#include <Servo.h>

Servo myservo;

int potentioPIN = A0;
int value;
void setup() {
  // put your setup code here, to run once:
  myservo.attach(9);
}

void loop() {
  // put your main code here, to run repeatedly:
  value = analogRead(potentioPIN);
  value = map(value,0,1023,0,180);
  myservo.write(value);
  delay(1000);

  value = map(value,1023,0,180,0);
  myservo.write(value);
  delay(1000);
}