byte ledPin = 3, potentiometerPin = A1;
int oldPotVal, pwm;
unsigned long timer = 0, oldTime = 0, interval = 100; // reading interval in milliseconds

void setup() {
  Serial.begin(115200);
  delay(1000);
  Serial.println("Move potentiometer.");
}

void loop() {
  readPotentiometer(); // read the sensor without using delay();
}

void readPotentiometer() {
  int newPotVal = analogRead(potentiometerPin);
  if (millis() - oldTime > interval) { // compare event duration/difference to interval
    oldTime = millis(); // store the new event start
    if (newPotVal != oldPotVal) {
      analogWrite(ledPin, map(newPotVal, 0, 1023, 0, 255)); // PWM for LED
      Serial.print("AIN:"); // show the reading
      pad(newPotVal); // show the reading
      Serial.print("PWM:"); // show the reading
      pwm = map(newPotVal, 0, 1023, 0, 255);
      pad(pwm); // show the reading
      for (int i = 0; i < pwm / 5; i++)
        Serial.print("*");
      Serial.println();
    }
    oldPotVal = newPotVal;
  }
}

void pad(int value) {
  if (value < 1000) Serial.print(" ");
  if (value < 100) Serial.print(" ");
  if (value < 10) Serial.print(" ");
  Serial.print(value);
  Serial.print(" ");
}