#define SERVO_PIN         19  // Any pin on the Arduino or Gertboard will work.

void setup()
{
  pinMode(SERVO_PIN, OUTPUT);

}

int lenMicroSecondsOfPeriod = 20 * 1000; // 20 milliseconds (ms)
int minPulseWidth = 0.5 * 1000; //0,5 adalah minimum pulsa / sinyal dalam (ms)
int maxPulseWidth = 2.5 * 1000; //2,5 adalah maksimal pulsa / sinyal dalam (ms)
int increment = 0.02 * 1000; //variabel untuk penambahan nilai

void loop()
{
    int posisi = 0; 
    for(posisi = minPulseWidth; posisi < maxPulseWidth; posisi+=increment){
         // Servos work by sending a 20 ms pulse.  
         // 0.5 ms at the start of the pulse will turn the servo to the 0 degree position
         // 1.5 ms at the start of the pulse will turn the servo to the 90 degree position 
         // 2.4 ms at the start of the pulse will turn the servo to the 180 degree position 
         // Turn voltage high to start the period and pulse
         digitalWrite(SERVO_PIN, HIGH);

         // Delay for the length of the pulse
         delayMicroseconds(posisi);

         // Turn the voltage low for the remainder of the pulse
         digitalWrite(SERVO_PIN, LOW);

         // Delay this loop for the remainder of the period so we don't
         // send the next signal too soon or too late
         delayMicroseconds(lenMicroSecondsOfPeriod - posisi); 
    }
    for(posisi = maxPulseWidth; posisi > minPulseWidth; posisi-=increment){
         // Servos work by sending a 20 ms pulse.
         // 0.5 ms at the start of the pulse will turn the servo to the 0 degree position
         // 1.5 ms at the start of the pulse will turn the servo to the 90 degree position
         // 2.4 ms at the start of the pulse will turn the servo to the 180 degree position
         // Turn voltage high to start the period and pulse
         digitalWrite(SERVO_PIN, HIGH);

         // Delay for the length of the pulse
         delayMicroseconds(posisi);

         // Turn the voltage low for the remainder of the pulse
         digitalWrite(SERVO_PIN, LOW);

         // Delay this loop for the remainder of the period so we don't
         // send the next signal too soon or too late
         delayMicroseconds(lenMicroSecondsOfPeriod - posisi);
    }

}