🌞 DIY Arduino Solar Tracker with Motor Control – Complete Guide

 

🌞 DIY Arduino Solar Tracker with Motor Control – Complete Guide

🔧 Overview:

This project uses Light Dependent Resistors (LDRs) to track the sun's position and adjust the orientation of a solar panel using two servo motors. Additionally, based on the sunlight intensity, it controls a motor using two buttons – ideal for automating a solar-powered device like a water pump.

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🧰 Components Required:

Component	Quantity	Description
Arduino Uno	1	Microcontroller board
Servo Motor (SG90/MG90)	2	For horizontal and vertical rotation
LDR (Light Sensor)	5	For detecting sunlight intensity and direction
10kΩ Resistors	5	Pull-down resistors for each LDR
Push Buttons	2	For controlling motor direction
DC Motor	1	Can be used for pumping or rotation purposes
NPN Transistor (optional)	1	For driving higher power motors
Diode (1N4007)	1	For back EMF protection
Power Supply (9V/12V)	1	To power the motor
Breadboard + Jumper Wires	As needed	For circuit connections

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🔌 Pin Configuration:

Arduino Pin	Connected Component
A1	LDR Top Left
A2	LDR Top Right
A3	LDR Bottom Left
A4	LDR Bottom Right
A5	LDR Middle Top (Sunlight Detection)
D5	Horizontal Servo Signal
D6	Vertical Servo Signal
D7	Motor Control A
D8	Motor Control B
D9	Button 1 (Forward)
D10	Button 2 (Reverse)
GND	All GND connections
5V	Power supply for LDRs and buttons

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⚙️ How It Works:

• LDRs detect light intensity. The 4 corner LDRs determine the direction of sunlight, and the middle LDR checks whether there is enough light.

• The Arduino calculates the average light values and adjusts the horizontal and vertical servo angles accordingly.

• If sunlight is detected and button 1 is pressed, the motor rotates in one direction.

• If no sunlight is present and button 2 is pressed, the motor rotates in the opposite direction.

• If neither condition is met, the motor stops.

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🖼️ Circuit Diagram:

📟 Arduino Code:

#include <Servo.h>

Servo horizontal; // horizontal servo

Servo vertical; // vertical servo
// LDR analog pins
const int button1 = 9;
int pos = 0;
void setup() {
  pinMode(motorA, OUTPUT);
  delay(2500); // Give servos time to initialize
void loop() {
    int lt = analogRead(ldrlt);
    int avt = (lt + rt) / 2;
    if (abs(dvert) > tol) {
    if (abs(dhoriz) > tol) {
    delay(dtime);
    for (pos = oldvalue; pos <= 180; pos++) {
    buttonStateB = digitalRead(button2);

int servoh = 180;

int servohLimitHigh = 175;

int servohLimitLow = 5;

int servov = 0;

int servovLimitHigh = 60;

int servovLimitLow = 0;

int ldrlt = A1; // Top Left

int ldrrt = A2; // Top Right

int ldrld = A3; // Bottom Left

int ldrrd = A4; // Bottom Right

int ldrmt = A5; // Middle Top LDR

const int button2 = 10;

const int motorA = 7;

const int motorB = 8;

int buttonStateA = 0;

int buttonStateB = 0;

int pos2 = 0;

int oldvalue, oldvalue2;

  horizontal.attach(5);

  vertical.attach(6);

  horizontal.write(180);

  vertical.write(0);

  pinMode(motorB, OUTPUT);

  pinMode(button1, INPUT);

  pinMode(button2, INPUT);

}

  int ldrStatus = analogRead(ldrmt);

  

  if (ldrStatus > 30) {

    buttonStateA = digitalRead(button1);

    if (buttonStateA == LOW) {

      digitalWrite(motorA, HIGH);

      digitalWrite(motorB, LOW); // Motor rotates in one direction

    } else {

      digitalWrite(motorA, LOW);

      digitalWrite(motorB, LOW); // Stop motor

    }

    int rt = analogRead(ldrrt);

    int ld = analogRead(ldrld);

    int rd = analogRead(ldrrd);

    int dtime = 10;

    int tol = 90;

    int avd = (ld + rd) / 2;

    int avl = (lt + ld) / 2;

    int avr = (rt + rd) / 2;

    int dvert = avt - avd;

    int dhoriz = avl - avr;

      if (avt > avd) {

        servov++;

        if (servov > servovLimitHigh) servov = servovLimitHigh;

      } else {

        servov--;

        if (servov < servovLimitLow) servov = servovLimitLow;

      }

      vertical.write(servov);

    }

      if (avl > avr) {

        servoh--;

        if (servoh < servohLimitLow) servoh = servohLimitLow;

      } else {

        servoh++;

        if (servoh > servohLimitHigh) servoh = servohLimitHigh;

      }

      horizontal.write(servoh);

    }

  }

  else {

    oldvalue = horizontal.read();

    oldvalue2 = vertical.read();

      horizontal.write(pos);

      delay(15);

    }

    for (pos2 = oldvalue2; pos2 >= 0; pos2--) {

      vertical.write(pos2);

      delay(15);

    }

    if (buttonStateB == LOW) {

      digitalWrite(motorA, LOW);

      digitalWrite(motorB, HIGH); // Reverse motor

    } else {

      digitalWrite(motorA, LOW);

      digitalWrite(motorB, LOW);

    }

  }

}

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