---
title: "ramses_esp_eth"
url: "https://maker.wiznet.io/Grace_Koo/projects/ramses-esp-eth/"
markdown_url: "https://maker.wiznet.io/Grace_Koo/projects/ramses-esp-eth/md"
type: "UCC: User Created Content"
author: "Grace"
author_url: "https://maker.wiznet.io/Grace_Koo/"
original_author: "Grace Koo"
original_url: "https://github.com/PWhite-Eng/ramses_esp_eth.git"
published: "2025-11-20"
language: "en"
tags: ["C/C++"]
hardware: ["WIZnet W5500"]
likes: 0
views: 1354
comments: 0
source: "WIZnet Makers (https://maker.wiznet.io/)"
---

# ramses_esp_eth

> A wired ESP32-S3 gateway that converts 868 MHz Evohome/Ramses II RF signals into MQTT for reliable smart-home integration.

Original author: Grace Koo (source: https://github.com/PWhite-Eng/ramses_esp_eth.git)

## 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/))

## Documents and links

- [ramses_esp_eth](https://github.com/PWhite-Eng/ramses_esp_eth.git) (code)

## Article

## Introducing the ESP32-S3 Evohome/Ramses II RF → MQTT Ethernet Gateway

[This project](https://github.com/PWhite-Eng/ramses_esp_eth.git) is a wired Ethernet gateway that captures 868 MHz RF signals from Honeywell Evohome/Ramses II systems and forwards them to an MQTT broker. A CC1101 handles RF reception, the ESP32-S3 processes the protocol, and the W5500 module provides a stable Ethernet link.
Although a Wi-Fi version (ramses_esp) already exists, this Ethernet-only design was created for users who need **maximum reliability** and a true **plug-and-play gateway**—a device you configure once, connect to Ethernet and power, and depend on continuously without worrying about wireless instability.

## Why is it interesting?

Most open-source Evohome/Ramses gateways rely on Wi-Fi, which can introduce latency,
instability, or disconnections—problems that are unacceptable in heating control.
This limitation naturally led to exploring an Ethernet-only approach in the first place.
This project instead uses **wired Ethernet (W5500)** and leverages the ESP32-S3's dual cores, dedicating one to RF processing and the other to networking. As a result, RF packets are captured consistently and reliably.

## What does the gateway actually do?

![](https://maker.wiznet.io/upload/ckeditor5/825279237%5F1763648771%2Epng)

The concept is straightforward:

- Receive 868MHz RF signals via CC1101

→ Parse them on the ESP32-S3 → Publish them to an MQTT broker via Ethernet

- And in the opposite direction:

→ Receive MQTT commands → Transmit them back over RF

In short, it acts as a bridge between wireless heating devices and MQTT-based smart home systems.

This makes it possible to:

- Monitor heating data in real time

- Automate TRV and boiler control

- Integrate a complete Evohome system with Home Assistant

## Design Highlights

A few noteworthy aspects:

- Ethernet-based, far more stable than Wi-Fi

- Dual-core FreeRTOS design ensures RF and network tasks never interfere

- CC1101 radio watchdog for automatic recovery

- Home Assistant MQTT Discovery support

- Full Ramses II/Evohome protocol handling

- The gateway is also designed to be plug-and-play: configure it once, connect Ethernet and power, and let it run continuously without user intervention.

  The project focuses on reliability, which is essential for any heating system gateway.

## Who is this useful for?

- Home Assistant users who want Evohome/Ramses II integration

- Anyone needing an alternative to Honeywell’s discontinued HGI80

- Users who want stable RF ↔ MQTT communication

- Developers studying 868MHz RF protocols

- Anyone who has struggled with Wi-Fi-based gateways dropping packets

## Conclusion

This project goes well beyond a simple ESP32 experiment.
It recreates the functionality of commercial hardware using open-source tools and affordable components—while providing stability, MQTT integration, and full protocol support.

Its dedicated Ethernet design removes the instability of Wi-Fi-based gateways and focuses entirely on delivering consistent, loss-free RF communication.
If you are working with wireless heating systems, RF protocols, or smart home automation, this is a project worth exploring.

---

Source: https://maker.wiznet.io/Grace_Koo/projects/ramses-esp-eth/