#define TRIG_PIN 23
#define ECHO_PIN 22

float duration_us, distance_cm;

void setup() {
  Serial.begin(9600);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
}

void loop() {
digitalWrite(TRIG_PIN, HIGH);
delayMicroseconds(10);
digitalWrite(TRIG_PIN, LOW);
duration_us = pulseIn(ECHO_PIN,HIGH);
distance_cm = 0.017*duration_us;
Serial.println("distance: ");
Serial.println(distance_cm);
Serial.println(" cm");
delay(500);
}