#include <Arduino.h>

#define TRIG_PIN 23
#define ECHO_PIN 18
unsigned long loop_count = 0;

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

void loop() {
  loop_count++;
  
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  
  unsigned long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;
  
  Serial.print("D:");
  Serial.print(distance);
  Serial.print("cm L:");
  Serial.println(loop_count);
  
  loop_count = 0;
  
  // Espera para 15Hz (66ms total)
  unsigned long start = millis();
  while(millis() - start < 66) {
    // Espera ativa (não bloqueante para outras tarefas)
  }
}