Virtual IoT Lab DEI

ARDUINO CODE
/* -----------------------------------------------------------
Objective:
Measure ambient light using an LDR and adjust LED brightness
based on the light intensity.

Components:
- LDR + 4.7 kΩ resistor (voltage divider)
- LED + 220 Ω resistor
- Arduino Uno

Working:
The LDR changes its resistance with light. A voltage divider
outputs a varying voltage to A0 (0–5V). Arduino reads this
value (0–1023) and maps it to 0–255 to control LED brightness
on pin 9 using PWM.
   ----------------------------------------------------------- */

int sensorValue = 0;  // To store analog value from LDR

const int ldrPin = A0;   // LDR output to analog pin A0
const int ledPin = 9;    // LED connected to PWM pin 9

void setup() {
  pinMode(ldrPin, INPUT);   // LDR analog input
  pinMode(ledPin, OUTPUT);  // LED output
  Serial.begin(9600);       // Initialize serial monitor
}

void loop() {
  sensorValue = analogRead(ldrPin);  // Read LDR value (0–1023)
  Serial.println(sensorValue);       // Display light intensity

  int ledValue = map(sensorValue, 0, 1023, 0, 255);  // Map to brightness
  analogWrite(ledPin, ledValue);                     // Set LED brightness

  delay(100);  // Delay for stability
}
Start Simulation
