int Mode;
void setup() 
{
  Serial.begin(115200);
  pinMode (13,OUTPUT);
}

void loop() 
{
 int n = Serial.available();
 if (n>0)
 {
  byte C = Serial.read();
  Serial.write(C);
  if(C == '1')
    digitalWrite(13,1);
  if(C == '0')
    digitalWrite(13,0);
  Mode = C;
 }
 if (Mode == '2')
 {
    digitalWrite(13,1);
    delay(100);
    digitalWrite(13,0);
    delay(100);
 }
 if (Mode == '3')
 {
  digitalWrite(13,1);
    delay(1);
    digitalWrite(13,0);
    delay(10);
 }
 if (Mode == '4')
 {
  digitalWrite(13,1);
    delay(5);
    digitalWrite(13,0);
    delay(5);
 }
 delay(1);
}