title: Serial read only returns reverse question marks in Blutooth connection read
body: <p>I'm facing problem with my Arduino Bluetooth controller car.<br>
  I'm only getting reverse question marks.</p>
  
  <p>I'm using an HC-05 Bluetooth module. The pins are connected as following:</p>
  
  <ul>
  <li>HC 05 -> Arduino</li>
  <li>RX -> TX</li>
  <li>TX -> RX</li>
  <li>5V -> 5V</li>
  <li>GND -> GND</li>
  </ul>
  
  <p>Ardunio code:</p>
  
  <pre class="lang-cpp prettyprint-override"><code>#include &lt;AFMotor.h&gt;
  AF_DCMotor right_motor(3, MOTOR12_8KHZ);
  AF_DCMotor left_motor(4, MOTOR12_8KHZ);
  
  String readString;
  
  void setup() {
    Serial.begin(9600);
    right_motor.setSpeed(250);
    left_motor.setSpeed(250);
  }
  
  void loop() {
    while(Serial.available()){
      delay(50);
      char c=Serial.read();
      readString+=c;
    }
    if(readString.length()&gt;0){
      Serial.println(readString);
      if (readString =="FORWARD"){
        right_motor.run (FORWARD);
        left_motor.run (FORWARD);
        delay(500);
      }
      if (readString =="BACKWARD"){
        right_motor.run (BACKWARD);
        left_motor.run (BACKWARD);
        delay(500);
      }
      if (readString =="LEFT"){
        right_motor.run (FORWARD);
        left_motor.run (BACKWARD);
        delay(500);
      }
      if (readString =="RIGHT"){
        right_motor.run (BACKWARD);
        left_motor.run (FORWARD);
        delay(500);
      }
      if (readString =="STOP"){
        right_motor.run (RELEASE);
        left_motor.run (RELEASE);
        delay(500);
      }
  
      readString="";
    }
  }
  </code></pre>
  
  <p>Serial monitor:</p>
  
  <p><a href="https://i.stack.imgur.com/kZcsn.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kZcsn.jpg" alt="Serial monitor output"></a></p>
  
  <p>I have tried many types of changes in the code, but they are not working.</p>