ESP32 Tutorial 5/55 - LED Fade, control brightness of an LED -ESP32 IoT Learning kit

ESP32 Tutorial 5/55 - LED Fade, control brightness of an LED -ESP32 IoT Learning kit

This tutorial demonstrates how to control the brightness of an LED using an ESP32 microcontroller, specifically the SunFounder ESP32 IoT Learning Kit (in video at 00:04). This project is ideal for beginners learning about pulse width modulation (PWM) and its applications in controlling the intensity of light sources. The ESP32's built-in PWM capabilities allow for smooth, precise control, opening up a world of possibilities for creative projects.

Practical Applications:

• Creating ambient lighting systems with adjustable brightness.
• Building a simple nightlight with gradual fading.
• Developing a dynamic indicator light for various states (e.g., low battery, network connection).
• Integrating with other sensors and actuators to create complex interactive installations.

Hardware/Components

The project utilizes the SunFounder ESP32 Starter Kit (in video at 00:12), which includes an ESP32 microcontroller, an extension board, various components, and an 18650 lithium battery. You will also need an LED and a 220-ohm resistor (in video at 04:32).

Wiring Guide

Refer to the wiring diagram in the video (in video at 01:46 and 04:18) and the detailed explanation at timestamp 04:40. The wiring involves connecting the LED's anode to the resistor, the resistor to the ESP32's GPIO 26 pin, and the LED's cathode to ground.

LED in series with a 220 ohm resistor.  Below is the wiring on breadboard. 

Code Explanation

The Arduino code uses Pulse Width Modulation (PWM) to control the LED's brightness. The key configurable parts are:

• ledPin: Defines the GPIO pin connected to the LED (in video at 09:41, set to 26). Change this if you use a different pin.
• fadeAmount: Controls the rate at which the LED's brightness changes (in video at 10:06). A higher value results in faster fading. The code automatically reverses the direction when the brightness reaches the minimum (0) or maximum (255) value (in video at 11:44).

const int ledPin = 26;  // The GPIO pin for the LED
int brightness = 0;
int fadeAmount = 5;

void setup() {
  ledcAttachPin(ledPin, 0); // Attach pin to PWM channel
}

void loop() {
  ledcWrite(ledPin, brightness); 
  brightness = brightness + fadeAmount;
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  delay(50); 
}

Live Project/Demonstration

The video demonstrates the fading LED in action (in video at 14:51). The instructor shows how to adjust the fadeAmount variable to control the speed of the fade (in video at 15:16 and 15:51). The process of uploading the code to the ESP32 is also shown (in video at 14:20).

Chapters

• [00:00] Introduction and Project Overview
• [00:12] ESP32 Starter Kit Overview
• [01:46] Wiring Diagram and Explanation
• [02:03] Digital Signals and PWM
• [04:18] Wiring the LED
• [06:33] Code Explanation: Functions
• [09:11] Code Explanation: Fading LED
• [13:33] Uploading the Code
• [14:51] Live Demonstration and Adjustments

Hình ảnh

LED_fade_ESP32

LED_with_Resistor

LED_fade_ESP32

LED_with_Resistor

const int ledPin = 26;  // The GPIO pin for the LED
int brightness = 0;
int fadeAmount = 5;

void setup() {
  ledcAttach(ledPin, 5000, 8);  // Attach the LED pin
}

void loop() {
  ledcWrite(ledPin, brightness);  // Write the new brightness value to the PWM pin
  brightness = brightness + fadeAmount;
  if (brightness <= 0 || brightness >= 255) {
    fadeAmount = -fadeAmount;
  }
  delay(50);  // Wait for 50 milliseconds
}