float dutyCycle = 0.4;
float currentDutyCycle = 0;

boolean filterOpen = false;
boolean newWave = true;

int inputPin = 6;
int outputPin = 5;

int lastInputValue = 0;
int inputValue = 0;

unsigned long inputStartTime = 0;
unsigned long inputSwitchTime = 0;
unsigned long inputEndTime = 0;


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

  pinMode(inputPin, INPUT);
  pinMode(outputPin, OUTPUT);

  //Wait for first signal
  while ( digitalRead(inputPin) != HIGH ) {};

  Serial.println("Filter initializing!");
}


void loop() {
  inputValue = digitalRead(inputPin);

  if (inputValue != lastInputValue) {
    if (inputValue == 1) {
      inputEndTime = millis();
      Serial.println("HIGH");
      currentDutyCycle = ( (float)inputSwitchTime - inputStartTime) / (inputEndTime - inputStartTime);
      Serial.print("Duty cycle: ");
      Serial.print(" inputStartTime: ");
      Serial.print(inputStartTime);
      Serial.print(" inputSwitchTime: ");
      Serial.print(inputSwitchTime);
      Serial.print(" inputEndTime: ");
      Serial.print(inputEndTime);
      Serial.print("Duty cycle: ");
      Serial.println((inputSwitchTime - inputStartTime) / (inputEndTime - inputStartTime));
      inputStartTime = inputEndTime;
    } else { //Switch
      inputSwitchTime = millis();
      Serial.println("LOW");
    }
    lastInputValue = inputValue;
  }

  if (currentDutyCycle >= dutyCycle) {
    filterOpen = true;
  } else {
    filterOpen = false;
  }

  if (filterOpen) {
    digitalWrite(outputPin, inputValue);
  } else {
    digitalWrite(outputPin, LOW);
  }

  /*
  Serial.print("Input is: ");
  Serial.print(inputValue);

  Serial.print(" Reading: ");
  Serial.print(digitalRead(inputPin));

  Serial.print("  Duty: ");
  Serial.print(currentDutyCycle);

  Serial.print(" Time data: ");
  Serial.println( inputEndTime - inputStartTime );
  */
}