const int pulsePin = A0;
int threshold = 515; // When the readings go above this number, it "counts" as a heartbeat

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

void loop() {
  int signal = analogRead(pulsePin);

  Serial.print(signal);  // This prints the value of the incoming signal.
  Serial.print(",");
  Serial.println(threshold);  // This prints the minimum value to "count" a heartbeat

  delay(50);
}