Preparing electrical work for a smart home new construction

Hello everyone,

we are currently planning our new building, in which we will install the electrical system ourselves (electrician in the family).

I would like to consider the topic of [Smarthome] early on, even if it should not be installed from the very beginning. I would appreciate tips from those who have already done something like this.

So far, the plan is to execute the switches (e.g., for lights, blinds, etc.) as push buttons and to run them with separate cables via relays in the control cabinet, thereby switching the 230V lines.

In addition, I want to provide window contacts and sensors (temperature and humidity or motion) in all rooms and be able to query them later via the 24V lines as well.

I am interested in what else I should incorporate early on to be prepared for later use of a [Smarthome]. I want to avoid wireless connections and pure bus systems if possible.

As a computer scientist, I am considering using a Raspberry, but it seems to me that even with expansion boards, it has too few connections.

I look forward to your tips and suggestions. Also gladly links for reading up on the topic.

Best regards from Westerkappeln,
Jens

I want to avoid radio connections and pure bus systems if possible.

These are mutually exclusive....

As a computer scientist, I am considering using a Raspberry, but it seems to me that even with expansion boards it has too few connections.

Possible use as a web server... rather unsuitable as a central unit for home automation... or associated with a lot of tinkering...

Which system besides Raspberry is favored? "Smarthome" is not a protected term similar to "turnkey" and can mean anything from a multiple socket with remote control in the corner to a house that thinks for itself and performs many tasks before you even think of it.

Read this at the beginning:

Hello Jeti79,

As a software developer, I faced the same problem this year. How to create the wiring in order to install or be able to install home automation.

My solution was then a star-shaped wiring from the consumers (sockets, roller shutter motors) and sensors (push buttons, 6-fold push button from G**a, glass break and opening sensors) to the distribution cabinet.
Ok, the distribution cabinet is quite something.

For home automation, I used Homematic Wired. The central control software runs on a BananaPi, as it is enormously faster than the original target hardware – installation without problems.

I implemented some light switches / dimmers with Eltakos, because I didn’t want to risk a total failure if something went wrong with the home automation. But so far everything works perfectly.

It is really important that you are clear in advance about what you want to achieve and how!
Lots of thinking, reading, exchanging ideas, then it will work out. Maybe also find an electrician who has experience.

Topic "KNX": Back then it seemed too expensive to me, but seeing now how much money I sank into it, I probably could have installed KNX. :-(

Cheers, bjjfan

Thank you for your answers!

That excludes each other....

I don't see it that way: a friend wired it exactly like that and implemented it with a Siemens PLC control. But since I have no idea about PLC programming, this solution is rather less an option for me.

Which system besides Raspberry is favored?

So far, I have no favored "commercial" system. I have read up on Loxone and Homematic, which come closest to my desired solution. However, I am currently hesitant to use an expensive, closed system. Raspberry gives me a very "open-minded" impression.
(For the record: I am still relatively at the beginning of my considerations)

My solution was then a star-shaped wiring from the consumers (sockets, roller shutter motors) and sensors (switches, 6-fold switches from G**a, glass break and opening sensors) to the distribution cabinet.

I am also aiming for star-shaped wiring to remain flexible in the choice of system (meaning: all lines first from the switch/sensor/detector via 24V to the control cabinet and then back with 230V to the consumer/load)

For home automation I used Homematic Wired

Did you then have to use Homematic products for the implementation? These appear rather expensive for a "wired solution". (A BuschJaeger switch costs about €6, I have not found a Homematic switch without radio so far)

It is really important that you are clear beforehand about what you want to achieve and how!

That is what I am currently working on:

I imagine the whole thing so that at first I operate everything conventionally with switches (lights, blinds, etc.) and later gradually switch to an automation solution. Hence the idea to lay patch cables/insulated bell wire to the switches and close them via 24V switching relays to use working relays for the 230V supply, in order to realize a later changeover without problems and largely without radio.

Am I that far off from a possible reality?

Since I have no idea about PLC programming, this solution is rather less an option for me.

I would stay away from a PLC. I always have in mind that I might sell the house again or have to make changes in a few years.

read into Loxone and Homematic, which come closest to my desired solution. But I’m still hesitant to use an expensive, closed system. The Raspberry gives me a very “open-minded” impression.

I also wavered between Loxone and HM. Raspberry was not an option for me. The device is not really well made and not very "trustful."
Really have a look at KNX. The costs probably won’t be that different in the end, and you have THE standard for home automation.

I am also aiming for star-shaped wiring in order to remain flexible when choosing the system (i.e., all lines first from the switch/sensor/detector via 24V into the control cabinet and then back to the consumer/load with 230V)

Good decision.
Also, lay KNX bus cables to every switch. I missed that and regret it. :-/ Now, after everything is working, I would have liked to connect the light switches directly with 24V as well.

Did you have to use Homematic products for the implementation? They seem rather expensive for a "wired solution." (A BuschJaeger switch costs about €6, I haven’t found a Homematic switch without radio so far)

I didn’t have to. But I had the choice between Loxone, HM, and KNX. HM seemed most sensible to me for my application.

For manual control of the blinds, lights, sockets, I installed a PLC switch from G**A. So in each room, I have a conventional switch for the ceiling spots and above that a 6-gang switch for the “gadgets.”

I imagine the whole thing so that initially, I control everything conventionally with switches (lights, blinds, etc.) and later gradually switch to an automation solution. Hence the idea to lay patch cables/insulated doorbell wire to the switches and close them with 24V switching relays to use work relays for the 230V supply, to realize a later upgrade easily and largely without radio.

Am I so far off from a possible reality?

Nope. You can certainly do it that way.

Just keep in mind that your intermediate solution already means effort. Bigger electrical cabinet, arrangement of hardware, wiring. It quickly becomes confusing, and in the end, you might not even want to make changes anymore because you hardly have an overview.

Cheers, torsan

Good decision.
Also put KNX bus cables in every switch right away. I neglected that and regret it. :-/ Now that everything works, I would also like to connect the light switches directly with 24V

I'm stuck here: So in addition to closing the 24V circuit, I would need additional wires to possibly be able to use KNX? How many should be planned "per switch point"?

Just keep in mind that your interim solution also involves effort. Larger electrical cabinet, arrangement of hardware, wiring. That quickly becomes confusing and in the end you might not even want to make changes anymore because you hardly have any overview left.

That can be assumed – but worse for me would be if I wanted to implement it but had missed the opportunity just because I saved 500€ on extra cables during the new construction...

Best regards,
Jens