#define TRIGGER 13
#define ECHO 12
#define LED1 2


float medeDistancia(){
  digitalWrite(TRIGGER, LOW);
  delayMicroseconds(3);
  digitalWrite(TRIGGER, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER, LOW);
  int pulso = pulseIn(ECHO, HIGH);
  return pulso/58;
}

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  pinMode(TRIGGER, OUTPUT);
  pinMode(ECHO, INPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  float distancia = medeDistancia();
  Serial.println("Distância: " + (String) distancia);
  if(distancia < 50) digitalWrite(LED1, HIGH);
  else digitalWrite(LED1, LOW);
}