Transition large installation to OpenHab?

Hello, and thank you in advance for any advice or thoughts you can share.

I am strongly considering moving my current installation over to OpenHab and would like to know if you think OH is the right choice. I currently have the following:

  • 40 nodes on my Zwave network
  • DSC1832 panel with 15 zones (and several more to add)
  • Davis weather station feeding my setup
  • 10 X10 MS14A motion sensors feeding my setup through a w800rf
  • Over 100 “virtual” devices holding status and values from various algorithms and scripts. (I.e. Approximately 20 devices devoted to values from my Davis weather station). I believe virtual devices in my current setup would be the same as what I’ve seen the community call “proxy items”.

I feel very good after my limited testing with everything but the x10 sensors. I have not found any comments on a binding that will allow me to interface my w800rf and thus receive signals from my x10 motion sensors. Can anyone offer any help or suggestions on making these work? They are critical to my installation and would be a deal-breaker if they cannot make the transition.

Secondly, do you feel OpenHab can handle hundreds of items in a setup? Some will be real items, others will be calculated or proxy items. The proxy items will be filled by scripts and rules.

Finally, can anyone speak to the stability and responsiveness of OpenHab when crossing complex rules with potentially hundreds of items?

Oh, here’s the kicker. I would love to run this from an RPi2. I have OH running on one right now. I’m just curious if the Pi + OH could handle a larger installation.

My installation has been in place for over 10 years, so it could probably stand to be trimmed a bit, but as I look over things I see very few unused events, scripts, or devices.

Thank you so much for taking the time to read through this and for any comments you have. I’ve very much enjoyed following many conversations on here about OH and hope to join the community in full.



If you can interface with it from the command line or a script (e.g. Pythpn) you can use the Exec binding. If you can interact with it directly over a serial device then the Serial binding should work. Beyond that I don’t think there is much chance of a new binding. Given the age of x10 and the fact that the majority of openHAB developers and users are in Europe where x10 never did gain popularity I am doubtful a new binding would be forthcoming unless you took that on yourself.

Define what you mean by “realtime”. OH does not have any strict real time capabilities like you might find in an embedded device. However if you just mean “really fast” OH can probably handle it but as with everything it depends on a lot of factors.

But I do know that many people on this forum have similarly sized setups on RasPi 2s so I wouldn’t be too concerned about its ability to handle it. Your biggest constraint will probably be RAM so if you are shopping around choosing a device with more RAM is better than one that say, has a better CPU but less RAM.

The way OH is architected the number of Items or rules you have should not impact stability or responsiveness. The limiting factor is how many simultaneous events from Items you need to process at the same time, not the total number of Items (ignoring the extended time to start with more Items).

If there is any instability it will be highly localized to a single binding (e.g. if zwave is causing problems it won’t degrade your other Items).

Of course it is possible to configure your setup where you can run into problems. For example if you have dozens of rules that all trigger from the same event you might see some delay as each rule is executed in its own thread which has its own overhead, but even then rules are usually really light weight code so we are talking milliseconds at the most and merging the logic can likely solve that problem if you have it. If not, moving some of the logic off to an external script or program could help as well but I think needing to do that would be highly unusual. I’ve found it unusual to have more than two rules triggered by the same event in my setup.

I appreciate your detailed response, @rlkoshak. I have taken the plunge based on the details of your response and multiple posts I’ve seen on similar topics. I will say I’m quite impressed with what I’m seeing. I come from a system that offers a webgui for the more basic functions (devices, events, etc). I won’t say moving to a coded environment was intimidating - I’d call it more daunting due to what I knew would be necessary to recreate what I had in the past.

I’ve decided to move away from X10 and the w800rf. The serial binding would do the trick in the right hands… mine aren’t the right hands. I am using the MQTT binding and hardwiring all my sensors now. I’m only a week into it, but I’m loving MQTT! So far, the only thing I’ll miss is my handheld remotes. I’ll have to find an alternative route for controlling lights and music (without using my phone).

Thanks again for your response. I’m hoping this is a patient community - I know I’ll have lots of questions as I grow into this system.



I think you will find that if you are willing to put in the work to try things and learn a bit on your own, which you have demonstrated, there will be no end to this community’s patients. Welcome aboard!