//HC RS04 Sensore ultrasuoni
const int triggerPort = 9;
const int echoPort = 10;
const int led = 3;
 
void setup() {
 
pinMode(triggerPort, OUTPUT);
pinMode(echoPort, INPUT);
pinMode(led, OUTPUT);
Serial.begin(9600);
}
 
void loop() {
 

digitalWrite( triggerPort, LOW );
//invia un impulso di 10microsec su trigger
digitalWrite( triggerPort, HIGH );
delayMicroseconds( 10 );
digitalWrite( triggerPort, LOW );
 
long durata = pulseIn( echoPort, HIGH );
 
long distanza = 0.034 * durata / 2;
 
Serial.print("distanza: ");
 
//durata in millisecondi
if( durata > 38000 ){
Serial.println("Fuori portata   ");
}
else{ 
Serial.print(distanza); 
Serial.println(" cm");
int fadeValue = map(durata, 0, 38000, 0, 255)
analogWrite(led, fadeValue);
}

delay(1000);
}