sketch sensore distanza per Arduino

sketch ARDUINO UNO per realizzare un sensore di distanza con modulo HC-SR04 #define TRIG_PIN 10#define ECHO_PIN 9#define sound_pin 7 void setup() {  Serial.begin(9600);pinMode(sound_pin, OUTPUT);pinMode(TRIG_PIN, OUTPUT);pinMode(ECHO_PIN, INPUT);digitalWrite(TRIG_PIN, LOW); } void loop() { digitalWrite(TRIG_PIN, HIGH);delayMicroseconds(10);digitalWrite(TRIG_PIN, LOW);int tempo = pulseIn(ECHO_PIN, HIGH);int distanza = 0.03438 * tempo /2;Serial.println (distanza);Serial.println (tempo);delay (500);}