Arduino Project

Arduino Smart Street Light with LDR and IR Sensors

Kit purchase

Looking for parts? Check out our all-in-one kits below — packed with components, beginner-friendly guides, and tons of fun.

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Name	Includes Arduino board	PURCHASE LINK
Elite Explorer Kit	Arduino Uno R4 WiFi	BUY
3 in 1 Ultimate Starter Kit	Arduino Uno R4 Minima	BUY
Ultimate Sensor Kit	Arduino Uno R4 Minima	BUY
Universal Maker Sensor Kit	×	BUY

Course Introduction

This Arduino project builds a smart street light system using an LDR, three IR sensors, and three LEDs with the Arduino UNO R4 WiFi.

During the day, the LEDs remain off. At night, the IR sensors detect nearby objects and automatically turn on the corresponding LEDs.

This system demonstrates how light and object detection can be combined to create an energy-efficient smart street lighting system.

Note

If this is your first time working with an Arduino project, we recommend downloading and reviewing the basic materials first.

1.1 Install Arduino IDE(Important)
1.2 Introduction of Arduino IDE

Required Components

In this project, we need the following components:

SN	COMPONENT INTRODUCTION	QUANTITY	PURCHASE LINK
1	Arduino UNO R4 Minima	1	BUY
2	USB Type-C cable	1	×
3	Breadboard	1	BUY
4	Wires	Several	BUY
5	LED	3	BUY
6	Photoresistor	1	BUY
7	IR Obstacle Avoidance Sensor Module	3	BUY
8	Resistor(220Ω/10kΩ)	Several	BUY

Wiring

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Common Connections:

IR Obstacle Avoidance Senso Module 1
OUT: Connect to 2 on the Arduino. GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.

IR Obstacle Avoidance Sensor Module 2
OUT: Connect to 3 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.

IR Obstacle Avoidance Sensor Module 3
OUT: Connect to 4 on the Arduino.
GND: Connect to breadboard’s negative power bus.
VCC: Connect to breadboard’s red power bus.

LED 1
Connect the LED anode to a 220Ω resistor then to 8 on the Arduino, and the cathode to the negative power bus on the breadboard.

LED 2
Connect the LED anode to a 220Ω resistor then to 9 on the Arduino, and the cathode to the negative power bus on the breadboard.

LED 3
Connect the LED anode to a 220Ω resistor then to 10 on the Arduino, and the cathode to the negative power bus on the breadboard.

Photoresistor
Connect to a 10kΩ resistor then to A0 on the Arduino.
Connect to breadboard’s red power bus.
10kΩ resistor to breadboard’s negative power bus.

Writing the Code

Note
You can copy this code into Arduino IDE.
Don’t forget to select the board(Arduino UNO R4 Minima/WIFI) and the correct port before clicking the Upload button.

// =====================================================
// Smart Street Light
// Arduino UNO R4 WiFi
// LDR + 3 IR Sensors + 3 LEDs
// =====================================================

// LDR voltage divider
const int ldrPin = A0;

// IR sensor pins
const int ir1Pin = 2;
const int ir2Pin = 3;
const int ir3Pin = 4;

// LED pins
const int led1Pin = 8;
const int led2Pin = 9;
const int led3Pin = 10;

// =====================================================
// Light threshold
// UNO R4 uses 14-bit ADC by default on analogRead()
// typical range: 0 - 16383
// Adjust this value after checking Serial Monitor
// =====================================================
const int DARK_THRESHOLD = 700;

void setup() {
  Serial.begin(9600);

  pinMode(ir1Pin, INPUT);
  pinMode(ir2Pin, INPUT);
  pinMode(ir3Pin, INPUT);

  pinMode(led1Pin, OUTPUT);
  pinMode(led2Pin, OUTPUT);
  pinMode(led3Pin, OUTPUT);

  digitalWrite(led1Pin, LOW);
  digitalWrite(led2Pin, LOW);
  digitalWrite(led3Pin, LOW);
}

void loop() {

  // Read ambient light
  int lightValue = analogRead(ldrPin);

  Serial.print("Light Value: ");
  Serial.println(lightValue);

  // ===================================================
  // Night mode
  // ===================================================
  if (lightValue < DARK_THRESHOLD) {

    int ir1State = digitalRead(ir1Pin);
    int ir2State = digitalRead(ir2Pin);
    int ir3State = digitalRead(ir3Pin);

    // Most IR obstacle sensors output LOW
    // when an object is detected

    digitalWrite(
      led1Pin,
      ir1State == LOW ? HIGH : LOW
    );

    digitalWrite(
      led2Pin,
      ir2State == LOW ? HIGH : LOW
    );

    digitalWrite(
      led3Pin,
      ir3State == LOW ? HIGH : LOW
    );
  }

  // ===================================================
  // Day mode
  // ===================================================
  else {

    digitalWrite(led1Pin, LOW);
    digitalWrite(led2Pin, LOW);
    digitalWrite(led3Pin, LOW);
  }

  delay(50);
}

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Arduino Project

Arduino Smart Street Light with LDR and IR Sensors

Kit purchase

Course Introduction

Required Components

Wiring

Common Connections:

Writing the Code

Arduino Project

Arduino Smart Street Light with LDR and IR Sensors

Kit purchase

Course Introduction

Required Components

Wiring

Common Connections:

Writing the Code

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