[NEWS] Reliable Ethernet-Based Smart Home Controller with STM32 + W5500
A DIY STM32 smart home controller with WIZnet W5500 delivers reliable Ethernet-based automation and seamless ESPHome integration for Home Assistant.
News: DIY STM32 Smart Home I/O Controller – Boosting Reliability with WIZnet W5500
Introduction
Home automation enthusiast kshypachov has built an impressive custom STM32-based Smart Home I/O Controller, gaining attention in the Home Assistant community. This DIY device goes beyond a personal project, showcasing how ESPHome, Home Assistant, and wired Ethernet can come together to deliver a highly reliable, real-time home automation solution.
At the heart of this controller lies the WIZnet W5500 Ethernet chip, selected for its proven performance in creating stable, low-latency network connections—especially important for smart home applications where reliability is non-negotiable.
Project Overview
Project name: f411_io_mod
Core functions:
- 8 digital GPIO outputs (ideal for relays, LEDs)
- 4 analog inputs (sensor monitoring)
- UART, CAN, SPI ports for extensibility
- Seamless ESPHome integration
Hardware specs:
- STM32F411 MCU (ARM Cortex-M4)
- WIZnet W5500 Ethernet chip (SPI interface)
- External power supply support with protection circuitry
- Designed for DIN rail mounting (professional enclosure-ready)
GitHub: kshypachov/f411_io_mod
Why WIZnet W5500?
Instead of using a traditional ESP32 Wi-Fi-based module, the developer chose a wired STM32 + W5500 Ethernet solution, citing the following key reasons:
Superior reliability in fixed installations (no Wi-Fi dropouts)
Low latency, ideal for real-time automation triggers
Full compatibility with ESPHome, even over Ethernet
"Wi-Fi is a great solution, but it’s not always 100% reliable. With Ethernet, my automation setup is much more stable and consistent."
– kshypachov, via Reddit
Technical Highlights
ESPHome over UART-to-Ethernet bridge
ESPHome communicates with the STM32 via Ethernet, with the MCU handling actual I/O control.
DIN-rail form factor
The PCB and enclosure are designed for professional deployment in home distribution panels.
Clear W5500 implementation examples
SPI setup, MAC/IP assignment, and YAML snippets are provided in the repo for easy replication.
Conclusion & Outlook
This project showcases how WIZnet’s W5500 continues to be a top-tier choice even in modern DIY and maker projects, especially where network stability and real-time performance are critical.
As the Home Assistant and ESPHome ecosystems grow, designs like this open new possibilities for professional-grade DIY smart home systems. With further development, this approach could integrate well with other WIZnet modules, such as the W6100 or WizFi360, for hybrid network support.