1 /* Ultrasonic rilevatore distanza
3 Rilevatore distanza minore di 5cm.
6 HC-SR04 Ping distance sensor
7 VCC to arduino 5v - GND to arduino GND
16 long duration, distance;
20 pinMode(trig, OUTPUT);
31 digitalWrite(led,HIGH);
33 digitalWrite(led,LOW);
43 digitalWrite(trig, LOW); // Prepare for ping
44 delayMicroseconds(2); //
45 digitalWrite(trig, HIGH); // Send a ping
46 delayMicroseconds(10); //
47 digitalWrite(trig, LOW); // Set down ping
48 duration = pulseIn(echo, HIGH);
49 distance = (duration/2) / 29.1; // Speed is ~300m/s,
50 // so it takes ~29.1 milliseconds for a cm.
51 // Distance is half of (out + back)
52 if (distance < 5) { // This is where the LED On/Off happens