#include <SoftwareSerial.h>
#define rxPin 0
#define txPin 1
#define trigPin 6
#define echoPin 5

SoftwareSerial serial(rxPin, txPin);

void setup() { //
  serial.begin (9600);
  pinMode(rxPin, INPUT);
  pinMode(txPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
}

void loop() {
  long duration, distance;
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  duration = pulseIn(echoPin, HIGH);
  distance = (duration/2) / 29.1;

  if (distance >= 400 || distance <= 0){
    serial.println("Out of range");
  }
  else {
    serial.print(distance); 
    serial.println(" cm");
  }
  delay(500);
} /* */