Powerful LED Strip Patterns | Learn C++ Overloading with ESP32


Introduction

Learn how to create professional LED strip patterns using C++ and ESP-IDF framework. This guide demonstrates how to leverage C++ function overloading for clean, efficient LED control while utilizing the full power of ESP-IDF.
LED Strip

Development Environment Setup

1. Install Visual Studio Code from the official website.
2. Install the ESP-IDF plugin.

Setting Up Your ESP32 for LED Strip Projects

1. In VS Code, press Ctrl (Cmd) + Shift + P, and enter ESP-IDF: New Project.

2. Choose a template project (e.g., blink example), set the project name (e.g., my_project), and choose a storage path.

3. The system will generate a new ESP-IDF project with a basic CMake file and example code.

Project File Structure

my_project/
├── CMakeLists.txt # Build configuration
├── main/
│ ├── CMakeLists.txt # Main component's CMake configuration
│ └── main.cpp # LED Strip class and application logic
└── sdkconfig # Project configuration

Getting Started with Function Overloading

Inheritance is a key feature of OOP that allows classes to derive properties and methods from other classes. By implementing a base class that encapsulates common functionality, we can reduce code duplication and simplify complex, multi-task systems. When applied to FreeRTOS on the ESP32, inheritance allows us to create versatile task classes that streamline the process of creating, managing, and reusing multiple tasks.

Set Up the LED Strip Class

The LEDStrip class will contain functions to initialize the strip and apply various lighting patterns, such as a solid color, color wave, and blinking effect.

Complete main.cpp Code for LED Patterns

This code will initialize the ESP32, set up a simple LEDStrip class, and implement three LED patterns: solid color, color wave, and blinking—all in one file.

Explanation of Code

1. LED Strip Class Setup:
- The LEDStrip class is defined within main.cpp. It has a constructor to initialize the GPIO pin and three different setPattern functions for solid color, color wave, and blinking patterns.

2. Patterns Implementation:
- Each pattern method uses esp_log to print useful information:
- ESP_LOGI logs information about the pattern being applied (e.g., color, delay).
- ESP_LOGD provides detailed debug logs, such as the state of each LED during a wave or blink effect.

3. Logging in app_main:
- Each pattern call in app_main is preceded by a logging statement, providing context on which pattern is being executed.

4. Log Levels:
- esp_log_level_set controls log levels. Here, "LEDStrip" is set to ESP_LOG_DEBUG to get detailed logging only for the LED operations, while other logs remain at ESP_LOG_INFO.

Compiling and Flashing

In the VSCode window, find the ESP32-IDF : Build, Flash and Monitor icon to compile and flash the program.

Program Output

Once the program runs, you should see the following output in the terminal:

Conclusion

With this simplified code structure, beginners can now create complex LED Strip patterns using a single main.cpp file. This example also introduces the powerful esp_log logging system, helping track and debug each LED pattern step-by-step.

This method is ideal for learning, as you can quickly see how different patterns behave and experiment by adjusting parameters directly in one place. Happy experimenting!