Wired control bus for a new house

Hi there,

New user here :slight_smile: Right now I’m building a new house (in EU/RO) and I’m looking into ways to build my electrical installation in a Home Assistant compatible way.

I’m quite concerned by the security aspects of radio-communications and WiFi and I’m aware that this makes me to stay out of the HA enthusiast crowd, those ready to throw in a bunch of ESP-32 devices over the WiFi :smiley: . My problem with this approach is security. I know about firewalls, multiple WiFi zones, strong-passwords, authorization etc. Still, I don’t want to go with WiFi except some non-essential appliances such as, say, light bulbs.

There are lots of buses wired there, the most prominent being KNX and their proprietary software that only run on Windows! I personally would like to use RS-485. Or Ethernet. Or some other simple and open bus.

Let me explain the main idea of the house logic:

  • no wall-switches but a couple of ethernet-connected touch screens (made from Odroid parts). Some motion sensors will also be needed here, without WiFi - so here is the first kind of bus-connected devices I’m looking for.
  • each load will have their own wiring from the main switchboard. Many of the loads would be shutter motors and lights. I also plan to have some dimmable lights
  • try to be future proof as HA is addictive and I foresee myself endlessly tinkering with it :slight_smile:

I’m right now exploring the switchboard appliances. This one, IPX800 from GCE shows the idea, but problem is that HA integration for it uses polling and not MQTT, for instance. But what are the options for the dimmers? KNX dimmers are expensive, require ETS and that ETS only work on Windows - which I don’t use - and also is too expensive for my only house building.

Finally I guess I’m not the only one trying to achieve this. Where should I look for RS-485 (or other open bus, MQTT compatible) devices like switchboard dimmers, relays, sensors. Please note I have electronics DYI skills, but power devices I’d like to have them reliably built :wink:

Thanks guys :slight_smile:

Z-Wave is a wireless local mesh network that can have encrypted communication. It is designed for the smart home with low overhead and battery friendly features. Standardization allows products from multiple vendors but you must buy devices for your world region to avoid incompatibilities.

Thanks @WallyR ! While I explored Sonoff devices, I failed to notice these :smiley: As I did not found a datasheet, may I ask: are these also relays able to remotely command the light bulbs or are they disconnecting lights only in case of overload?

I have actually no idea.
I just stumbled over them in search of other product I did on their site and remembered th RS485 picture in the line up of features. :slight_smile :slight_smile:

@Prodigyplace thanks for the reply. The WiFi itself also uses advanced encryption, and still can be hacked. Don’t get me wrong, I’ll still use WiFi for my mobile phone and HA-interface, but what I try to achieve here is to reduce the attack surface. Many WiFi devices = many entry points.

Maybe Homematic, a german brand, could be interesting too.


Only the newest versions of Wi-Fi ( the CORRECT trademarked spelling) with WPA3 Enterprise level encryption are advanced and not hacked. People have not yet hacked the WPA3-Personal preshared key version because it is so new and not widely supported yet.

Full disclosure: I am a trained Wi-Fi engineer on a team supporting over 15,000 users, some with smart home equipment… This equipment will not function on our current WPA2-Enterprise encrypted network. We have not yet moved our network to WPA3.

well, @WallyR , this looks to be what I’m looking for indeed. They have those dimmers also:

Once I’ll try them I’ll be able to mark your reply as the “solution”. Thanks a lot!

EDIT: it looks these are designed for yet another proprietary solution, HomeMatic IP. I found lots of this kind of stuff. I think I’ll end-up by doing it my way, with a relay board and a Beagle Bone. :thinking:

I think the RS485 port is a standard protocol, but I am not sure of course.
I do have Homematic thermostats running in HA and there is several ways to get those into HA, both for Homematic IP, Homematic RF and Homematic wired devices.
I use Debmatic for this, which emulates their gateway software in a debian package, but their CCU2 and CCU3 gateways are ported as HA addons too.

I think you should have enough faith in WPA2 if your password is complicated enough. For example a password like immortal-saute-fixate-campfire will take many many years to be hacked with 3080 Ti.

Of course don’t listen to me If you have the nuclear button in your home😂

It looks like HomeMatic is a proprietary solution and unfortunately it comes with the usual kind of problems these solutions have: Alerts – Home Assistant . I guess it’s not what I’m looking for.

Well, it is your decision to make

Try to at “din rail” to Google searches then you avoid all the light consumer products.

WPA and WPA2 is safe, but WPS is definitely not.

Open source board https://boneio.eu/

1 Like

Hey! Looks nice, thanks for pointing me to it. Actually, since my initial post I’ve settled on the Beagle Boards Black, pushed there by the lack of RPIs. It’s a nice board. I’ve also moved into the house, and I was just looking for some input solutions for my BBB. Those inputs are needed for the system to know when things are on or off, shut or open, things like that. So the BoneIO may be the solution.