#define ECHO_PIN 3
#define TRIG_PIN 2
void setup() {
  Serial.begin(115200);
  pinMode(13, OUTPUT);
  pinMode(12, OUTPUT);

  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}
float readDistanceCM(){
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void loop() {
  float distance = readDistanceCM() ;
  bool isNearby = distance < 100;
  digitalWrite(12, isNearby);
  digitalWrite(13, isNearby);

  Serial.println("Measured distance: ");
  Serial.println(readDistanceCM());
  delay(100);
}