Smart Environment Node

This project implements a connected environmental monitoring node using an ESP32 development board. The node reads temperature and humidity from a DHT11 sensor, light intensity from an LDR, displays the values on an SSD1306 OLED screen, triggers an alert LED when thresholds are exceeded and uploads the measurements to a cloud service via WiFi (HTTP or MQTT).

Features

• Modular architecture with distinct classes for sensors, display, connectivity, filtering and alerting.
• Configurable pin assignments and thresholds via include/config.h.
• Moving average filtering to smooth out sensor readings.
• Automatic WiFi reconnection and cloud upload retries.
• Support for ThingSpeak (HTTP) or generic MQTT brokers.

Directory Layout

include/            Public header files
├── config.h        Global definitions and settings
├── sensors/        Sensor interfaces
│   ├── DHTSensor.h
│   └── LightSensor.h
├── display/        OLED display wrapper
│   └── OledDisplay.h
├── connectivity/   Network and cloud interfaces
│   ├── WiFiManager.h
│   └── CloudUploader.h
└── utils/          Utility classes
    ├── DataFilter.h
    └── AlertManager.h

src/                Implementation files
├── main.cpp        Application entry point
├── sensors/
│   ├── DHTSensor.cpp
│   └── LightSensor.cpp
├── display/
│   └── OledDisplay.cpp
├── connectivity/
│   ├── WiFiManager.cpp
│   └── CloudUploader.cpp
└── utils/
    ├── DataFilter.cpp
    └── AlertManager.cpp

platformio.ini      PlatformIO build configuration
README.md           This file

Getting Started

1. Install PlatformIO in VS Code.
2. Clone this repository to your machine.
3. Create a secrets.h inside include/ (and add it to .gitignore) or override credentials in platformio.ini via build_flags.
4. Connect the hardware according to the wiring diagram described in docs/wiring-diagram.md (not included here but referenced in the iot_project_structure.txt file).
5. Build and upload the firmware to your ESP32 using PlatformIO.

Customisation

Adjust threshold values, timing intervals and pin assignments in include/config.h to suit your specific hardware setup. Use the FILTER_WINDOW_SIZE constant to modify how aggressively the moving average smooths the readings. To switch between ThingSpeak and MQTT uploads simply leave the THINGSPEAK_API_KEY as the default placeholder or set it to your actual ThingSpeak key.