//biaxial solar tracking system using 
//arduino uno microcontroler
#include <Servo.h>       
#include <LiquidCrystal.h>
const int rs = 7;    
const int en = 6;   
const int d4 = 12;
const int d5 = 10;
const int d6 = 9;   
const int d7 = 8;   
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

Servo sg90;             //initializing a variable for servo named sg90

int initial_position = 90;   //Declaring the initial position at 90

int LDR1 = A0;          

int LDR2 = A1;          

int error = 5;          

int servopin=9;

void setup() 

{ 


  sg90.attach(servopin);  // attaches the servo on pin 9

  pinMode(LDR1, INPUT);   

  pinMode(LDR2, INPUT);

  sg90.write(initial_position);   //Move servo at 90 degree

  lcd.begin(16, 2);

  lcd.print("DIRECTION CHANGE");

  delay(2000);            

  

}  

 

void loop() 

{ 

  int R1 = analogRead(LDR1); 

  int R2 = analogRead(LDR2); 

  int diff1= abs(R1 - R2);   // Calculating the difference between the LDR's

  int diff2= abs(R2 - R1);

  

  if((diff1 <= error) || (diff2 <= error)) {

    //if the difference is under the error then do nothing

  } else {    

    if(R1 > R2)

    {

      initial_position = --initial_position;  //Move the servo towards 0 degree

    }

    if(R1 < R2) 

    {

      initial_position = ++initial_position; //Move the servo towards 180 degree

    }

  }

  sg90.write(initial_position); 

  lcd.setCursor(0, 1);
  lcd.print("intensity  ");
  lcd.print(millis() / 1000);

  delay(100);

}