Marcha Ré

  // http://labdegaragem.com/forum/topics/duvidas-altera-o-de-frequencia-no-buzzer-sensor-ultrassonico

  #define trigPin 13            // Pino de disparo do US
  #define echoPin 12            // Pino de leitura do US
  #define led 11                // Pino Led indicativo 1
  #define led2 10               // Pino Led indicativo2
  #define led3 5                // Pino Led indicativo 3
  #define pinBuzzer 7           // Pino saída buzzer

  void setup() {
    Serial.begin (9600);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);
    pinMode(led, OUTPUT);
    pinMode(led2, OUTPUT);
    pinMode(led3,OUTPUT);
    pinMode(pinBuzzer,OUTPUT);
  }

  void loop() {
    long duration, distance;
    digitalWrite(trigPin, LOW);
    delayMicroseconds(2);
    digitalWrite(trigPin, HIGH);
    delayMicroseconds(10);
    digitalWrite(trigPin, LOW);

    duration = pulseIn(echoPin, HIGH);
    distance = (duration/2) / 29.1;

    map(distance, 0, 400,200,10);
    tone(pinBuzzer,(10,262,distance));

    if (distance >= 400 || distance <= 0){
      Serial.println("Out of range");
    }
    else {
      Serial.print(distance);
      Serial.println(" cm");
    }
    delay(50);
  }