Single axis solar tracker project tutorial

Single axis solar tracker project tutorial

Introduction to Single‑Axis Solar Tracking

A single‑axis solar tracker is a system designed to follow the sun’s path along a single plane (east–west), optimizing the panel's exposure to sunlight and increasing energy output. highlights that this is a popular Arduino-based project, allowing hobbyists to enhance solar harvesting efficiency by manually adjusting panel direction throughout the day

Tracker Types: Single vs Dual Axis

Single‑axis: Moves on one motor (one axis), typically tracking east to west across the sky.

• Single‑axis: Moves on one motor (one axis), typically tracking east to west across the sky.

Dual‑axis: Tracks both east–west and north–south movement, offering more precision but increased complexity. The tutorial focuses on the simpler, more accessible single‑axis setup

Dual‑axis: Tracks both east–west and north–south movement, offering more precision but increased complexity. The tutorial focuses on the simpler, more accessible single‑axis setup

How It Works – Core Concept

The design uses:

Two LDRs (Light‑Dependent Resistors),

• Two LDRs (Light‑Dependent Resistors),

An Arduino Uno, and

• An Arduino Uno, and

A servo motor mounted between +60° and −60° from a neutral position.

• A servo motor mounted between +60° and −60° from a neutral position.

The LDR pair (placed on opposite sides of the panel) measures light intensity. When one LDR reads a higher value, the Arduino interprets the difference and commands the servo to rotate toward the brighter one. This ensures the panel consistently aligns with maximum solar intensity

Benefits of Tracking

Since solar cell output is directly proportional to light intensity, fine-tuning panel orientation maximizes energy conversion. Traditional fixed panels may lose a large portion of available light, particularly during early and late sunlight hours. By contrast, a single‑axis tracker recaptures much of this lost energy by keeping the panel aimed at the sun

Component Overview

Required hardware and software:

Arduino Uno

• Arduino Uno

2 × LDR sensors (~5 MΩ)

• 2 × LDR sensors (~5 MΩ)

2 × 10 KΩ resistors

• 2 × 10 KΩ resistors

1 × SG‑90 micro‑servo motor

• 1 × SG‑90 micro‑servo motor

Solar panel, jumper wires, and breadboard

• Solar panel, jumper wires, and breadboard

Arduino IDE for programming

• Arduino IDE for programming

A PCB (optional) can help tidy up construction, and the author mentions using PCBWAY for fabrication

Circuit Diagram

The Fritzing-based wiring diagram illustrates:

LDRs connected in voltage dividers to analog pins A0 and A1,

• LDRs connected in voltage dividers to analog pins A0 and A1,

Servo attached to a PWM-capable pin (D9),

• Servo attached to a PWM-capable pin (D9),

Arduino powers and interprets the sensors,

• Arduino powers and interprets the sensors,

The servo rotates the panel accordingly.

• The servo rotates the panel accordingly.

This clear visual guide enables makers to confidently replicate the setup

Arduino Code Explanation

The provided sketch (below) outlines core logic:

cpp

CopyEdit

#include <Servo.h>
Servo sg90;
int LDR1 = A0, LDR2 = A1, servopin = 9;
int initial_position = 90, error = 5;

void setup() {
sg90.attach(servopin);
pinMode(LDR1, INPUT);
pinMode(LDR2, INPUT);
sg90.write(initial_position);
delay(2000);
}

void loop() {
int R1 = analogRead(LDR1), R2 = analogRead(LDR2);
if (abs(R1 - R2) > error) {
if (R1 > R2) initial_position--;
else initial_position++;
sg90.write(initial_position);
}
delay(100);
}

cpp

CopyEdit
#include <Servo.h>
Servo sg90;
int LDR1 = A0, LDR2 = A1, servopin = 9;
int initial_position = 90, error = 5;

void setup() {
  sg90.attach(servopin);
  pinMode(LDR1, INPUT);
  pinMode(LDR2, INPUT);
  sg90.write(initial_position);
  delay(2000);
}

void loop() {
  int R1 = analogRead(LDR1), R2 = analogRead(LDR2);
  if (abs(R1 - R2) > error) {
    if (R1 > R2) initial_position--;
    else initial_position++;
    sg90.write(initial_position);
  }
  delay(100);
}

Servo initialization: Starts at 90° (center).

• Servo initialization: Starts at 90° (center).

Read sensors: Measures both LDR values.

• Read sensors: Measures both LDR values.

Threshold check: Moves the servo only when the difference exceeds a set error margin.

• Threshold check: Moves the servo only when the difference exceeds a set error margin.

Position adjustment: Decrements or increments servo angle based on which LDR is brighter.

• Position adjustment: Decrements or increments servo angle based on which LDR is brighter.

Fine control: Small 1° steps smoothen tracking

Fine control: Small 1° steps smoothen tracking

Practical Considerations and Tips

Tracking Range: ±60° is used here, but can be adjusted depending on installation.

• Tracking Range: ±60° is used here, but can be adjusted depending on installation.

Tolerance Setting: The error threshold avoids jittery movement when light levels are similar.

• Tolerance Setting: The error threshold avoids jittery movement when light levels are similar.

Servo Limits: Keep angle values between 0–180° to protect the servo.

• Servo Limits: Keep angle values between 0–180° to protect the servo.

PCB Usage: A custom board improves wiring neatness, though a breadboard works for prototypes.

• PCB Usage: A custom board improves wiring neatness, though a breadboard works for prototypes.

Servo Response: Step size (initial_position ±1) and delay can be tuned for responsiveness vs stability.

• Servo Response: Step size (initial_position ±1) and delay can be tuned for responsiveness vs stability.

Conclusion

This Techatronic tutorial offers an excellent introduction to solar tracking using Arduino. It balances simplicity and functionality—making it ideal for hobbyists, students, or anyone interested in renewable energy projects. By leveraging inexpensive sensors, a microcontroller, and a servo, you can drastically improve solar panel efficiency throughout the day, typically boosting energy capture beyond fixed installations