#include "U8glib.h"
#include <Servo.h>

Servo myservo;
int potpin = 0;
int val;

U8GLIB_SSD1306_128X64 u8g(U8G_I2C_OPT_DEV_0 | U8G_I2C_OPT_NO_ACK | U8G_I2C_OPT_FAST); // Fast I2C / TWI

int progress = 0;
void setup() {
   myservo.attach(9); 
  u8g.setFont(u8g_font_tpssb);
  u8g.setColorIndex(1);
}

void loop() {

  val = analogRead(potpin);
  val = map(val, 0, 1023, 0, 180);  

  u8g.firstPage();
  do {
    u8g.drawStr(25, 50, "Progress Bar");
    u8g.drawFrame(0, 10, 128, 20);
    u8g.drawBox(10, 15, val, 10);
  } while ( u8g.nextPage() );

  if (val <= 180) {
    myservo.write(val);  
  } else if (val == 0) {
    myservo.write(90);  
  } 
}