DIY dual axis solar tracker #SustainableEveryDay

DIY dual axis solar tracker

Arduino Solar Tracker Dual Axis

In modern solar tracking systems, the solar panels are fixed on a structure that moves according to the position of the sun.

Let us design a solar tracker using two servo motors, a light sensor consisting of four LDRs and Arduino UNO board.

Circuit Diagram

The circuit design of solar tracker is simple but setting up the system must be done carefully.

Four LDRs and Four 100KΩ resistors are connected in a voltage divider fashion and the output is given to 4 Analog input pins of Arduino.

The PWM inputs of two servos are given from digital pins 9 and 10 of Arduino.

Components Required

• Arduino UNO  - https://amzn.to/2RguMc4
• Servo Motor - https://amzn.to/32ZvFZv
• LDR - https://amzn.to/3nLzP0J
• Resistors - https://amzn.to/3e5Bbjt

Working

LDRs are used as the main light sensors. Two servo motors are fixed to the structure that holds the solar panel. The program for Arduino is uploaded to the microcontroller. The working of the project is as follows.

LDRs sense the amount of sunlight falling on them. Four LDRs are divided into top, bottom, left and right.

For east – west tracking, the analog values from two top LDRs and two bottom LDRs are compared and if the top set of LDRs receive more light, the vertical servo will move in that direction.

If the bottom LDRs receive more light, the servo moves in that direction.

For angular deflection of the solar panel, the analog values from two left LDRs and two right LDRs are compared. If the left set of LDRs receive more light than the right set, the horizontal servo will move in that direction.

If the right set of LDRs receive more light, the servo moves in that direction.

Project Code

	#include <Servo.h>
	//defining Servos
	Servo servohori;
	int servoh = 0;
	int servohLimitHigh = 160;
	int servohLimitLow = 20;
	Servo servoverti;
	int servov = 0;
	int servovLimitHigh = 160;
	int servovLimitLow = 20;
	//Assigning LDRs
	int ldrtopl = 2; //top left LDR green
	int ldrtopr = 1; //top right LDR yellow
	int ldrbotl = 3; // bottom left LDR blue
	int ldrbotr = 0; // bottom right LDR orange
	void setup ()
	{
	servohori.attach(10);
	servohori.write(0);
	servoverti.attach(9);
	servoverti.write(0);
	delay(500);
	}
	void loop()
	{
	servoh = servohori.read();
	servov = servoverti.read();
	//capturing analog values of each LDR
	int topl = analogRead(ldrtopl);
	int topr = analogRead(ldrtopr);
	int botl = analogRead(ldrbotl);
	int botr = analogRead(ldrbotr);
	// calculating average
	int avgtop = (topl + topr) / 2; //average of top LDRs
	int avgbot = (botl + botr) / 2; //average of bottom LDRs
	int avgleft = (topl + botl) / 2; //average of left LDRs
	int avgright = (topr + botr) / 2; //average of right LDRs
	if (avgtop < avgbot)
	{
	servoverti.write(servov +1);
	if (servov > servovLimitHigh)
	{
	servov = servovLimitHigh;
	}
	delay(10);
	}
	else if (avgbot < avgtop)
	{
	servoverti.write(servov -1);
	if (servov < servovLimitLow)
	{
	servov = servovLimitLow;
	}
	delay(10);
	}
	else
	{
	servoverti.write(servov);
	}
	if (avgleft > avgright)
	{
	servohori.write(servoh +1);
	if (servoh > servohLimitHigh)
	{
	servoh = servohLimitHigh;
	}
	delay(10);
	}
	else if (avgright > avgleft)
	{
	servohori.write(servoh -1);
	if (servoh < servohLimitLow)
	{
	servoh = servohLimitLow;
	}
	delay(10);
	}
	else
	{
	servohori.write(servoh);
	}
	delay(50);
	}