 AF_DCMotor motor2(2);
 AF_DCMotor motor3(3);
 AF_DCMotor motor4(4);
+
+#define TRIGGER_PIN  2
+#define ECHO_PIN     13
+#define MAX_DISTANCE 200
+
+NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);
 
 int motorSpeed = 100;
 bool isMovingForward = false;

  motor3.setSpeed(motorSpeed);
  motor4.setSpeed(motorSpeed);
}

  
  if(command == "battery") {
    result = checkBatteryStatus(argument);
  } else if(command == "distance") {
    result = getDistance(argument);
  } else if(command == "forward") {
    result = forward(argument);
  } else if(command == "backward") {
