ESP32 WiFi AC Remote Controller

A robust embedded systems project that transforms an ESP32 into a smart, web-controlled remote for my Electra air conditioning unit. This project showcases skills in reverse engineering, real-time operating systems (FreeRTOS), and full-stack embedded development, from hardware interfacing to a user-facing web server.

✨ Key Features

🌐 Web-Based Control: A sleek, mobile-friendly web interface to turn the AC on or off from any device on the local network.
RTOS-Powered: Leverages the FreeRTOS real-time operating system for efficient, concurrent task management.
⚙️ Multi-Core Processing: Intelligently separates tasks between the ESP32’s dual cores—Core 0 handles Wi-Fi and the web server, while Core 1 is dedicated to precise, real-time IR signal generation.
🔧 Reverse Engineered: The AC remote’s proprietary IR signal was captured, decoded, and reverse-engineered using an oscilloscope.
🛡️ Robust Synchronization: Employs binary semaphores to ensure safe and reliable communication between the web server task and the IR transmission task.
🔌 Custom Hardware: Housed in a custom-designed 3D printed enclosure for a clean and professional finish.

🛠️ Hardware

Microcontroller: ESP32-WROOM-32
Transmitter: 5mm 940nm IR LED
Resistor: Preferably 100-200 Ohm resistor. (Closer to 100 produces stronger signal)
Power: 5V USB-C Power Supply
Enclosure: Custom 3D Printed Case

📦 3D Printed Enclosure

The custom-designed enclosure provides a compact and durable housing for the electronics.

3D printed case.

🏗️ System Design

The software architecture is designed for stability and real-time performance, leveraging the power of FreeRTOS and the ESP32’s dual-core capabilities.

Task Management with FreeRTOS

The application is divided into two primary tasks:

Web Server & Wi-Fi Task (Core 0): This task is responsible for:
- Initializing and maintaining the Wi-Fi connection.
- Running the HTTP web server to serve the HTML control page.
- Listening for incoming /toggle GET requests from the user’s browser.
- Upon receiving a request, it gives a binary semaphore to signal the IR task.
IR Transmission Task (Core 1): This task is pinned to Core 1 to guarantee its execution is not preempted by the higher-priority Wi-Fi stack running on Core 0. Its responsibilities are:
- Waiting indefinitely to take the binary semaphore.
- Once the semaphore is received, it executes the ac_power_code() function to generate the precise sequence of IR pulses.

This separation ensures that the timing-critical IR signal generation is never delayed, which is crucial for the AC unit to correctly interpret the signal.

// IR code sending task - Pinned to Core 1 for real-time precision
xTaskCreatePinnedToCore(
    toggle_ac_task,
    "Send AC code task",
    1024,
    NULL,
    0,
    NULL,
    1
);

🚀 Installation & Usage

Clone the repository:

git clone

Configure Wi-Fi Credentials: Open main.c and update the SSID and PASS macros with your network details.

#define SSID “YOUR_WIFI_SSID” #define PASS “YOUR_WIFI_PASSWORD”

Build and Flash: Using PlatformIO, build and upload the project to the ESP32.

Find the IP Address: Open the serial monitor to view the IP address assigned to the ESP32 once it connects to your Wi-Fi network.

Control Your AC: Open a web browser on any device connected to the same network and navigate to the ESP32’s IP address. Click the “Toggle AC” button to control your air conditioner.

🔮 Future Improvements

Full Remote Emulation: Decode and implement all buttons from the remote (temperature, fan speed, mode).

Cloud Integration: Connect the device to an MQTT broker for control over the internet.

State Feedback: Use a non-contact temperature sensor or a smart plug with power monitoring to confirm the AC’s state and display it on the web interface.

OTA Updates: Implement Over-The-Air firmware updates for easy maintenance.