---
title: "MQTT Communication to Adafruit IO Using Dual-Port SP2302"
url: "https://maker.wiznet.io/TheoIm/projects/mqtt-communication-to-adafruit-io-using-dual-port-sp2302/"
markdown_url: "https://maker.wiznet.io/TheoIm/projects/mqtt-communication-to-adafruit-io-using-dual-port-sp2302/md"
type: "UCC: User Created Content"
author: "SecurePi"
author_url: "https://www.hackster.io/securepi1905/mqtt-communication-to-adafruit-io-using-dual-port-sp2302-e18dc9?f=1"
editor: "WIZnet"
editor_url: "https://maker.wiznet.io/"
original_author: "SecurePi"
original_url: "https://www.hackster.io/securepi1905/mqtt-communication-to-adafruit-io-using-dual-port-sp2302-e18dc9?f=1"
published: "2025-07-29"
language: "en"
hardware: ["WIZnet W5500"]
likes: 0
views: 1212
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# MQTT Communication to Adafruit IO Using Dual-Port SP2302

> Dual Ethernet SP2302 platform to publish data to Adafruit IO over MQTT

Original author: SecurePi (source: https://www.hackster.io/securepi1905/mqtt-communication-to-adafruit-io-using-dual-port-sp2302-e18dc9?f=1)

## Components

- **WIZnet W5500** x 1 ([docs](https://docs.wiznet.io/Product/Chip/Ethernet/W5500))

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

## **MQTT Communication to Adafruit IO Using Dual-Port SP2302**

MQTT Communication to Adafruit IO Using Dual-Port SP2302 (W5500)

![MQTT Communication to Adafruit IO Using Dual-Port SP2302](https://hackster.imgix.net/uploads/attachments/1855610/_ub7vpvHJG2.blob?auto=compress%2Cformat&w=900&h=675&fit=min)

### [**](https://www.hackster.io/securepi1905/mqtt-communication-to-adafruit-io-using-dual-port-sp2302-e18dc9?f=1#things)

### [**](https://www.hackster.io/securepi1905/mqtt-communication-to-adafruit-io-using-dual-port-sp2302-e18dc9?f=1#story)**Story**

Overview

**Dual Ethernet SP2302** platform to **publish data to Adafruit IO** over **MQTT**, utilizing:

- **eth1 (W5500 over SPI)** to gather Modbus or sensor data

- **eth0** for Internet/cloud communication

**field-to-cloud** architecture where the data-collection interface and Internet interface are physically isolated — a common pattern in industrial IoT gateways.

#### **What You’ll Need**

- SP2302 running dual-port firmware

- WIZ850io module (W5500-based) properly connected to SP2302 SPI

- Internet access via `eth0`

- Active Adafruit IO account

- Feed name created (e.g., `sensor1`)

- Your Adafruit **username** and **AIO Key**

#### **Step 1: Install MQTT Library on SP2302**

```plaintext
bash
sudo apt update
sudo apt install python3-pip -y
pip3 install paho-mqtt
```

#### **Step 2: Adafruit IO MQTT Setup**

#### **Required Settings:**

- **MQTT Broker**: `io.adafruit.com`

- **Port**: `1883` (unencrypted) or `8883` (TLS)

- **Topic**: `username/feeds/feedname`

- **Username**: Your Adafruit IO username

- **Password**: Your AIO Key

#### **Step 3: Python Demo Script for Publishing Data**

```plaintext
python
# sp2302_mqtt_to_adafruitio.py

import time
import paho.mqtt.client as mqtt
import random

# --- Adafruit IO MQTT Configuration ---
ADAFRUIT_IO_USERNAME = 'your_adafruit_username'
ADAFRUIT_IO_KEY = 'your_aio_key'
ADAFRUIT_IO_FEED = 'sensor1'

MQTT_BROKER = 'io.adafruit.com'
MQTT_PORT = 1883
MQTT_TOPIC = f"{ADAFRUIT_IO_USERNAME}/feeds/{ADAFRUIT_IO_FEED}"

# --- Bind MQTT client to eth0 explicitly (optional) ---
MQTT_LOCAL_BIND_IP = '192.168.1.100'  # eth0 IP (Internet-facing)

client = mqtt.Client()
client.username_pw_set(ADAFRUIT_IO_USERNAME, ADAFRUIT_IO_KEY)

# Optional: bind to eth0 to ensure traffic doesn't go through eth1
client.bind_address = MQTT_LOCAL_BIND_IP

client.connect(MQTT_BROKER, MQTT_PORT, 60)
client.loop_start()

def main():    print(f"[✓] Publishing data to Adafruit IO topic: {MQTT_TOPIC}")    while True:        simulated_value = random.randint(0, 100)        client.publish(MQTT_TOPIC, simulated_value)        print(f"[>] Sent: {simulated_value}")        time.sleep(5)

if __name__ == "__main__":    main()
```

#### **Step 4: Run the Script**

```plaintext
bash

python3 sp2302_mqtt_to_adafruitio.py
```

Check your Adafruit IO dashboard — your `sensor1` feed will now update every 5 seconds with simulated values.

#### **Verifying Network Routing**

Ensure:

- W5500 (`eth1`) is isolated for local/field communication (Modbus, sensors)

- MQTT traffic to Adafruit goes through `eth0` (main NIC)

You can confirm routing using:

```plaintext
bash
ip route
ip addr show eth0
ip addr show eth1
```

#### **Results**

![](https://hackster.imgix.net/uploads/attachments/1855613/1932831749109114956.png?auto=compress%2Cformat&w=740&h=555&fit=max)

#### **Use Case**

![](https://hackster.imgix.net/uploads/attachments/1855614/wechat_20250605154756_hweYeM7DMA.png?auto=compress%2Cformat&w=740&h=555&fit=max)

#### **Optional: Enable TLS for MQTT (More Secure)**

Change port to `8883` and add:

```plaintext
python

client.tls_set()  # Uses default certs
```

#### **Summary**

- SP2302 uses dual Ethernet (eth0 and eth1)

- MQTT publishes to Adafruit IO via `eth0`

- Sensor/modbus data (if any) flows in from `eth1`

- This creates an industrial-grade cloud-connected setup with physical a

---

Source: https://maker.wiznet.io/TheoIm/projects/mqtt-communication-to-adafruit-io-using-dual-port-sp2302/