byte flag=0;
int ledState = 0;
int interval = 1000;
long previousMillis = 0;

int rele = 8;
int led = 13;
int mode = 5;

//int pulsador = ... ;
//int clock_pin = 8;
//int clock_gnd = 9;


byte val = 0x00;

void setup() 
{
  Serial.begin(19200); 
  
  pinMode(rele, OUTPUT); 
  pinMode(mode, INPUT); 
  pinMode(led, OUTPUT);
  
//  pinMode(mode, INPUT);
//  pinMode(clock_pin, OUTPUT);
//  pinMode(clock_gnd, OUTPUT);

  digitalWrite(rele, LOW);
  digitalWrite(mode, HIGH);
  digitalWrite(led, HIGH);
  
//  digitalWrite(mode, HIGH);
//  digitalWrite(clock_gnd, LOW);
//  digitalWrite(clock_pin, HIGH);
//  delay(100);
//  digitalWrite(clock_pin, LOW);

}

void loop() 
{ 
  /*
  if (!digitalRead(pulsador))
  {
    Serial.print(0, BYTE); // activado
  }
  else if (digitalRead(pulsador))
  {
    Serial.print(1, BYTE); // desactivado
  }
*/
  
  if (!digitalRead(mode))
  {

    if (millis() - previousMillis > interval) 
    {
      previousMillis = millis();

      if (ledState == LOW)
        ledState = HIGH;
      else
        ledState = LOW;
        
      Serial.write(2); // modo automatico
      digitalWrite(led, ledState);
      delay(1000);
    }
  }
  else if (digitalRead(mode))
  {
    Serial.write(3); // modo manual
    digitalWrite(led, HIGH);
    delay(1000);
  }

 
  
  if(Serial.available() > 0)
  {
    val = Serial.read();
    if (val == 0x10) digitalWrite(rele,HIGH);
    else if (val == 0x20)  digitalWrite(rele, LOW);  
 //   else if (val==0x30) 
 //   {
 //     digitalWrite(clock_pin, HIGH);
 //     delay(100);
 //     digitalWrite(clock_pin, LOW);
 //   }
  
  }
  
}