ᐅ Open Smart Home System "Prototype for Everyone"

Created on: 27 Aug 2020 10:48
K
knalltüte
Background:

I own an old house (about 270 years old) where my company and my apartment were located. As the office kept expanding with new employees being hired, I moved into a separate apartment due to space constraints.

However, this was not meant to be permanent. I wanted to have something of my own again, but this time “small but nice.”

After considering various options from tiny houses to mini houses, the decision was made to build a small semi-detached house and use one unit myself (about 65m² (700 sq ft) plus terrace and garden).

My brother is building the other semi-detached house, and both units will then be rented out.
High-quality, ecological, and sustainable construction was important to us from the start. A healthy indoor climate, photovoltaic system, heat pump, and controlled residential ventilation were therefore fixed requirements.

At first, I considered some home automation (implemented, for example, with Shelly devices installed later to control certain functions remotely).

But since our company is involved not only in general IT activities but also in software development, programming, and consulting on IT infrastructure and digitalization for larger organizations such as hospitals, and since my brother is the lead developer of a software that has been on the market for over 20 years and is the market leader in Germany in this field…

Couldn’t we do it ourselves?

Yes, we could!

“Coincidentally,” a bachelor thesis on an open (non-proprietary) smart home system was submitted to my brother (who teaches computer science at FOM among other things).

Based on this and other work that proved certain fundamentals, plus freely available information showing many other possibilities of a smart home, we formulated our requirements.

We wanted a “Smart Home” (as we understood it at the time).
We wanted to at least control lighting and blinds, have a front door with motorized lock, possibly video intercom systems, presence monitoring, etc. The wishes naturally grew as we learned what was possible. So, voice control via, for example, Alexa should also be possible (for those who find it useful).

Our key criteria were:
• Open system (no proprietary/cloud dependencies, etc.)
• All active components centralized in the distribution board if possible
• No “bus switches,” but “normal” Gira, Jung, etc. push buttons
• Affordable!
• The base programming can be quite complex (done by experts), but afterwards the system should be adjustable by “non-technical users” via a GUI (This alone could lead to lengthy discussions)
• We will do the wiring and programming ourselves (my brother and one of our partners are software developers, and I am an IT specialist)
• The wiring will be done with plenty of spare capacity and smart home compatibility.
-> Lighting circuits (lamps) all go directly to the distribution board
-> Outlets are wired room-wise to the distribution board and use 5-wire/three-phase cables so nearly any outlet can be switched later with small wiring adjustments.
-> All push buttons are connected with (plenty of) LAN cable directly to the distribution board
(Discussion about CAT7a/CAT8.x LAN cabling or 10DA took place: Result: Almost everything will be done as CAT7A duplex because, overall, it is easier to handle and cheaper for us.)

The result will soon be installed as a prototype in my unit (half a semi-detached house, about 65m² (700 sq ft)). The photo of the small sub-distribution board is only a small part of the test system currently being assembled! The Eltakos were installed only for comparison (space requirements vs. the Controllino) and will probably not be used in the finished system.

Almost anything “speaking” a smart home language can be integrated into the system via the appropriate binding.

The core hardware (the “brain” of the system) will cost about 1000 to 1500 euros (approximately $1100 to $1650). It mainly consists of the SmartHome Manager (Raspberry Pi) and Controllino Mega pure (Arduino).

The programming of OpenHub, etc. (open source) is done by our software developers/programmers.

Temperature, distance meters, motion detectors, humidity, CO2 sensors, and similar devices can easily be integrated. Small touchscreens (around 20€ (about $22)) as “cornerstone components” usually cost only a few euros.

I will be happy to report on further steps and on the prototype development once progress continues.

Notes:

The advantages of KNX are often mentioned, and some of these certainly apply. In our smart home, if the SmartHome Manager (which is also industrial hardware) fails, almost nothing works. With KNX, all unaffected subsystems continue to run. However, the example described by @Mycraft: “… It’s enough to just connect another push button to the bus cable and configure it…” is hardly feasible in practice. The user cannot do it themselves, the proverbial “unicorn” (ideal technician) is not there, and if the “system integrator” does come eventually, every small change or adjustment is extremely expensive. (These are the experiences of two people with KNX in our circle of acquaintances.)

Please do not fill this thread with pros and cons of the various systems. It only concerns “our” system based on the hardware and software components mentioned at the beginning – thanks!
H
hampshire
2 Sep 2020 21:25
untergasse43 schrieb:

That thing looks to me like one of many already existing cheap DIY solutions.

It doesn’t seem that way to me. I am interested in technology and functionality. The fact that we are very aware of this and, despite our fascination, have decided against smart home applications is a different matter altogether.
untergasse432 Sep 2020 21:30
Maybe omit the word "cheap." I’m really curious about what additional software will be developed and how to set it up from scratch. Then we can continue discussing whether it is a "DIY solution" or not.
T
Tassimat
3 Sep 2020 08:47
hampshire schrieb:

It doesn’t look like that to me. I’m interested in technology and functionality. That we are fully aware ourselves and have decided against smart home applications despite their appeal is a different matter altogether.

I completely agree. We also consciously chose not to use smart home technology.

I find it very reassuring that my conventional electrical system simply works and will never require updates or maintenance from me.

But at some point, Shelly devices will be installed.
superzapp schrieb:

Just give us a little more time before tearing the project apart… okay?

@superzapp I don’t think anyone wants to tear the project apart hastily here. We’re just extremely curious about how you implement various details. The only thing that has been thoroughly criticized is the blockchain, and rightly so.

Speaking of blockchain: @Ben-man I still don’t see the benefit of a blockchain. Why would a door, switch, lamp, etc., need to know the entire data history of a blockchain? What advantage does it have over a conventional digital signature for control commands?
B
Ben-man
3 Sep 2020 09:38
Tassimat schrieb:

Speaking of blockchain: @Ben-man I still don’t see the advantage of blockchain. Why does a door, switch, lamp, etc., always need to know the history of data on a blockchain? What is the benefit compared to a conventional digital signature of control commands?

I don’t know, I already wrote that blockchain is not just about keeping a history. Nothing is mandatory; there are many ways to achieve the goal.
Mycraft3 Sep 2020 10:28
Tassimat schrieb:

I find it really reassuring that my traditional electrical system will simply work and will never require updates or maintenance from me.

Here is the same, but with modern electrical systems. I find it equally reassuring that it will always work and never ask for maintenance or updates. But you don’t have to press any buttons anymore, and everything can be changed from the sofa at any time.
Tassimat schrieb:

Eventually, Shellys will be installed anyway.

I thought there would be no maintenance or updates? You are contradicting yourself.
untergasse433 Sep 2020 10:31
Tassimat schrieb:

I find it very reassuring that my conventional electrical system will simply work and never require updates or maintenance from me.

Eventually, though, Shelly devices will be installed.

That contradicts itself. If a security vulnerability appears in the Shelly devices or a protocol becomes exploitable, you will have to update them. Especially with Shelly devices, it’s important to regularly check the firmware changelogs. They are definitely not error-free.
On the other hand, I know numerous KNX systems that have run flawlessly for over 10 or almost 20 years without any "intervention." KNX, to stay with the example, is indeed old and comparatively slow, but also incredibly robust. Current competitors still have to match that kind of lifespan. Of course, if everything is moved to IP and servers come into play, which are even online at the end, you might also need to take care of maintenance there.