user46063: Sorry for doing this, I really don't know where to post beacuse this is both Android Studio code and Arduino code so I've posted to both sites.
I want to create a project of using controlling pan-tilt (2 servos combined) using the accelerometer and gyroscope data in smartphone. Creating Android app and sending the accelerometer and gryroscope data to Arduino so that the pan-tilt can determine its location.
My problem is when I connect the Android app to Arduino, no data is shown in serial monitor of Arduino and the pan-tilt is not locating the smartphone.
Please help me to solve this problem.
This MainActivity is the class to identify the data of accelerometer and gyrscope.
MainActivity:
public class MainActivity extends AppCompatActivity implements SensorEventListener{

    private final String TAG = "MainActivity";//log our activity

    SensorManager sm;//define sensor manager
    Sensor accelerometer, gyrometer;//define accelerometer

    TextView xValue, yValue, zValue, xGyroValue, yGyroValue, zGyroValue;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        xValue = (TextView)findViewById(R.id.xValue);
        yValue = (TextView)findViewById(R.id.yValue);
        zValue = (TextView)findViewById(R.id.zValue);

        xGyroValue = (TextView)findViewById(R.id.xGyroValue);
        yGyroValue = (TextView)findViewById(R.id.yGyroValue);
        zGyroValue = (TextView)findViewById(R.id.zGyroValue);

        Log.d(TAG, "onCreate: Initializing Sensor Services");

        sm =(SensorManager) getSystemService(Context.SENSOR_SERVICE);//permission to use the sensor

        accelerometer = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        if (accelerometer != null) {

            sm.registerListener(MainActivity.this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
            Log.d(TAG, "onCreate: Registered accelerometer listerner");
        }else {

            xValue.setText("accelerometer is not supported");
            yValue.setText("accelerometer is not supported");
            zValue.setText("accelerometer is not supported");
        }
        gyrometer = sm.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
        if (gyrometer != null) {

            sm.registerListener(MainActivity.this, gyrometer, SensorManager.SENSOR_DELAY_NORMAL);
            Log.d(TAG, "onCreate: Registered gyrometer listerner");
        }else {

            xGyroValue.setText("gyrometer is not supported");
            yGyroValue.setText("gyrometer is not supported");
            zGyroValue.setText("gyrometer is not supported");
        }
    }

    public void connect(View v){

        DataSender dataSender = new DataSender();
        dataSender.execute((String) xValue.getText(), toString());
        dataSender.execute((String) yValue.getText(), toString());
        dataSender.execute((String) zValue.getText(), toString());
        dataSender.execute((String) xGyroValue.getText(), toString());
        dataSender.execute((String) yGyroValue.getText(), toString());
        dataSender.execute((String) zGyroValue.getText(), toString());

    }

    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
        Sensor sensor = sensorEvent.sensor;
        if(sensor.getType() == Sensor.TYPE_ACCELEROMETER){

            Log.d(TAG, "onSensorChanged: X: " + sensorEvent.values[0] + "Y: " + sensorEvent.values[1] + "Z:" + sensorEvent.values[2]);

            xValue.setText("xValue:   " + sensorEvent.values[0]);
            yValue.setText("yValue:   " + sensorEvent.values[1]);
            zValue.setText("zValue:   " + sensorEvent.values[2]);
        }else if (sensor.getType() == Sensor.TYPE_GYROSCOPE){

            xGyroValue.setText("xGyroValue:   " + sensorEvent.values[0]);
            yGyroValue.setText("yGyroValue:   " + sensorEvent.values[1]);
            zGyroValue.setText("zGyroValue:   " + sensorEvent.values[2]);

        }

    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }
}

This DataSender is the class for sending the data to Arduino.
DataSender:
public class DataSender extends AsyncTask<String, Void, Void> {

    Socket s;
    DataOutputStream dos;
    PrintWriter pw;

    @Override
    protected Void doInBackground(String... voids) {

        String data = voids[0];

        try {
            s = new Socket("192.168.1.100",80);
            pw = new PrintWriter(s.getOutputStream());
            pw.write(data);
            pw.flush();
            pw.close();
            s.close();

        } catch (IOException e){
            e.printStackTrace();
        }

        return null;
    }
}

This is code that are uploaded in wifi module (esp8266-01) that are connected in Arduino.
Arduino code:
#include <SoftwareSerial.h>
#include <Servo.h>

#define DEBUG true

SoftwareSerial esp8266(10, 11); // RX, TX

char tiltChannel=0, panChannel=1;

//These are the objects for each servo.
Servo servoTilt, servoPan;

//This is a character that will hold data from the Serial port.
char serialChar=0;

// Center servos
int tiltVal = 90; 
int panVal =90; 

//smaartphone value
String inText;
float value0, value1, value2;


void setup() { // Open serial communications and wait for port to open:

  servoTilt.attach(2);  //The Tilt servo is attached to pin 2.
  servoPan.attach(3);   //The Pan servo is attached to pin 3.
  servoTilt.write(90);  //Initially put the servos both
  servoPan.write(90);      //at 90 degress.

