// Include NewPing Library
#include "NewPing.h"

// Hook up HC-SR04 with Trig to Arduino Pin 9, Echo to Arduino pin 10
#define TRIGGER_PIN 9
#define ECHO_PIN 10
const int RELAY_PIN = 3; 
// Maximum distance we want to ping for (in centimeters).
#define MAX_DISTANCE 400	

// NewPing setup of pins and maximum distance.
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE);

void setup() {
	pinMode(RELAY_PIN, OUTPUT);
	Serial.begin(9600);
}

void loop() {
	int length=sonar.ping_cm();
	Serial.print("Distance = ");
	Serial.print(length);
	Serial.println(" cm");
	delay(500);

	if(length<60){
		digitalWrite(RELAY_PIN, HIGH);
		delay(500);
	}
	else{
		digitalWrite(RELAY_PIN, LOW);
	}
	
}