Программирование роботов на базе Arduino

#define echoPin = 2;
#define trigPin = 3;
#define buzzer_pin = 12;
void setup() {
  pinMode(buzzer_pin,OUTPUT);
  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);
}

void loop() {
  int duration;
  digitalWrite(trigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin,LOW);
  duration = pulseIn(echoPin,HIGH);
  int nota = map(duration, 0, 1023, 2500, 4500);
  tone(buzzer_pin,nota,100);
  delay(20);
}