  Serial.begin(9600); //for monitoring purposes
  esp8266.begin(9600);

  //sendCommand("AT+CIFS+RST\r\n", 2000, DEBUG); // reset module
  sendCommand("AT+IPR=9600\r\n", 1000, DEBUG);
  sendCommand("AT+CWMODE=1\r\n", 1000, DEBUG); // configure as access point
  sendCommand("AT+CWJAP=\"EceConnect\",\"1234\"\r\n", 3000, DEBUG); //connec to 
a network with name EceConnect with password 1234
  delay(1000);
  sendCommand("AT+CIFSR\r\n", 1000, DEBUG); // get ip address
  sendCommand("AT+CIPSTA=\"192.168.1.100\"\r\n", 1000, DEBUG);
  sendCommand("AT+CIPMUX=1\r\n", 1000, DEBUG); // configure for multiple 
connections
  sendCommand("AT+CIPSERVER=1,80\r\n", 1000, DEBUG); // turn on server on port 
80
  Serial.println("Server Ready");

  Serial.println("Android Sensor Type No: ");
  Serial.println("1- ACCELEROMETER  (m/s^2 - X,Y,Z)");
  Serial.println("2- GYROSCOPE (rad/s - X,Y,Z)");
  Serial.flush();

}

void loop() { // run over and over

  Serial.flush();
  int inCommand = 0;
  int sensorType = 0;
  unsigned long logCount = 0L;

  if (Serial.available() < 1) return; // if serial empty, return to loop().

    char getChar = ' '; 
    if (esp8266.available()) {
      if (esp8266.find("+IPD,0,")) {
        delay(10);
        esp8266.find(":");
        delay(10);
        char letter = esp8266.read();
        Serial.print(letter); //for monitoring purposes
        //Gets the value/char from android app
      }
    }

    // parse incoming command start flag

    if (getChar != serialChar) return; // if no command start flag, return to 
loop().

    // parse incoming pin# and value 
    sensorType = Serial.parseInt(); // read sensor typr
    logCount = Serial.parseInt();  // read total logged sensor readings
    value0 = Serial.parseFloat();  // 1st sensor value
    value1 = Serial.parseFloat();  // 2rd sensor value if exists
    value2 = Serial.parseFloat();  // 3rd sensor value if exists

    // send smartphone readings to serial monitor/terminal
    if (DEBUG) {
      Serial.print("Sensor type: ");
      Serial.println(sensorType);
      Serial.print("Sensor log#: ");
      Serial.println(logCount);
      Serial.print("Val[0]: ");
      Serial.println(value0);
      Serial.print("Val[1]: ");
      Serial.println(value1);
      Serial.print("Val[2]: ");
      Serial.println(value2);
      Serial.println("-----------------------");
      delay(10);
    }

    // Check sensor type. If not for  Accelerometer (#1) then ignore readings
    // sensorType 1 is the Accelerometer sensor

  if (sensorType !=1) return;   

  panVal = value0; // value0 = X sensor reading
  tiltVal = value1;  // value1 = Y sensor reading

  tiltVal = map(tiltVal, 10, -10, 0, 179);   // Map Accelerometer Y value to 
tilt servo angle. 
  servoTilt.write(tiltVal);
  delay(10);

  panVal = map(panVal, -10, 10, 0, 179);  // Map Accelerometer X value to pan 
servo angle.
  servoPan.write(panVal);     
  delay(10); 
}


String sendCommand(String command, const int timeout, boolean debug) {
  String response = "";
  esp8266.print(command); // send the read character to the esp8266
  long int time = millis();
  while ((time + timeout) > millis()) {
    while (esp8266.available()) {
      // The esp has data so display its output to the serial window
      char c = esp8266.read(); // read the next character.
      response += c;
    }
  }

  if (debug) {
    Serial.print(response);
  }
  return response;
}


user8622: In the loop function you have a line 
If (Serial.available() < 1) return;

This prevents further code to be processed if there is nothing in the hardware serial buffer. Think about that. 

