char val;//the variable val uses caracters only
void setup()
{
  pinMode(5,OUTPUT);//set the pin 5 in samd11c as output
  digitalWrite(5,LOW);//set it to low at the begining of the sketch
  Serial.begin(115200);//start serial communications
}

void loop()
{
  val=Serial.read();//read the value of the serial monitor and store it on "val"
 switch (val)//swtch when the variable "val" changes to
 {  
 case '0': //character "0"
 digitalWrite(5,LOW);//set the pin to LOW
 Serial.println("you just turned OFF the Relay");//write this message on serial monitor
 break;
 case '1'://character "1"
 digitalWrite(5,HIGH);//set pin to high
 Serial.println("you just turned ON the Relay");//write this message on serial monitor
 break;
 }
}