Control LED Brightness with ESP32 PWM

Understand the target result

Use ESP32 PWM to fade an LED smoothly and understand duty cycle. The expected result is: The LED fades smoothly from off to full brightness and back.

Prepare the board and parts

Disconnect the ESP32 from USB. Put the ESP32, breadboard, jumper wires, and the listed lesson parts in front of you. Straighten bent pins gently and never force a module into the breadboard.

Make each connection with power off

1. Connect GPIO 23 to a 220Ω resistor.
2. Connect the resistor to the LED anode.
3. Connect the LED cathode to GND.

Install any library and upload the code

No additional Arduino library is required for this starter sketch. Select your ESP32 board and serial port before clicking Upload.

const int LED_PIN = 23;

void setup() {
  ledcAttach(LED_PIN, 5000, 8);
}

void loop() {
  for (int duty = 0; duty <= 255; duty++) {
    ledcWrite(LED_PIN, duty);
    delay(8);
  }
  for (int duty = 255; duty >= 0; duty--) {
    ledcWrite(LED_PIN, duty);
    delay(8);
  }
}

Power the circuit and observe

Connect USB power only after the wiring check. Open Serial Monitor at 115200 baud when the sketch prints data. Watch the circuit for at least 20 seconds and compare it with this expected behavior: The LED fades smoothly from off to full brightness and back.

Change one value and test again

Make one small change—such as a delay, threshold, brightness, or displayed message—then upload again. This confirms that you understand which part of the program controls the result.