Solar Circuit Diagrams

Sun Tracking Solar Panel

In this project, we will see a simple Sun Tracking Solar Panel circuit which will track the Sun and position the solar panels accordingly.


  • Introduction
  • Principle of Sun Tracking Solar Panel
  • Sun Tracking Solar Panel Circuit Diagram
    • Components in the Circuit
  • Automated Sun Tracking Solar Panel Circuit Design
    • ATmega328 Microcontroller
    • Solar Panel
    • LDR
    • Servo Motor
  • Code
  • How Sun Tracking Solar Panel Works?
  • Advantages of Sun Tracking Solar Panel
  • Sun Tracking Solar Panel Applications
  • Limitations of Sun Tracking Solar Panel Circuit

As nonrenewable energy supplies become scarcer, renewable energy sources are increasingly used to generate electricity. Solar panels are getting increasingly popular. We’ve already read an article on how to set up solar panels at home. A solar panel gathers solar energy, converts it to electrical energy, and then stores it in a battery.

This energy can be used as needed or as a straight replacement for grid-supplied electricity. The applications that make use of the energy stored in batteries are listed below.

Because of the Earth’s rotation, the Sun’s location in relation to the solar panel is not fixed. Solar panels should absorb as much energy as possible in order to make the most efficient use of solar energy.

This is only possible if the panels are always pointing in the direction of the Sun. As a result, the solar panel should revolve towards the direction of the Sun at all times. The circuit that rotates a solar panel is described in this article.

Sun Tracking Solar Panel

Principle of Sun Tracking Solar Panel

Two LDRs, a solar panel, a servo motor, and an ATmega328 Microcontroller make up the Sun tracking solar panel.

On the solar panel’s edges, two light-dependent resistors are positioned. When light falls on a light dependent resistor, it produces a low resistance. The panel is rotated in the direction of the Sun by a servo motor connected to it. The panel is set up in such a way that the light from two LDRs is compared, and the panel is rotated towards the LDR with the highest intensity, i.e. the least resistance. The panel is rotated at a specific angle using a servo motor.

When the intensity of the light falling on right LDR is more, panel slowly moves towards right and if intensity on the left LDR is more, panel slowly moves towards left. In the noon time, Sun is ahead and intensity of light on both the panels is same. In such cases, panel is constant and there is no rotation.

Sun Tracking Solar Panel Circuit Diagram

Components in the Circuit

  • Solar panel
  • ATmega328 Micro Controller
  • Light Dependent Resistor (LDR) x 2
  • 10KΩ x 3
  • Servo Motor
  • 16MHz Crystal
  • 22pF Ceramic Capacitors x 2
  • Push Button
  • Breadboard
  • Cardboard
  • Connecting Wires

Automated Sun Tracking Solar Panel Circuit Design

The proposed system consists of ATmega328 micro controller, Solar panel, Light Dependent resistors and Servo Motor.

ATmega328 Microcontroller

The ATmega328 is a microcontroller from the AVR family. It’s built on a cutting-edge RISC architecture. It’s a controller with an 8-bit resolution. There are 32K bytes of Programmable Flash memory, 1K bytes of EEPROM, and 2K bytes of SRAM in this device. There are 23 programmable I/O pins on this board. Two 8-bit timers, one 16-bit timer, 6 channel ADC with 10-bit precision, programmable USART, Serial Peripheral Interface, 2 wire serial interface (I2C), and other peripheral functions are supported.

Solar Panel

Solar panel is placed on a piece of cardboard (just for demonstration) and the bottom of the cardboard is connected to Servo motor. Solar panel consists of photovoltaic cells arranged in an order. Photovoltaic cell is nothing but a solar cell. Solar cell is made up of semiconductor material silicon.

When a light ray from Sun is incident on the solar cell, some amount of energy is absorbed by this material. The absorbed energy is enough for the electrons to jump from one orbit to other inside the atom. Cells have one or more electric field that directs the electrons which creates current. By placing metal contact energy can be obtained from these cells.


LDRs (Light Dependent Resistors) are resistors whose resistance levels are proportional to the intensity of the light. The resistance value falls as the intensity of light falling on the LDR increases. LDR has the most resistance in the dark. The LDR will produce an analogue value that must be converted to a digital value. This can be accomplished with the help of an analogue to digital converter.

Internally, the ATmega328 features an analogue to digital converter. ADC0 to ADC5 (Pins 23–28) are the six ADC channels. Individual 10K resistors are used to connect the two LDRs to ADC pins 27 and 28 in a voltage divider arrangement. The sequential approximation approach is used to convert ADC.

Servo Motor

The panel is rotated by a servo motor. A PWM signal must be sent to the servo motor’s control pin in order to operate it, therefore Pin 17 (which has PWM) is linked to the servo motor’s control pin.

You may store the energy created by the solar cells by attaching a battery to the solar panel, and then use it when needed. Separate charge controller circuits are dedicated to efficiently controlling and charging the charge obtained from solar panels.


In a previous tutorial, I have shown you “How to Burn Bootloader to ATmega328”. In this tutorial, you can understand how to upload code to the ATmega328 Microcontroller using Arduino IDE.

#include <Servo.h>
Servo myservo;
int ldr1 = 4;
int ldr2 = 5;
int val1;
int val2;
int pos=90;
void setup()
void loop()
val1 = analogRead(ldr1);
val2 = analogRead(ldr2);
val1 = map(val1, 0, 1023, 0, 180);
val2 = map(val2, 0, 1023, 0, 180);
if(val1 > (val2+50))
else if(val2 > (val1+50))

How Sun Tracking Solar Panel Works?

  1. Assemble the circuit as described and upload the code to ATmega328 Microcontroller.
  2. Power on the circuit and place the set up directly under the Sun (on the rooftop).
  3. Based on the light falling on the two LDRs, the ATmega328 Microcontroller changes the position of the Servo Motor which in turn moves in the panel.

Advantages of Sun Tracking Solar Panel

  1. The solar energy can be reused as it is non-renewable resource.
  2. This also saves money as there is no need to pay for energy used (excluding the initial setup cost)
  3. Helps in maximizing the solar energy absorption by continuously tracking the sun.

Sun Tracking Solar Panel Applications

  1. These panels can be used to power the traffic lights and streetlights
  2. These can be used in home to power the appliances using solar power.
  3. These can be used in industries as more energy can be saved by rotating the panel.

Limitations of Sun Tracking Solar Panel Circuit

  1. Though solar energy can be utilized to maximum extent this may create problems in rainy season.
  2. Although solar energy can be saved to batteries, they are heavy and occupy more space and required to change time to time.
  3. They are expensive.

So far, you’ve learned about the operation of a sun-tracking solar panel. If you want to set them up or install them on your house or office rooftops, we recommend the Best Solar Panel Kits for Homes in 2018.

This article will assist you in comprehending the concept of solar panel kits and will instruct you on how to select solar panels (important considerations) when shopping online. Read the entire article and select the one that best meets your needs.


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