IoT Smart Light Control with Ultrasonic Sensor Simulation

🔧 Introduction

Smart lighting is one of the most popular IoT applications. In this project, we’ll build a system where an ultrasonic sensor detects motion or proximity, and an LED light turns on automatically. We’ll demonstrate the setup using a simulation environment, making it easy for beginners to reproduce before moving to real hardware.

🛠️ Components Needed

• Arduino Uno
• HC-SR04 Ultrasonic Sensor
• LED
• 220Ω resistor
• Jumper wires

 ⚡ Wiring Overview

• Ultrasonic Sensor (HC-SR04):
• VCC → 5V
• GND → GND
• TRIG → Pin 8
• ECHO → Pin 9
• LED:

• Anode (+) → Pin 10 (through 220Ω resistor)
• Cathode (–) → GND

📸 Circuit Diagram (Simulation)

💻 Arduino Code

// IoT Smart Light Control with Ultrasonic Sensor
const int trigPin = 12;
const int echoPin = 11;
const int ledPin =  8;

long duration;
int distance;

void setup() {
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(ledPin, OUTPUT);
  Serial.begin(9600);
}

void loop() {
  // Trigger ultrasonic pulse
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  // Read echo
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  Serial.print("Distance: ");
  Serial.println(distance);

  if (distance < 20) {
    digitalWrite(ledPin, HIGH); // Turn LED ON
  } else {
    digitalWrite(ledPin, LOW);  // Turn LED OFF
  }

  delay(100);
}

🧠 How It Works

• The ultrasonic sensor measures distance using sound pulses.
• If an object is within 20 cm, the LED turns ON.
• Otherwise, the LED stays OFF.
• This simulates a smart light system that reacts to presence.

🚀 Extensions

• Replace LED with a relay + bulb for real-world lighting.
• Add WiFi (ESP8266) to control lights remotely.
• Log sensor data to a cloud platform like ThingSpeak.                                                                                                      

 📥Download Wiring Diagram PDF (Simulation) — 

 Wiring Diagram PDF