//Rotary controls LED
int rotaryPin = A0;    // select the input pin for the rotary
int ledPin = 4;      // select the pin for the LED
int rotaryValue = 0;  // variable to store the value coming from the rotary

void setup() {
  // declare the ledPin as an OUTPUT:
  pinMode(ledPin, OUTPUT);
  pinMode(rotaryPin, INPUT);
}

void loop() {
  // read the value from the sensor:
  rotaryValue = analogRead(rotaryPin);
  // turn the ledPin on
  digitalWrite(ledPin, HIGH);
  // stop the program for <sensorValue> milliseconds:
  delay(rotaryValue);
  // turn the ledPin off:
  digitalWrite(ledPin, LOW);
  // stop the program for for <sensorValue> milliseconds:
  delay(rotaryValue);
}