int servoPin = 19;

void setup() {
  pinMode(servoPin, OUTPUT);
}

void loop() {
  // Move to 0 degree
  analogWrite(servoPin, 26);  
  delay(2000);

  // Move to 90 degree
  analogWrite(servoPin, 77);  
  delay(2000);

  // Move to 180 degree
  analogWrite(servoPin, 128); 
  delay(2000);
}