#define m1 3
#define laser 13

int count=0;

int val = 0x00; //Valor entrada serie

void setup()                    
{
  Serial.begin(9600); 
  
  pinMode(m1, OUTPUT); 
  pinMode(laser, OUTPUT); 
  digitalWrite(m1, LOW);
  digitalWrite(laser, LOW);

}

void loop()                      //run over and over again
{  
  if (Serial.available()) {
    val = Serial.read();

    if (val==0x00) analogWrite(m1, 0);
    else if (val==0x01) analogWrite(m1, 50);
    else if (val==0x02) digitalWrite(laser, HIGH);
    else if (val==0x03) digitalWrite(laser, LOW);

  }
}