
velocityView.setText("velocity x: "+((double)((int)(velocity[0]*10.0)))/10.0+ " y: "+ ((double)((int)(velocity[1]*10.0)))/10.0+" z: "+((double)((int)(velocity[2]*10.0)))/10.0); }
lastTimeStamp = event.timestamp;

12. accelerometer linear_acceleration[0] = event.values[0] - gravity[0];
Challenge: remove gravity from measurement
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];
scale = Math.sqrt(gravity[0]*gravity[0] + gravity[1]*gravity[1] + gravity[2]*gravity[2])/SensorManager.GRAVITY_EARTH;
gravity[0] = gravity[0]/scale;
gravity[1] = gravity[1]/scale;
gravity[2] = gravity[2]/scale;
linear_acceleration[0] = event.values[0] - gravity[0];
linear_acceleration[1] = event.values[1] - gravity[1];
linear_acceleration[2] = event.values[2] - gravity[2];
SAME as linear accelerometer

13. todo Rotation sensor or gyroscope Gesture recognition
Show opengl image that rotates as phone rotates
E.g., see navigator
Allow phone to work as joystick
Gesture recognition
Hidden markov models
Location tracking
Keep history
Gryoscope (to track gravity)
Statistical signal processing