esp-arduino-ebus
ESP-based Wi-Fi firmware for eBUS adapter hardware
Warning: Do not power your adapter from a power supply on eBus terminals - you will burn the transmit circuit (receive may still work)!
To get more info navigate to wiki
esp-arduino-ebus is an open-source firmware for EBUS to WiFi Adapter Module.
It turns the adapter into a network-connected eBUS interface with TCP, MQTT, HTTP, and Home Assistant support — suitable for monitoring and controlling eBUS-based heating systems.
⚠️ This firmware is designed to run only on supported eBUS adapter boards.
It is not intended for bare ESP modules without the required eBUS interface circuitry.
What This Project Does
- 🔌 Connects to eBUS heating systems (Vaillant and other eBUS-compatible HVAC equipment)
- 📡 Bridges the physical eBUS line to Wi-Fi / Ethernet
- 🌍 Exposes eBUS traffic over TCP sockets compatible with tools like
ebusd - 📊 Publishes data to MQTT for smart home integration
- 🏠 Supports Home Assistant autodiscovery
- ⚙️ Provides a web interface for configuration and diagnostics
Required Hardware
This firmware requires a compatible eBUS adapter board, which provides:
- Proper eBUS level shifting and electrical protection
- Safe bus power handling
- Signal conditioning (PWM / comparator circuitry)
- Reliable physical connection to the eBUS line
Supported hardware revisions include multiple ESP32-based eBUS adapter boards maintained alongside this project.
❌ Flashing this firmware onto a generic ESP8266/ESP32 module will not work.
🧠 INTERNAL Firmware Mode
In addition to acting as a network bridge, esp-arduino-ebus offers an advanced INTERNAL firmware mode, allowing the adapter to behave as an active, autonomous eBUS participant.
Key INTERNAL Features
- 🧾 Internal command store for eBUS messages
- 💾 Persistent storage in flash, restored after reboot
- 🔍 Automatic eBUS device scanning
- 🔄 Active and passive operation on the bus
- 📡 Full remote control via MQTT or HTTP
INTERNAL Control Capabilities
- Insert or remove stored eBUS commands
- Send single or periodic commands
- Publish stored values on demand
- Enable filtering and forwarding rules
- Trigger bus scans and internal resets
This mode enables standalone operation without requiring external software such as ebusd.
Smart Home Integration
- Native MQTT support
- Home Assistant autodiscovery
- Seamless integration into existing automation setups
- Suitable for dashboards, logging, and energy optimization
Why Choose esp-arduino-ebus?
- ✅ Designed for real eBUS adapter hardware
- 🔓 Fully open source
- ⚡ Low-power, always-on operation
- 🔧 Flexible: bridge mode or INTERNAL standalone mode
- 🧩 Compatible with existing eBUS tools and ecosystems