46063: <p>Sorry for doing this, I really don't know where to post beacuse this is both Android Studio code and Arduino code so I've posted to both sites.</p>

<p>I want to create a project of using controlling pan-tilt (2 servos combined) using the accelerometer and gyroscope data in smartphone. Creating Android app and sending the accelerometer and gryroscope data to Arduino so that the pan-tilt can determine its location.</p>

<p>My problem is when I connect the Android app to Arduino, no data is shown in serial monitor of Arduino and the pan-tilt is not locating the smartphone.
Please help me to solve this problem.</p>

<p>This <em>MainActivity</em> is the class to identify the data of accelerometer and gyrscope.</p>

<p>MainActivity:</p>

<pre><code>public class MainActivity extends AppCompatActivity implements SensorEventListener{

    private final String TAG = "MainActivity";//log our activity

    SensorManager sm;//define sensor manager
    Sensor accelerometer, gyrometer;//define accelerometer

    TextView xValue, yValue, zValue, xGyroValue, yGyroValue, zGyroValue;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        xValue = (TextView)findViewById(R.id.xValue);
        yValue = (TextView)findViewById(R.id.yValue);
        zValue = (TextView)findViewById(R.id.zValue);

        xGyroValue = (TextView)findViewById(R.id.xGyroValue);
        yGyroValue = (TextView)findViewById(R.id.yGyroValue);
        zGyroValue = (TextView)findViewById(R.id.zGyroValue);

        Log.d(TAG, "onCreate: Initializing Sensor Services");

        sm =(SensorManager) getSystemService(Context.SENSOR_SERVICE);//permission to use the sensor

        accelerometer = sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        if (accelerometer != null) {

            sm.registerListener(MainActivity.this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
            Log.d(TAG, "onCreate: Registered accelerometer listerner");
        }else {

            xValue.setText("accelerometer is not supported");
            yValue.setText("accelerometer is not supported");
            zValue.setText("accelerometer is not supported");
        }
        gyrometer = sm.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
        if (gyrometer != null) {

            sm.registerListener(MainActivity.this, gyrometer, SensorManager.SENSOR_DELAY_NORMAL);
            Log.d(TAG, "onCreate: Registered gyrometer listerner");
        }else {

            xGyroValue.setText("gyrometer is not supported");
            yGyroValue.setText("gyrometer is not supported");
            zGyroValue.setText("gyrometer is not supported");
        }
    }

    public void connect(View v){

        DataSender dataSender = new DataSender();
        dataSender.execute((String) xValue.getText(), toString());
        dataSender.execute((String) yValue.getText(), toString());
        dataSender.execute((String) zValue.getText(), toString());
        dataSender.execute((String) xGyroValue.getText(), toString());
        dataSender.execute((String) yGyroValue.getText(), toString());
        dataSender.execute((String) zGyroValue.getText(), toString());

    }

    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {
        Sensor sensor = sensorEvent.sensor;
        if(sensor.getType() == Sensor.TYPE_ACCELEROMETER){

            Log.d(TAG, "onSensorChanged: X: " + sensorEvent.values[0] + "Y: " + sensorEvent.values[1] + "Z:" + sensorEvent.values[2]);

            xValue.setText("xValue:   " + sensorEvent.values[0]);
            yValue.setText("yValue:   " + sensorEvent.values[1]);
            zValue.setText("zValue:   " + sensorEvent.values[2]);
        }else if (sensor.getType() == Sensor.TYPE_GYROSCOPE){

            xGyroValue.setText("xGyroValue:   " + sensorEvent.values[0]);
            yGyroValue.setText("yGyroValue:   " + sensorEvent.values[1]);
            zGyroValue.setText("zGyroValue:   " + sensorEvent.values[2]);

        }

    }

    @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy) {

    }
}
</code></pre>

<p>This DataSender is the class for sending the data to Arduino.</p>

<p>DataSender:</p>

<pre><code>public class DataSender extends AsyncTask&lt;String, Void, Void&gt; {

    Socket s;
    DataOutputStream dos;
    PrintWriter pw;

    @Override
    protected Void doInBackground(String... voids) {

        String data = voids[0];

        try {
            s = new Socket("192.168.1.100",80);
            pw = new PrintWriter(s.getOutputStream());
            pw.write(data);
            pw.flush();
            pw.close();
            s.close();

        } catch (IOException e){
            e.printStackTrace();
        }

        return null;
    }
}
</code></pre>

<p>This is code that are uploaded in wifi module (esp8266-01) that are connected in Arduino.</p>

<p>Arduino code:</p>

<pre><code>#include &lt;SoftwareSerial.h&gt;
#include &lt;Servo.h&gt;

#define DEBUG true

SoftwareSerial esp8266(10, 11); // RX, TX

char tiltChannel=0, panChannel=1;

//These are the objects for each servo.
Servo servoTilt, servoPan;

//This is a character that will hold data from the Serial port.
char serialChar=0;

// Center servos
int tiltVal = 90; 
int panVal =90; 

//smaartphone value
String inText;
float value0, value1, value2;


void setup() { // Open serial communications and wait for port to open:

  servoTilt.attach(2);  //The Tilt servo is attached to pin 2.
  servoPan.attach(3);   //The Pan servo is attached to pin 3.
  servoTilt.write(90);  //Initially put the servos both
  servoPan.write(90);      //at 90 degress.

