Welcome to eBUS adapter 2!

This is set of instructions for building and using an eBUS adapter for communicating with an eBUS-enabled heating, ventilation, or solar system.


Version 2 of the eBUS board was mainly designed to avoid tuning the potentiometer. Many users had problems with the adjustment, especially due to the tolerance of the components, which made the fine tuning a bit tricky. Another complication was the type of UART and how to connect it (TX to TX or TX to RX).

All these problems are now supposed to be solved and you can connect a wide variety of UARTs to the adapter.

Furthermore, the set of features has been significantly extended:


The adapter consists of a base board and can optionally be used with an additional extension board which allows access to the eBUS via WLAN in conjunction with a Wemos D1 mini.

The following pages describe the assembly and testing of the soldered circuit board. The required components are listed here.


The assembled base and/or extension board can be used in different variants with Wemos and/or UART:

Additionally, a computer (like a Raspberry Pi) with ebusd is needed, as the Wemos with ebusd-esp does not replace ebusd but merely provides the serial interface in the WLAN.


Here is an overview of the individual components with their connections: schema

Wemos Usage

For using a Wemos D1 for communication with eBUS, a special firmware is required. It can be connected directly to the adapter like this:

Wemos D1 wiring

In order to use additional sensors with the extension board, a separate Wemos D1 is needed, which can not be used as an eBUS worker at the same time due to excessive latency.

Here are some links that contribute to the topic or contain basic information, most of which are in German: