LED Brightness Control Using PWM

Solving Approach:

How do you plan to solve it?

• PWM Output
  • Use analogWrite(pin, value) (0–255 duty cycle range) to control brightness.
  • The LED must be connected to a PWM-capable pin (like D3, D5, D6, D9, D10, D11 on Uno).
• Timing Calculation
  • Fade up: 2 seconds → brightness goes from 0 → 255
    • Step delay = 2000 ms / 255 ≈ 7.8 ms per increment
  • Fade down: 1 second → brightness goes from 255 → 0
    • Step delay = 1000 ms / 255 ≈ 3.9 ms per decrement
• Looping
  • Continuously run the fade-up and fade-down in the loop() function.

Code

/*Paste your code here*/
const int ledPin = 9;  // Connect LED (with resistor) to PWM pin D9

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // Fade UP: 0 → 255 in 2 seconds
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(ledPin, brightness);
    delay(2000 / 255);  // ~7.8 ms per step
  }

  // Fade DOWN: 255 → 0 in 1 second
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(ledPin, brightness);
    delay(1000 / 255);  // ~3.9 ms per step
  }
}



 

Output 

Video

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Photo of Output

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