/*
* Ultrasonic Sensor HC-SR04 and Arduino Tutorial
*
* by Dejan Nedelkovski,
* www.HowToMechatronics.com
*modified by eidha alrashdi for Fabacademy2018
*29/5/2018
*The programme is to Turn ON LED when the distance less than 20cm and flash when its above 20cm.
*/



#include<SoftwareSerial.h>
SoftwareSerial myserial (0,1); 
// defines pins numbers
const int trigPin = 3;
const int echoPin = 2;
int led=5;
// defines variables
long duration;
int distance;
void setup() {
pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT); // Sets the echoPin as an Input
pinMode(led, INPUT);
myserial.begin(9600); // Starts the serial communication
}
void loop() {
// Clears the trigPin
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
// Sets the trigPin on HIGH state for 10 micro seconds
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;
// Prints the distance on the Serial Monitor
myserial.print("Distance: ");
myserial.println(distance);

if (distance<= 15)
{
digitalWrite(led, HIGH);
delay(50);
  
}
else {
  digitalWrite(led,HIGH);
  delay(100);
  digitalWrite(led,LOW);
delay(100);
}
}