const int analogInPin = A0; // Analog input pin that the potentiometer is attached to
const int analogOutPin = 9; // Analog output pin that the LED is attached to

int sensorValue = 0;        // value read from the pot
int referenceValue = 128;   // default output value
int varianceValue = 0;      // how far may the outputValue deviate from the referenceValue? 
int outputValue = 0;        // value output to the PWM (analog out)

void setup() {
  Serial.begin(9600);
}

void loop() {
  sensorValue = analogRead(analogInPin);  
  varianceValue = map(sensorValue, 0, 1023, 0, 127);
  outputValue = random(referenceValue - varianceValue, referenceValue + varianceValue);
  analogWrite(analogOutPin, outputValue);

  Serial.print("sensor:");
  Serial.print(sensorValue);
  Serial.print(",output:");
  Serial.println(outputValue);

  delay(5000 - sensorValue*3);
}