#include "Arduino.h"
class Ultrasonic
{
    public:
    Ultrasonic(int pin);
    void DistanceMeasure(void);
    double microsecondsToCentimeters(void);
    double microsecondsToInches(void);
    private:
    int this_pin;//pin number of Arduino that is connected with SIG pin of Ultrasonic Ranger.
    long duration;// the Pulse time received;
};
Ultrasonic::Ultrasonic(int pin)
{
    this_pin = pin;
}
/*Begin the detection and get the pulse back signal*/
void Ultrasonic::DistanceMeasure(void)
{
    pinMode(this_pin, OUTPUT);
    digitalWrite(this_pin, LOW);
    delayMicroseconds(2);
    digitalWrite(this_pin, HIGH);
    delayMicroseconds(5);
    digitalWrite(this_pin,LOW);
    pinMode(this_pin,INPUT);
    duration = pulseIn(this_pin,HIGH);
}
/*The measured distance from the range 0 to 400 Centimeters*/
double Ultrasonic::microsecondsToCentimeters(void)
{
    return duration/29.0/2.0;
}
/*The measured distance from the range 0 to 157 Inches*/
double Ultrasonic::microsecondsToInches(void)
{
    return duration/74.0/2.0;
}

Ultrasonic ultrasonic(2);
void setup()
{
    Serial.begin(9600);
}
void loop()
{
    double RangeInInches;
    double RangeInCentimeters;
    ultrasonic.DistanceMeasure();// get the current signal time;
    RangeInInches = ultrasonic.microsecondsToInches();//convert the time to inches;
    RangeInCentimeters = ultrasonic.microsecondsToCentimeters();//convert the time to centimeters
    Serial.println("The distance to obstacles in front is: ");
    Serial.print(RangeInInches);//0~157 inches
    Serial.println(" inch");
    Serial.print(RangeInCentimeters);//0~400cm
    Serial.println(" cm");
    delay(1000);
}