Integrating legacy light switches and buttons

I am considering options to connect existing light switches and buttons into OH2. The lights are already a mix of Philips Hue and Ikea Trådfri. This is an older house, where I would now like to remove relays and other redundant thick wires, while keeping the existing “retro” plates and switches.

When the Osram Lightify binding was announced, I asked in another post if the Lightify Pro PBC could be supported. That is a nice little box, which exemplifies what I am looking for:

  • Input: up to 4 light switches or push buttons (I could also use 8 :slight_smile:)
  • Output: ZigBee or RS485/Modbus
  • Size: small enough that it can be placed in junction boxes and wherever there were relays

Things you could do:

  • Use a push-button, with the short press to switch a light on/off (legacy “relay” mode), and long presses to dim, etc.
  • Reuse a legacy light switch, using any change of state (from on to off, or from off to on) as if it were a push-button action
  • Act on presses from multiple buttons to change scenes (e.g. press two buttons = all 10 lights on/off)
  • Use Up/Down button as an alternative way to control dimming

This is a narrow multi-floor unit, and I do not have enough space in the ducts to have all wires go to the main rack (even as they are going to be thinner than before, as they carry only on/off signal). However, as it already had boxes with (noisy!) relays in each floor, I would reuse that space for I/O modules. I am still not sure I trust ZigBee for the very long-term, so I would appreciate any tips that also take into consideration RS485 or some other bus solution.

With the control taking place in OH, you’re not limited to a technology or particular device for your inputs. You can have OH do the protocol mediation. Generally speaking, you’ll want to use a radio technology (unless you intend to embark on a full renovation of your house) for your inputs, but you can even mix radio and wired tech, so if you e.g. have free wires running to a switch place, you can put that to a IP gateway for that technology. There just happen to be no wired systems beyond KNX (which requires a bus) and all the proprietary stuff (that you shouldn’t be starting with for this purpose), so nothing to recommend.
You may want to use that ZigBee input box you have for a 1:1 control of particular ZigBee lights if you insist on no-latency ‘smooth’ dimming experience through switches, but generally speaking, you will not want to use ZigBee for inputs. ZigBee lights are popular, but there’s very little choices in switches, and practically none for non-lighting applications.

Consider ZWave actuators. There’s devices from Fibaro and Qubino that are small enough to fit below most retro plates and switches. They control the directly attached light from the directly attached switch, but you can attach another (‘blind’) switch, and you can even activate functions such as triple click on the primary switch.
These you can map in OH to your Hue lights (I assume you have a Hue bridge connected to OH).
I have all mains devices use ZWave actuators, and I have some Hues, too. They nicely play with each other, orchestrated by OH to form light scenes. With scenes, you usually don’t access the Hues any longer through switches or remotes anyway.

Thank you, Markus, for the prompt and detailed reply. I too tend to lean towards a wired solution for the switches. So, you are saying that on the wired side I should not even bother looking further at alternatives to KNX (e.g. Modbus, Souliss)?

I had seen these KNX interface boxes, which were about as small as the one by Osram, only wired:

  • Feller part number 3875-4.EIB (4 inputs) or 3875-2.EIB (2 inputs)
  • Theben part number 4969204 TA4 (4 inputs)

Any thoughts, on these, or something like these?

It is easy for me to be fascinated by some technical details. But only someone with a lot of experience can advise on a good solution that I can be grateful for in a few years :slight_smile:

Thanks again!

Yes, but KNX is probably no good idea either.

Yes, get away from the details. You need to start at the top level instead.

First, no proprietary systems.

KNX requires an IP gateway, a programming software, and, most important: a wired bus to connect ALL of your switches and lights.
Where do you want to go long term (all room lights?), what’s your wiring situation, and how much time and money will you be willing to spend on changing that ?
You might be starting with KNX when building a house, there you can put the bus into every room, but in older houses, even with just a partial amount of lights etc. to become part of the home automation setup, KNX is way to much effort to install, as is any other wired technology.
They’re unflexible as your ideas what to (also) automate will change over time that you haven’t thought of in the first place.
You want a radio solution.
As you like details, check out e.g. this.

Thank you, Markus, for your precious thoughts.

even with just a partial amount of lights etc. to become part of the home automation setup, KNX is way to much effort to install

I was considering a bus approach only to connect the switches. For the lights, it would have been Zigbee LL (or some other future wireless system).

Yes, but KNX is probably no good idea either.

Because of the need to pull extra wires, or for what other reason? (Note that I already excluded KNX for the actual lights - it would be limited to get the input from the switches.)

I already have to open the boxes (even if using wireless couplers), and something like KNX would allow for a tree topology, so I am not concerned by the one-time job of adding some bus wiring.

You may want to use that ZigBee input box you have for a 1:1 control of particular ZigBee lights if you insist on no-latency ‘smooth’ dimming experience through switches

Smooth dimming was indeed a goal, after a disappointment with the limited, granular dimming allowed by traditional “dimmable” LED bulbs.

As for latency, since the lights use Zigbee LightLink, which I believe doesn’t officially support direct connection between switches and lights, I suppose the technology used for the switches would not make much of a difference?

Indeed, I was thinking of using OH for the protocol mediation.

The difficult remaining decision for me is what solution (wired bus, or wireless) to use to connect the existing switches/buttons (which are not smart, and I won’t replace with smart ones). It boils down to long-term maintenance, and component costs.

Your KNX-for switches only would certainly make for an unusual (and for that purpose, expensive) solution, and as such no good idea. KNX is reasonable only if you really manage to pull wires to all of your switches AND lights. But you already said you don’t.

Again: drop the detail view, start at the top level.
You’re missing some important points.
First, you can and should pull as many wires to a central location (switchboard) as possible, there you can still choose the technology to attach them to.
Second, while you have some ZigBee lights, to take them as the starting point for your home planning activities is the wrong way of looking at things. Long term, you’ll want ALL of your lights to become part of your home automation setup, and pretty sure you can’t/won’t exchange all of your lights by bulbs with builtin ZigBee.
Third, speaking as someone with experience in this, it’s also a good idea to have a fallback solution that works if your home automation should fail. That is, directly wire switches to lights ! At least one per room. So you will need in-wall controllers anyway. But since there’s few to none in ZigBee, you need to move to a different technology.
That’s why I’d point you to my original recommendation of going ZWave. Those are actuators without switches that you can put below and connect to your existing switches. They do can control the ceiling lights (the wires will still lead to the switch, obviously) AND they can detect extra switching (e.g. triple-click) that you can link to your ZigBee lights through OH mediation.
Smooth dimming will work fine for those directly attached lights, too. Dimming just might become a problem if you have to go through protocol mediation. But as I said, in a smarthome you won’t be actively using manual dimming capabilities any more.

I will consider ZWave, thank you.

In the ducts, I do have room for extra bus wiring, but not to carry all light and switch cables to a single central location. That would certainly be high on my wish list if I ever was to build my own house :slight_smile:

pretty sure you can’t/won’t exchange all of your lights by bulbs with builtin ZigBee.

Why not? Offerings like Ikea’s Trådfri are making this much more affordable than it used to be.

First, who wants to live in an all-Ikea house ?
Second, remember all those lamps with non-exchangeable builtin lights/bulbs, particularly nowadays as every lamp manufacturer is moving towards LED.
Third, a smarthome is more than just lighting. Don’t forget about all those non-lighting applications such as roller shutters and all the sensor stuff.