ECG en Arduino

Ref. de youtube:

/*
//What is an analogical read: http://www.arduino.cc/en/Tutorial/AnalogReadSerial
*/References from youtube, ECG with Arduino:
//https://www.youtube.com/watch?reload=9&v=9Si4efa434U
//https://www.youtube.com/watch?v=xySBTU_9vGo

int L0Mas =11;
int L0Menos = 10;
int Senal =A0;

// the setup routine runs once when you press reset:
void setup() {

  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
pinMode(L0Mas, INPUT);
pinMode(L0Menos,INPUT);

}

// the loop routine runs over and over again forever:
void loop() {
  if ((digitalRead(L0Mas)==1) || (digitalRead(L0Menos)==1)){
  Serial.println('!');
  }
  else{
    Serial.println(analogRead(A0));
  // read the input on analog pin 0:
  //int sensorValue = analogRead(A0);
  // print out the value you read:
   // int sensorValue1 = digitalRead(11);
    // int sensorValue2 = digitalRead(12);
  //Serial.println(sensorValue+sensorValue1+sensorValue2);
//  delay(1);        // delay in between reads for stability
//https://www.youtube.com/watch?reload=9&v=9Si4efa434U
//Serial.println(1024/2);
  }
  delay(1);
  }

///