int servoPin = 12;     // Control pin for servo motor
int pulseCero;        //let`s calibrate!
int maxPulse = 2300;  // Maximum servo position
int minPulse= -1300;      // Minimum servo position
int pulse = 0;        // Amount to pulse the servo

long lastPulse = 0;    // the time in milliseconds of the last pulse
int refreshTime = 20; // the time needed in between pulses

int analogValue = 0;  // the value returned from the analog sensor
int analogPin = 3;    // the analog pin that the sensor's on

void setup() {
  pinMode(servoPin, OUTPUT);  // Set servo pin as an output pin
  //pulse = pulseCero;           // Set the motor position value to the minimum
  Serial.begin(9600);
}

void loop() {
  analogValue = analogRead(analogPin);      // read the analog input
  Serial.print("Analog Value:");
  Serial.print (analogValue);
  pulse = map(analogValue,0,1023,minPulse,maxPulse);    // convert the analog value
  // to a range between minPulse
  // and maxPulse.

  // pulse the servo again if rhe refresh time (20 ms) have passed:
    digitalWrite(servoPin, HIGH);   // Turn the motor on
    delayMicroseconds(pulse);       // Length of the pulse sets the motor position
    digitalWrite(servoPin, LOW);    // Turn the motor off
    delayMicroseconds (refreshTime);
    Serial.print (" Pulse:");
    Serial.println (pulse);

}