OH2, Homematic and Enocean in multiple Faraday cages

I live in a house in Switzerland that was built in 1993. This means that the floor of each storey is 30 cm thick reinforced concrete, i.e. each storey is effectively a Faraday cage, and wireless communication is severely limited.

The house has 4 storeys: cellar, ground floor, first and second floor.

I have wifi coverage in all four storeys and my Homematic stuff works on all four storeys too thanks to the LAN Gateway.

I would like to use Enocean switches for the lighting, but I can’t work out how best to do this. My initial tests have revealed that the Enocean signal does not carry to an adjacent storey, even with an Enocean repeater.

Obviously, the whole thing is controlled by OpenHAB (less obviously, OH2), which runs on a PC Engines APU board under Ubuntu. The board has an Enocean USB receiver attached.

I!d like to have as much hardware as possible in the cellar: I don’t think that strange elrctronic boxes all over the place add to the ambiance in the house.

Does anyone have any suggestions or experience that they can share? Other than dumping Enocean? I have a sneaking feeling that MQTT might be my friend…?

Steve

I have a solution to my problem, based on MQTT. I have built a prototype using a Raspberry Pi 1 running OH2 with MQTT and EnOcean installed. The Raspberry Pi has a TCM310 on its back.

I have installed an MQTT broker on my central server and the Pi, which is only an EnOcean relay, publishes its event bus to the MQTT broker. The central server subscribes to those commands and takes it from there.

Positives:

  • it works;
  • Raspberry Pi 1 can run (minimal) OH2;
  • MQTT is really easy to use;
  • could add further decentral functionality if necessary.

Negatives:

  • EnOcean signal almost needs a line of sight to the receiver;
  • another box on each storey (ambiance-, cost+)

I’m going into production with this solution using Raspberry Pi 3’s so I can boot from a USB stick.

Steve

Hi Steve

Is this still the best solution from your experience? What kind of enocean to mqtt gateway did you use?

Cheers,
Andres (also in Switzerland)

Hi Andres

I did what I wrote in my second post. However, given that I have EnOcean switches on 3 floors and that EnOcean signals would not reliably pass from one floor to another, I installed a gateway on each floor.

I used Pi 3s, as I mentioned, that were booted from USB sticks. MQTT uses wifi to communicate with the central OH2 server, though I have doubts about the reliability of the Pi 3’s wifi: I think they have hardware problems, though they claim it is only the drivers.

You can implement the EnOcean-MQTT bridge easily with OH2.

I even found some nice round white cases for the Pi 3 so they don’t offend the eye when screwed to the wall.

Steve

Hi,
I had a similar challenge which I currently solved as follows - perhaps this approach will help you solving your problem:
My server-hardware with openhab2 on a unix system is stored in the cellar and a raspberry works in the first floor (connected over lan).
The pi (without OH) serves different USB-adapters, one of this is an EnOcean-Stick (USB300) and provides the Enocean signals over ser2net to the lan.
Aditionally I had to install socat on my unix server for connecting to the serial port of my pi and of course the enocean-binding in oh2.

Hi Rainer

That’s an interesting approach that I never thought of. Would it work for multiple Pis though? (I’m not really familiar with ser2net.)

Steve

Hi Steve,
what do you mean with “multiple Pis though”?
In the config-file of the actual enocean-binding (1.9) you can only define one serial port.
So unfortunately you can connect your OH2 server only to one enocean-adapter (running only on one pi with ser2net).

Perhaps one of the next versions of the enocean-binding could manage different bridges - like the rfxcom-binding (it would be nice).:wink:

That’s what I thought: the OH EnOcean binding only supports one serial port so could only support one bridge using ser2net.

Steve