Wiznet makers

👤AUTHOR

A maker/embedded developer demonstrating how to use the WIZnet W5500 Ethernet controller with an STM32 microcontroller to implement a full MQTT client stack.
The series (PART 7) focuses specifically on network-level MQTT operations with publish/subscribe messaging.

🔗 YouTube Video: https://www.youtube.com/watch?v=Qr-dgzsofiY
 

🎯PROJECT DESCRIPTION

Created on December 13, 2025  ~ December 17,2025

This video shows how to configure an STM32 microcontroller to communicate over Ethernet using the W5500 hardware TCP/IP controller and connect to an MQTT broker.
The goal is to enable the STM32 to act as a fully functional MQTT client, capable of:

• Publishing sensor data to an MQTT topic
• Subscribing to control topics for remote commands
• Handling network connectivity reliably over Ethernet
• Supporting real-time data exchange between embedded device and server/cloud

Unlike simple TCP examples, using MQTT allows efficient publish/subscribe messaging—ideal for IoT and remote monitoring.

🧩KEY COMPONENTS USED

🧠 Hardware

• STM32 Microcontroller (any Cortex-M series supporting Ethernet + SPI)
• WIZnet W5500 Ethernet Controller – provides hardware TCP/IP stack
• Ethernet PHY + RJ45
• Optional sensors/actuators interfaced with STM32

🔌 Network & Protocol

• Ethernet physical link via W5500
• MQTT protocol (TCP 1883)
• MQTT broker (could be local or cloud, e.g., Mosquitto)

🧠 SYSTEM OVERVIEW

[STM32 MCU]
         │
 SPI  │
        ▼
  [W5500 Ethernet]
      │
Ethernet
      │
 [MQTT Broker (server/cloud)]
      ├── Publishes
      └── Subscribes

Here the STM32 publishes its sensor states and receives commands using MQTT topics. W5500 handles all TCP/IP protocol offloading so the MCU can focus on application logic.

https://controllerstech.com/stm32-w5500-mqtt-client/ 

✔VIDEO LESSONS

🔹 1) W5500 as network interface

The W5500’s hardware TCP/IP stack allows stable Ethernet communication with minimal STM32 overhead.

🔹 2) MQTT Implementation

Implemented as a client that:

• connects to a broker
• subscribes to topics
• publishes data
• handles reconnect logic

This enables real-time IoT control without Wi-Fi or external networking stacks.

MQTT uses a publish/subscribe system with three main parts:

1. Publisher – The device or program that sends data.
   Example: A temperature sensor publishing the current room temperature.
    
2. Subscriber – The device or program that wants to receive data.
   Example: A mobile app that shows the temperature reading.
    
3. Broker – The middleman (server) that connects publishers and subscribers.
   Example: An MQTT broker like Mosquitto, HiveMQ, or EMQX.

🔹 3) Publish & Subscribe Patterns

Sensor data can be periodically published, and remote commands (e.g., actuators) can be handled via subscribed topics.

🧪USE CASES

• Embedded IoT monitoring
• Industrial sensor networks
• Real-time control systems
• Remote data logging dashboards
• MQTT-based automation
• Home/Building automation with Ethernet connectivity

🧠ENGINEERING INSIGHTS

💡 Reliable Networking

Using W5500’s hardware TCP/IP drastically simplifies implementing higher-level protocols like MQTT on resource-limited MCUs.

🔌 Offloaded Protocol Stack

The MCU does not run full TCP/IP or network stack—W5500 handles ARP, IP, TCP, UDP—reducing timing issues and memory pressure.

📡 MQTT Efficiency

MQTT’s lightweight publish/subscribe model fits embedded platforms where:

• bandwidth is limited
• connection reliability matters
• multiple endpoints share topics

📡TUTORIALS AND PROJECTS

https://controllerstech.com/stm32-hal/w5500-ethernet-series/#google_vignette

Wiznet Maker site

STM32 Ethernet with W5500 (PART 2) : https://maker.wiznet.io/sophia/projects/stm32%2Dethernet%2Dwith%2Dw5500%2Dpart%2D2%2D%2Dtcp%2Dserver%2Dreceive%2Decho%2Dcontrol%2Dled%2Dvia%2Dethernet/

STM32 Ethernet with W5500 (PART 5): https://maker.wiznet.io/bruno/projects/stm32%2Dethernet%2Dwith%2Dw5500%2Dpart%2D5%2D%2Dstm32%2Das%2Dhttp%2Dwebserver%2Dled%2Dcontrol/