receiver.ino

#define sampleRate 1
#define progChangeDuration 1000
#define threshold 20

void setup()
{
  pinMode(2, INPUT);
}

void loop()
{
  int rf_input = analogRead(1);
  if (rf_input > threshold)
    if(detectHigh()) {
      // send something to serial, then delay or whatever
    }
      
}

bool detectHigh()
{
  int time = progChangeDuration;
  int count = 0;
  while(time-->0) {
    if(analogRead(1) > threshold)
      count++;
    delay(sampleRate);
  }

  int totalCycles = progChangeDuration / sampleRate;
  int expectedHighCount = totalCycles/2;

  if(abs(count-expectedHighCount) < 40) {
    return true;
  } else {
    return false;
  }
}