Automatic Solar Tracker( Towards Greener Earth)

In today’s world, pollution is the main risk factor which effects every element of the nature in a real bad way. The surroundings which we see have mostly been depleted or in the verge of depletion due to pollution. One of the major reason for pollution is the power plants like thermal,nuclear etc. These kinds of power plants releases large amount of waste like ash,nuclear waste etc. These kinds of power plants give us lot of energy but in turn it pollutes the environment. So, as a remedy along with these non conventional methods, environment friendly methods are also used. One of the main producers are solar,wind and hydro power plants.

The large magnitude of solar energy makes it appealing for harnessing such an enormous energy which could be a great rise for overall global energy budget. Around 30% of the entire sun rays gets reflected back to space and most of solar panels being fixed at a particular angle may not receive adequate amount of solar energy. So, in the below schematics represent the idea of solar tracker which changes its panels position according to sun position.

In this blog, we are going to discuss about a more efficient way to increase the efficiency of the solar panels.


Solar tracker are devices which are used to orient the photovoltaic reflectors according to the position of the sun. Since, the suns’s position changes as per the time, trackers are used to align the collection system to maximize energy production. Several factors must be considered before using the tracker. The below project describes single axis solar tracker which either tacks horizontal or vertical movement of the sun path. For this project, the solar tacker taken in consideration is horizontal tracker. Entire horizontal axis i.e. 0 to 180 degree as the path for sun.

Circuit Description:

Hardware used for this above circuit is servo motor, LDR sensors, solar panel,10k resistors and arduino uno. Servo motor is used to the change the position of solar panel. LDR is used to detect the change in the suns light so as to change the position of the panel according to it. The two LDR’s are placed at the two sides of solar panel. The servo will move the solar panel towards the LDR whose resistance will be low, mean towards the LDR on which light is falling, that way it follow the light. If the resistance remains same on both sides of the panel, the panel will remain in its current position.

Above circuit diagram explains, two LDR’s are connected to Analog pins of A0 and A1. Servo pin is connected to pin 9 and has given ground and +5v. LDR’s resistance will decrease when light falls on it, based on it panel changes its position.


  • 2 10kohm resistor
  • 2 LDR
  • 1 servo motor
  • Solar panel
  • Arduino Uno
  • 9v battery


#include <Servo.h>      
Servo sg90;             //initializing a variable for servo named sg90
int initialposition = 90;  
int LDR1 = A0;          
int LDR2 = A1;        
int range = 5;          
int servopin=9;
void setup() 
  pinMode(LDR1, INPUT);  
  pinMode(LDR2, INPUT);
void loop() 
  int R1 = analogRead(LDR1);
  int R2 = analogRead(LDR2);
  int diff1= abs(R1 - R2);  
  int diff2= abs(R2 - R1);
  if((diff1 <= range) || (diff2 <= range)) {
            //if the difference is under the error then do nothing
  } else {    
    if(R1 > R2)
      initialposition = --initialposition;  //Move the servo towards 0 degree
    if(R1 < R2) 
      initialposition = ++initialposition; //Move the servo towards 180 degree

Application :

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