The M-Bus Master Hat is an add-on board designed for the Raspberry Pi which controls the physical layer of an M-Bus. It can be used in conjunction with a Raspberry Pi and software such as libmbus to provide a cost effective solution to allow you to connect to and read M-Bus slaves, such as water, heat and electricity meters that implement the wired M-Bus protocol.

The M-Bus Master Hat is fully compliant with the Raspberry Pi Hat specifications. It is compatible with any Raspberry Pi which includes the 40 pin header. This includes all current Raspberry Pi boards, from the Pi 1 Model B+ (2014) onwards, including the Raspberry Pi Zero. There are two models:
- Full size – suitable for the larger Model A and B Pis, sized per the picture above.
- Micro – the same size as a Pi Zero, per the picture down below.
All Hats undergo rigorous post-assembly checks and tests before shipping.
Both models are identical in function and only differ in size. Both models are compatible with all Pis from the Pi 1 Model B+ onwards.
To purchase please visit our shop.
Getting Started
Instructions on using the M-Bus Master Hat can be found here.
Features and More Details
See the datasheet for more details.
Full schematics are available for revisions:
Ordering
To purchase please visit our shop.
Included:
- One M-Bus Master Hat.
- Standoffs and nuts for attaching the Hat to a Raspberry Pi with mounting holes.
- Shipping within the UK.
Not included:
- A Raspberry Pi.
- Any M-Bus slave devices.
- Software, although full instructions are available here for getting libmbus running with the Raspberry Pi M-Bus Master Hat. There is also an open source M-Bus Master HTTP server for the Raspberry Pi compatible with the M-Bus Master Hat available.

Attribution
The M-Bus Master Hat is based on an M-Bus Master design available as part of libmbus.
libmbus License
BSD 3-Clause License
Copyright (c) 2010-2012, Raditex Control AB All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.