#include<SoftwareSerial.h> 

#define TX 0
#define RX 1

SoftwareSerial serial(RX,TX); 

#define echoPin 7 
#define trigPin 8 

const int ledPin = 3;

long duration; 
long distance; 

void setup() {
  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT); 
  pinMode(ledPin,OUTPUT); 

  serial.begin(9600); // // Serial Communication is starting with 9600 of baudrate speed
  serial.println("Ultrasonic Sensor HC-SR04 Test"); // print some text in Serial Monitor
  serial.println("with Arduino UNO R3");
}
void loop() {
  // Clears the trigPin condition
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  // Sets the trigPin HIGH (ACTIVE) for 10 microseconds
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  // Reads the echoPin, returns the sound wave travel time in microseconds
  duration = pulseIn(echoPin, HIGH);
  // Calculating the distance
  distance = duration * 0.034 / 2; 
  if (distance < 10)
serial.println("good");   

}