  Serial.begin(9600); //for monitoring purposes
  esp8266.begin(9600);

  //sendCommand("AT+CIFS+RST\r\n", 2000, DEBUG); // reset module
  sendCommand("AT+IPR=9600\r\n", 1000, DEBUG);
  sendCommand("AT+CWMODE=1\r\n", 1000, DEBUG); // configure as access point
  sendCommand("AT+CWJAP=\"EceConnect\",\"1234\"\r\n", 3000, DEBUG); //connec to 
a network with name EceConnect with password 1234
  delay(1000);
  sendCommand("AT+CIFSR\r\n", 1000, DEBUG); // get ip address
  sendCommand("AT+CIPSTA=\"192.168.1.100\"\r\n", 1000, DEBUG);
  sendCommand("AT+CIPMUX=1\r\n", 1000, DEBUG); // configure for multiple 
connections
  sendCommand("AT+CIPSERVER=1,80\r\n", 1000, DEBUG); // turn on server on port 
80
  Serial.println("Server Ready");

  Serial.println("Android Sensor Type No: ");
  Serial.println("1- ACCELEROMETER  (m/s^2 - X,Y,Z)");
  Serial.println("2- GYROSCOPE (rad/s - X,Y,Z)");
  Serial.flush();

}

void loop() { // run over and over

  Serial.flush();
  int inCommand = 0;
  int sensorType = 0;
  unsigned long logCount = 0L;

  if (Serial.available() &lt; 1) return; // if serial empty, return to loop().

    char getChar = ' '; 
    if (esp8266.available()) {
      if (esp8266.find("+IPD,0,")) {
        delay(10);
        esp8266.find(":");
        delay(10);
        char letter = esp8266.read();
        Serial.print(letter); //for monitoring purposes
        //Gets the value/char from android app
      }
    }

    // parse incoming command start flag

    if (getChar != serialChar) return; // if no command start flag, return to 
loop().

    // parse incoming pin# and value 
    sensorType = Serial.parseInt(); // read sensor typr
    logCount = Serial.parseInt();  // read total logged sensor readings
    value0 = Serial.parseFloat();  // 1st sensor value
    value1 = Serial.parseFloat();  // 2rd sensor value if exists
    value2 = Serial.parseFloat();  // 3rd sensor value if exists

    // send smartphone readings to serial monitor/terminal
    if (DEBUG) {
      Serial.print("Sensor type: ");
      Serial.println(sensorType);
      Serial.print("Sensor log#: ");
      Serial.println(logCount);
      Serial.print("Val[0]: ");
      Serial.println(value0);
      Serial.print("Val[1]: ");
      Serial.println(value1);
      Serial.print("Val[2]: ");
      Serial.println(value2);
      Serial.println("-----------------------");
      delay(10);
    }

    // Check sensor type. If not for  Accelerometer (#1) then ignore readings
    // sensorType 1 is the Accelerometer sensor

  if (sensorType !=1) return;   

  panVal = value0; // value0 = X sensor reading
  tiltVal = value1;  // value1 = Y sensor reading

  tiltVal = map(tiltVal, 10, -10, 0, 179);   // Map Accelerometer Y value to 
tilt servo angle. 
  servoTilt.write(tiltVal);
  delay(10);

  panVal = map(panVal, -10, 10, 0, 179);  // Map Accelerometer X value to pan 
servo angle.
  servoPan.write(panVal);     
  delay(10); 
}


String sendCommand(String command, const int timeout, boolean debug) {
  String response = "";
  esp8266.print(command); // send the read character to the esp8266
  long int time = millis();
  while ((time + timeout) &gt; millis()) {
    while (esp8266.available()) {
      // The esp has data so display its output to the serial window
      char c = esp8266.read(); // read the next character.
      response += c;
    }
  }

  if (debug) {
    Serial.print(response);
  }
  return response;
}
</code></pre>
 8622: <p>In the <code>loop</code> function you have a line </p>

<pre><code>If (Serial.available() &lt; 1) return;
</code></pre>

<p>This prevents further code to be processed if there is nothing in the hardware serial buffer. Think about that. </p>
