IoT Projects Part 1 : System Overview & Architecture

Introduction

The Internet of Things (IoT) is all about connecting devices, collecting data, and making intelligent decisions in real-time. In this project series, we’ll build a complete IoT ecosystem that integrates:

• ESP32 microcontrollers running different sensor/actuator projects.
• MQTT communication protocol for lightweight, real-time messaging.
• A PyQt5 desktop dashboard for monitoring and control.

This first part gives you a bird’s-eye view of the system and explains the role of each component before diving into the individual projects.

Why ESP32?

• The ESP32 is a natural choice for IoT because:
• Built-in Wi-Fi + Bluetooth → no extra hardware required for connectivity.
• Low cost, low power, and widely available.
• Supports multiple peripherals (GPIO, ADC, I²C, SPI, UART) for connecting sensors.
• Strong ecosystem (Arduino IDE, PlatformIO, ESP-IDF, Wokwi simulation).

In this series, we use 6 ESP32-based projects, each focusing on a specific sensor or actuator: LED/Button system, Weather station, Water level monitor, Load cell, Motion tracker, and Gas detector.

Why MQTT?

IoT devices need a way to communicate efficiently, and that’s where MQTT (Message Queuing Telemetry Transport) shines:

• Lightweight protocol – designed for constrained devices.
• Publisher/Subscriber model – devices publish data, others subscribe to receive it.
• Decoupled communication – sensors don’t need to know who is listening.
• Works seamlessly with the Mosquitto broker (used in this project).

MQTT ensures that your ESP32 devices and desktop dashboard stay in sync in real time.

Why PyQt5 Desktop Dashboard?

The ESP32 devices generate data, but you need a central control hub to monitor everything. That’s where the PyQt5 dashboard comes in:

• Modern desktop GUI with custom switches, charts, and indicators.
• Real-time updates using MQTT subscriptions.
• Interactive control – send commands back to ESP32 devices.
• Cross-platform (Windows, Linux, Mac).

This makes the system not just a data collector, but a user-friendly IoT control center.

System Architecture

Here’s the complete system design:

• The ESP32 devices act as data publishers (sensors) and command receivers (actuators).
• The Mosquitto broker handles message routing between devices and dashboard.
• The PyQt5 dashboard provides visualization, interaction, and centralized control.

Conclusion

This overview establishes the foundation for our comprehensive IoT system, highlighting how ESP32 microcontrollers, MQTT communication, and a PyQt5 desktop interface work together to create a complete IoT ecosystem. The modular approach allows for easy expansion and customization while maintaining reliable real-time communication between all components.

In the next part of this series, IoT Projects Part 2: PyQt5 Desktop Dashboard, we'll dive deep into the desktop application structure, exploring the Qt Designer interface hierarchy and the screen management system that provides seamless navigation between different IoT project modules.

That's all!

If you have any questions or suggestions, don’t hesitate to leave a comment below.