ᐅ Which Sensors for What? Inspiration

Tarnari schrieb:

that everything should, if possible, use bus cables (4 wires?)

With KNX, you don’t need bus cables running to the loads, since the actuators (at least for new installations) are installed in the distribution panel. It is important, however, to run separate phase (L) conductors from the distribution panel to as many loads as possible (including sockets). (For shading systems, you will need two anyway.) This approach also allows you to add actuators later if the initial investment should be kept low (for example, adding dimming actuators later, or similar).

Bus cables must be installed at every location where you want sensors (switches, temperature controllers, presence detectors, etc.).

Maybe I’m talking nonsense here (I'll have to double-check), but wasn’t there an option to use cables with more or fewer cores depending on the application, all of which can serve as a bus?
Then again, I might be mixing things up... as I said, electrical work isn’t really my strong suit...

Well, to avoid running a 3-core cable (L, N, PE) to each appliance, you can use 5- or 7-core cables. These have 2 or 5 phases (L) and share the neutral (N) and protective earth (PE) conductors.
With a 7-core cable, for example, you could supply and separately switch 5 devices (lights, sockets). For shading (depending on direction), however, you need 2 phases.
The KNX bus operates at 30 V direct current. Some sensors require separate power supply, while others are powered directly through the bus. In this system, black and red are used for the bus, and yellow and gray for the power supply (which seems illogical to me, but anyway). That’s why the typical KNX cable is 4-core.

RomeoZwo schrieb:

I would have liked to have those smart switches too, but I currently have four 4-button rocker switches at the living room door.

Wow, 16 buttons.

Tarnari schrieb:

1. How do you implement things with photoelectric sensors?

Just use standard photoelectric sensors. Preferably with a 30V operating voltage, so you can power them with the second pair of wires in the bus cable. The switching output goes to a binary input. You figure out the logic yourself.

For example, this is what my mailbox looks like. Of course, you could also use two magnetic contacts, but I found photoelectric sensors more precise since they only signal when there is actually something inside.

Tarnari schrieb:

2. How exactly do you do that with the slow-cooked meat?

Just use a bit of imagination. Temperatures are reported to the bus, and logic triggers matching lighting effects. You can also monitor the timing. With KNX, this is done in no time. It’s quite a niche use, but some people want it. I know someone else who has push notifications sent with the measured values from the meat. Everyone has their quirks and sometimes likes to be creative.

Tarnari schrieb:

So basically, I should try to run everything with bus cable (4 wires?) wherever possible to stay as flexible as possible? Can you control everything with it at the end? Also lights, shading, etc.?

Yes, that’s how it should be done. Run bus cable everywhere you can. I say this all the time, but people keep saying it’s unnecessary. It’s not. Later on, you end up needing the cable, as RomeoZwo shows with his awning.

RomeoZwo schrieb:

With KNX, you don't need bus cable to the loads because the actuators (at least when newly installed) are mounted in the distribution board. It’s important to run dedicated phase (L) conductors from the distribution board to as many loads (including outlets) as possible (you need two for shading anyway). That way, you can add actuators later as needed.

Well, like I just said, if the bus cable had been run everywhere, the awning would have been connected in no time. (Roller tube X-Line)

Tarnari schrieb:

But wasn’t there a possibility to use cables with more or fewer wires depending on the application, all serving as bus?
Maybe I’m mixing things up... like I said, electrical stuff is not really my specialty...

For bus cable, you should use the freely available J-Y(St)Y 2x2x0.8 cable. At that price, you can’t complain, and it’s approved for all bus applications. Sure, you could repurpose CAT or DMX cables, but why bother? If there’s no other way, then maybe consider it. But in a new build, just run the green cable everywhere and that’s it. You might use 3-4-5 rolls, but at about €35 per roll, it’s not a big deal. NYM cable has to be laid anyway, so the green bus cable next to it doesn’t matter.

Where you only really plan sensors (PIR, switches, etc.), the green cable alone is enough, as RomeoZwo already said.

RomeoZwo schrieb:

They then have 2 or 5 phases (L) that share the neutral (N) and protective earth (PE) conductors.

... as long as the 3-5 phases are protected together, preventing overload of the neutral, or the neutral conductor is properly sized.

RomeoZwo schrieb:

Black and red are used for the bus, and yellow and gray for the power supply (which seems illogical to me, but never mind). That’s why the typical KNX cable has 4 cores.

The bus and power supply from the KNX power source run over black/red. In most cases, a bus participant is connected using only these two conductors. White/yellow could be powered separately with low voltage via an additional power supply, but this is not mandatory.

Mycraft schrieb:

Well, as just mentioned, if the bus cable had been installed everywhere, the awning would have been connected in no time. (Rollotube X-Line)

If the awning had its own live wire (L) in the distribution board, it could be connected even faster to free outputs of the 20-channel switching actuator. But yes, a bus cable there would also help. By the way, the WMS UP transmitter has been ordered.