Home Automation: Overview

When planing our house I wanted to automate it at some point, so the requirements for the electric wiring tried to make it easy. Initially there was no automation at all.

I didn’t want to use a particular vendor of home automation devices like KNX, EnOcean or something else, because I am not confident that these will be available in, say twenty or more years. And also, playing around with this is more fun.

I didn’t want to use anything cloud based, if possible. And seeing that cloud based devices might get bricked over night, because the vendor is bankrupt or doesn’t want to continue the service, just proved to me, that using cloud based services is not a good idea. But there is some cloud usage which I couldn’t avoid (so far at least).

My home automation consists of several building blocks:

  • Electric wiring: Lights, roller shutters, switches, etc.
  • openHAB: This is the core and glues everything together
  • WAGO: A wago i/o system interfaces with switches, lights and roller shutters
  • Velux KLF 200: A velux device to interface with my roof windows
  • Hue bridge: The hue bridge interface to interface with lights; currently only the kitchen light
  • Nibe: My heating uploads data to nibe and openhab can download them; no direct connection
  • Tasmota: Various wireless plug sockets to control some devices; all flashed with tasmota to not use cloud services
  • Alexa: The alexa devices interface with myopenhab.org to control the local openhab instance
  • Roborock: Vacuum cleaner; interfaces with openhab
  • Samsung TV: Some control, mostly unused
  • Onkyo A/V-Receiver

Overview

This is an overview how the various parts are connected to openhab. The next chapters explain these in more detail.

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Basic Electric Wiring

Lights

Usually electric wiring in a house is done like this (well it is simplied, I left out all the details of grounding, fuses, etc):

2 3 0 V S w i t c h L i g h t

The switch is somewhere in the room where the light is and power is connected to it.

But I think this is hard to automate, I would have to replace all switches or lights with something else and find a way to transfer a signal to it (e.g. wireless or a bus). That is the standard way to automate a home, but I thought: it should be easier :)

We did it differently:

2 4 V L P a u t s c h h i b n u g t t s o w n i t 2 c 3 h 0 V L i g h t

We use a low-voltage control system with a push button (in the room) and a latching switch (centrally in the fuse box). The latching switch then turns on or off the light when the push button is pushed.

These are some of the latching switches:

In total there are 31.

The upside is: it is purely electric and latching switches are very robust and well-working.

The downside of this approach: a lot more cables are needed, because now several 230V wires need to go into a room: a pair for each controllable group of lights. We have a few spare wires if we ever want to break up a group of lights. The push buttons use very thin wires (bell wire) and quite a lot are needed, too. The sockets for the push buttons are very cramped.

If several push buttons for the same light group are needed, they are just added in parallel:

2 4 V L P P a u u t s s c h h h i b b n u u g t t t t s o o w n n i t 2 c 3 h 0 V L i g h t

Roller shutters

An electric roller shutter has a motor and they can go up or down; they will automatically stop at their end position.

Classic wiring:

2 3 0 V U D p o w n M o t o r

A special switch makes mechanically sure that the Up and Down switch can never be turned on at the same time. I think if power is given to the up and down input of the motor at the same time, the motor will be damaged.

With our 24V control this wiring looks like this:

2 4 V U D p o w n R R e e l l a a y y 2 3 0 V M o t o r

The relays (in the fuse box) are just there to switch the control 24V to the needed 230V for the motors. The relays could both be triggered and the motor damaged, just the mechanical switch make sure that this won’t happen.

On the left are the relays for the roller shutters (J = Jalousie) for up (A = Auf/Up) and down (Z = Zu/Down). On the right are the relays for the valves of the floor heating (V = Ventil/Valve). The valves are not part of the home automation; there are simple mechanical temperature sensors in each room that tell the relays to open or close and motors will open or close the valves very very slowly.

This is mostly the basic wiring before adding home automation.

Next

Next chapter is about my usage of a WAGO