#include <LiquidCrystal_I2C.h>
#include <Wire.h>

// for ultrasonic sensor
// A0 TO A3 for I/P and A4 and A5 for led blinking.

int trig_0 = A0;
int trig_1 = A1;
int echo_0 = A2;
int echo_1 = A3;
int led_0 = A4;
int led_1 = A5;
int dist_0, dist_1;

// for display

LiquidCrystal_I2C lcd(0x27, 16, 2);

// for relay

int relay_0 = 2;
int relay_1 = 3;

void setup() {
  // for ultrasonic sensor

  pinMode(trig_0, OUTPUT);
  pinMode(trig_1, OUTPUT);
  pinMode(echo_0, INPUT);
  pinMode(echo_1, INPUT);
  pinMode(led_0, OUTPUT);
  pinMode(led_1, OUTPUT);

  // for Display

  Serial.begin(9600);
  lcd.init();
  lcd.backlight();

  // for relay or coil

  pinMode(relay_0, OUTPUT);
  pinMode(relay_1, OUTPUT);
}

void loop() {

  // for display

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Point 1");
  lcd.setCursor(0, 1);
  lcd.print("Off");
  lcd.setCursor(8, 0);
  lcd.print("Point 2");
  lcd.setCursor(8, 1);
  lcd.print("Off");

  if (dist_0 <= 25) {
    digitalWrite(led_0, HIGH);
    lcd.setCursor(0, 1);
    lcd.print("On ");
    st0();
    digitalWrite(relay_0, HIGH);
  }

  if (dist_1 <= 25) {
    digitalWrite(led_1, HIGH);
    lcd.setCursor(8, 1);
    lcd.print("On ");
     st1();
    digitalWrite(relay_1, HIGH);
  }
}

void st0() {

  // for ultrasonic sensor init 0

  digitalWrite(trig_0, LOW);
  delayMicroseconds(2);
  digitalWrite(trig_0, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig_0, LOW);
  long duration_0 = pulseIn(echo_0, HIGH);
  dist_0 = duration_0 * 0.034 / 2;


}

void st1() {

  // for ultrasonic sensor init 1

  digitalWrite(trig_1, LOW);
  delayMicroseconds(2);
  digitalWrite(trig_1, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig_1, LOW);
  long duration_1 = pulseIn(echo_1, HIGH);
  dist_1 = duration_1 * 0.034 / 2;

}