---
title: "🚀 Building Stable Ethernet MQTT Communication with ESP32 and W5500"
url: "https://maker.wiznet.io/scott/projects/w5500%E3%82%92%E4%BD%BF%E3%81%A3%E3%81%A6esp32%E3%81%A7ethernet-mqtt%E9%80%9A%E4%BF%A1%E3%81%99%E3%82%8B/"
markdown_url: "https://maker.wiznet.io/scott/projects/w5500%E3%82%92%E4%BD%BF%E3%81%A3%E3%81%A6esp32%E3%81%A7ethernet-mqtt%E9%80%9A%E4%BF%A1%E3%81%99%E3%82%8B/md"
type: "UCC: User Created Content"
author: "Hiko"
author_url: "https://hikoleaf.hatenablog.jp/entry/2019/06/20/221403"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "Hiko"
original_url: "https://hikoleaf.hatenablog.jp/entry/2019/06/20/221403"
published: "2022-11-01"
language: "en"
tags: ["MQTT", "W5500"]
hardware: ["Espressif ESP32", "WIZnet W5500"]
likes: 4
views: 12731
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# 🚀 Building Stable Ethernet MQTT Communication with ESP32 and W5500

> Let's try MQTT communication with ESP32 ( Arduino core for the ESP32) using WIZnet's W5500 .

Original author: Hiko (source: https://hikoleaf.hatenablog.jp/entry/2019/06/20/221403)

## Components

- **Espressif ESP32** x 1 ([docs](https://www.espressif.com/en/products/socs/esp32))
- **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))
- Software: **Arduino IDE** ([docs](https://www.arduino.cc/en/software))

WIZnet parts: W5500 ([Datasheet](https://docs.wiznet.io/Product/Chip/Ethernet/W5500/datasheet?utm_source=maker&utm_medium=project&utm_campaign=w5500), [product hub](https://maker.wiznet.io/products/w5500/))

## Article

If you're developing an embedded application with the ESP32 and need more stable network connectivity than Wi-Fi can offer, using the **WIZnet W5500 Ethernet chip** is a smart choice. In a detailed blog post by [Hikoleaf](https://hikoleaf.hatenablog.jp/), the author walks through how to implement **MQTT communication over Ethernet** using ESP32 + W5500, powered by the Arduino development environment.

---

## 🔧 Project Overview

The tutorial demonstrates how to connect the **ESP32** microcontroller to a **W5500 Ethernet module** via **SPI**, then use MQTT to send and receive messages through a local broker.

### 🛠️ Core Components

- **ESP32**: Wi-Fi-enabled microcontroller with SPI support

- **W5500**: SPI-based Ethernet controller with built-in TCP/IP stack

- **Arduino IDE**: Used for code development

- **Mosquitto (on Raspberry Pi)**: Acts as a local MQTT broker

---

## 📦 Step-by-Step Implementation

**1. Hardware Wiring**
Connect the W5500 module to the ESP32 using SPI pins (MOSI, MISO, SCLK, CS).

**2. Arduino Library Setup**
Install the following libraries:

- [`Ethernet`](https://www.arduino.cc/en/Reference/Ethernet)

- [`PubSubClient`](https://pubsubclient.knolleary.net/)

**3. Code Implementation**

- Initialize Ethernet using `Ethernet.begin()`

- Connect to the MQTT broker with `PubSubClient`

- Send and receive messages on subscribed topics

**4. MQTT Broker Setup**
Install and configure **Mosquitto** on a Raspberry Pi to act as your MQTT server.

---

## 🧪 Example Code Snippet

```cpp
#include <Ethernet.h>
#include <PubSubClient.h>

byte mac[] = { 0x70, 0x69, 0x69, 0x2D, 0x30, 0x31 };
byte server[] = { 10, 0, 1, 5 };

void callback(char* topic, byte* payload, unsigned int length) {
  payload[length] = '\0';
  String msg = String((char*) payload);
  Serial.println(msg);
}

EthernetClient ethClient;
PubSubClient client(server, 1883, callback, ethClient);
```

This code initializes Ethernet, connects to the MQTT server, and listens for incoming messages.

---

## ✅ Why Use Ethernet on ESP32?

While ESP32 is known for its Wi-Fi capability, there are many reasons to choose Ethernet with W5500:

- 🚫 Avoid unstable or congested wireless networks

- 🔐 Improve security and isolation

- 📈 Ensure real-time data delivery in industrial environments

---

## 📘 Read the Full Tutorial

For complete wiring diagrams, full source code, and detailed setup instructions, check out the original blog post:

👉 [W5500を使ってESP32でEthernet MQTT通信する](https://hikoleaf.hatenablog.jp/entry/2019/06/20/221403)

This guide is a must-read if you're building an IoT system with **stable wired network communication using ESP32 and Rust or Arduino**.

---

Source: https://maker.wiznet.io/scott/projects/w5500%E3%82%92%E4%BD%BF%E3%81%A3%E3%81%A6esp32%E3%81%A7ethernet-mqtt%E9%80%9A%E4%BF%A1%E3%81%99%E3%82%8B/