EMS bus interface board. Connect your Raspberry Pi to the EMS bus.
This board is a so called HAT for Raspberry Pi.
It connects the EMS bus to the serial port (UART) of the Raspberry Pi on pins GPIO14 and GPIO15.
Just press it on the Pi, connect the EMS bus wires and write your own software for the bus communication.
First a clear note: This board is NOT a substitute for the EMS Gateway! It does not run EMS-ESP. You cannot install software on this board.
The HAT is ONLY the hardware interface specific for the Raspberry Pi, it does not come with any API or software whatsoever.
You have to write or install this on the Pi yourself.
Do not buy this item if you expect that when you connect the HAT on the Pi that somehow magically the boiler parameters will appear on your screen.
In that case buy a S32 or E32 EMS Gateway, it will do just that.
If you like to write software and play with the low level UART of the Pi and the EMS bus, then this HAT could be a perfect item for you.
And again a second clarification because people still order this product all the time thinking it will run EMS-ESP somehow:
It does not. This product is just the electrical hardware interface between the EMS bus and the Pi.
If you want to communicate with your EMS boiler or heatpump and your home automation is running on a Raspberry Pi you should buy an S32 or E32 EMS Gateway and not this product. The Gateway will communicate via MQTT to the home automation on your Raspberry Pi.
You do not need this board for that purpose.
If you have further questions on this board use the contact form to email me before you decide to buy this product.
I will help you get the right product for you.
And now on with the specs of this board:
You can connect the HAT to the bus via the 3,5mm service jack or via the EMS/thermostat wires on the screw connector.
The board is compatible with all Raspberry Pi models that have a 40-pin header. These include:
- Raspberry Pi A+
- Raspberry Pi B+
- Raspberry Pi Zero
- Raspberry Pi 2
- Raspberry Pi 3
- Raspberry Pi 4
This set includes the complete board with the stacking header soldered on and a set of 14mm nylon standoff spacers with screws and nuts.
With this board you can safely connect a UART/serial port of your microcontroller or development board to the EMS bus.
The stacking header ensures perfect compatibility with the Raspberry Pi, but it can also be used for connecting other microcontrollers.
Because the EMS bus is about 16VDC, works with an offset and the signal in the top few volts, the RX signal needs to be stepped down to 0-3.3V or 5V.
TX works in the current domain so this board converts the TX signalling of the UART into a specific current signal for the EMS bus.
Did not understand anything of these technicalities?
That’s OK because the main reason I built this board is so you don’t have to worry at all about the electrical part of the EMS interface.
Just plug it onto your Pi and off you go.
The board is 3.3V and 5V UART compatible and works with all EMS, EMS+, EMS2 and Heatronic 3 and 4 boilers.
Aside from the Raspberry Pi, this board is also compatible with f.i. every Arduino, Atmel, ESP8266, ESP32, Wemos, NodeMCU and other microcontrollers.
For more information have a look at the product wiki.
The stacking header and the correct set of standoff spacers make it possible to add multiple HATs to the same Pi. Just make sure the other HATs don’t use the serial port of the Pi on GPIO14 and GPIO15. This HAT does not include a config EEPROM so if your other HAT has one this board won’t get in the way at all.
This board is NOT a substitute for the EMS Gateway!
The HAT is ONLY the hardware interface specific for the Raspberry Pi, it does not come with any software whatsoever.
You have to write or install this yourself, I can’t help you with that part.
Mourad D. (verified owner) –
Lubomír Holík (verified owner) –
Matěj Kraus (verified owner) –
Anonym (verified owner) –
good workmanship, all working great
Anonymous (verified owner) –
Not yet tested, build quality seems very good.