Mycraft
2019-02-02 15:05:20
- #1
This is what the builders ask themselves:
- Do I need this now or not?
- Are the additional costs justified?
- What are the advantages?
- Where are the limits?
- What is smart home anyway?
For this reason, I would like to share some of my experiences.
I have been living in an automated house with modern electrical systems for about 7 years. Whether it is smart, automatic, or intelligent – that is up to the reader to decide. I will show examples later on of how we implemented this or that to give an idea of what is possible. I would like to say that I would classify our house as rather less/mid-level automated, since I know examples where much more has been done.
Smart home/Modern electrical systems/Intelligent houses — all these terms somehow describe something, but everyone imagines completely different things. Especially if you have no background and never knew anything else than: clap the switch -> light on!
Every manufacturer who currently offers just switchable sockets, motion detectors, and possibly thermostats with a central control does not hesitate to call it a smart home.
But fundamentally, none of this is actually smart. At most, it just slightly eases everyday life.
Because sockets with timers, lights with motion detectors, and heating that maintains or automatically lowers/raises the temperature are simply three different systems, which can coexist alongside each other with a central control and perform their tasks. These helpers also existed 30 years ago, but back then, nobody called that smart home.
Adding a voice assistant still does not make it a smart home.
If you close both eyes, you could call it an automatic house.
Smart homes — meaning “clever” or intelligent houses — are much more.
"It becomes intelligent when a variety of systems/devices from different manufacturers are united, the processes interact, and synergies arise."
The functions can and must be individually adapted to the specific needs and habits of the owners/homeowners and also take the environment and environmental influences into account. All this, of course, economically and always flexibly expandable and modifiable.
Seven years ago, we also faced the decision and considered back and forth which system to choose.
What was important to us:
- No closed solutions, i.e., no forced manufacturer or cloud issues
- Availability and variety of components
- Flexibility and expandability
- No batteries and additional plugs
- High reliability
- Future-proofness
- Possibility for multiple systems to work with each other, not just alongside/opposing each other
- Cost
Particularly important to us was inconspicuousness. We wanted the technology but wanted it to be as invisible as possible. It is understandable that displays, switches, presence detectors, etc., are more noticeable than normal light switches, but the rest of the system cannot be seen. There is nothing additional except the end devices at the sockets. No glued or screwed sensors on the windows or doors.
Everything was realized with KNX by a capable specialist company and myself.
The house currently has:
- approx. 100 sockets, about 30% of which are individually switchable
- 48 switchable channels in total
- 15 light groups, 8 of which are dimmable
- 14 roller shutters
- 2 built-in touchscreens and other portable devices (laptop, iPhone) for control
- Various temperature, gas, CO2, air quality, and light sensors
- 8 presence detectors
- 8 push buttons with display, each with 3 rockers (6 buttons)
- 10 smoke detectors
- 30 LAN sockets
- 8 IP cameras
- 8x SAT (3 TVs)
- 1x voice control
- 1x weather station
Examples of our automation:
Shading/Climate/Ventilation and Heating Control
To prevent a house from overheating in summer while still absorbing as much solar energy as possible, cooperation of these systems is needed.
The heating detects from measured temperatures inside the house that heating is not necessary and circulates water in the floor to (slightly) maintain the temperature, because the weather station reports: It will be a warm day today. The temperature sensors inside and outside notice the difference and adjust the ventilation system so that air exchange is guaranteed but remains dynamic, and in case of sudden air contamination (e.g., cooking), odors are quickly filtered out, but only a minimum amount of warm air from outside is drawn in. The ventilation system detects impurities in the air and decides independently what to do.
The shading constantly adjusts the slats of the roller shutters to keep heat gain in the house as low as possible but without darkening the rooms to avoid disturbing the residents. Here the weather station reports the current solar intensity on the façade sides facing the sun. As a final measure, the air conditioning is always on standby and cools the rooms if the thermostats indicate a need. If windows/doors are open for longer, the air conditioning switches off. The required hot water is heated and stored by the solar system.
When absent, or if the residents take a nap, it is maximally shaded/darkened and minimally ventilated. The other systems remain unaffected and continue to maintain temperature, etc., at the desired level. Presence and absence, sleep are detected by additional sensors and reported to the systems.
In winter, everything works the other way around. There is hardly any shading because the house tries to capture as much "free energy" from the sun as possible. Ventilation is constantly adjusted to conditions. Windows generally remain closed. The air conditioning stays off as does the summer bypass.
When you shower, the systems also notice and increase exhaust to quickly transport away moisture.
The system is tuned well enough that we can (and want to) forego the ERR. To a large extent, however, this is simply due to the outside temperature controlled boiler and the self-regulating effect, not the additional control.
Roller Shutter Control:
As mentioned, shading is controlled. In addition, there are different scenarios, which are usually executed automatically and can also be manually triggered.
The roller shutters are constantly informed by other sensors about what is currently happening. For example, solar intensity, window status open/closed/tilted, temperatures inside and outside, and whether someone is home. From this, the roller shutters calculate which position is currently appropriate.
For instance, roller shutters go up in the morning and down in the evening. It is not enough that it is simply dark/light outside. The time of day and the season must also be right. In winter, some roller shutters remain open for several hours longer in the evening because of Christmas lighting on the windows. They then close when the residents decide to go to bed.
There is of course an additional safety mechanism at the patio door. As long as it is open, the roller shutter remains up. Generally, when someone opens a window, the roller shutter goes up. Windows closed -> down again unless it is already light again, etc., or shading mode is activated, then the current used position is approached. If you want to close the door but still stay outside longer than the preset delay, another condition applies: As long as the terrace light is on, the roller shutter remains up. This way, the chance of locking yourself out is zero.
The advantage: You don’t have to worry about the roller shutters. They are always in the correct position and require no human intervention. However, if a person wants something else, like going out on the terrace while the roller shutter is closed, just open the door.
Light and Shadow:
Presence detectors are installed in all non-living areas, i.e., kitchen, bathroom, hallways, etc. These switch the lights on or off slowly or quickly as needed. It depends on what is going on and what kind of light is needed. It also constantly measures the current conditions and whether light is needed at all. Different rules apply during the day than at evening/night. Thus the brightness of the lighting is adjusted. The house also "knows" through sensors when people sleep and when not, so in the morning the light is only dimly switched on. Additionally, roller shutters in bedrooms stay down until a certain time if someone sleeps, and the doorbell is deactivated during that time.
Here one sees again that everything works together.
Because we have two cats, unfortunately, we could not automate everything even more and had to forgo the popular presence detector under the bed, for example.
Furthermore, we have lighting scenes such as cinema, dinner, TV, etc. Here, lighting moods are created according to our preferences, e.g., the house darkens when the projector is turned on, or the subtle LED lighting turns on while watching TV.
Rooms like hall, foyer, utility room, guest WC have small push buttons (light switches). Everything works automatically here as well; guests handle it wonderfully and you hardly ever need to explain anything.
Gimmicks:
Since much becomes possible through the extended electrical system, we also have various little things that would not even be conceivable with conventional wiring. For example, a post recognition sensor in the mailbox that reports as soon as something is inside. Also, the coffee machine turns on by itself downstairs in the kitchen in the morning (defined time period) after waking up and makes fresh coffee alone.
Other small things:
- Presence simulation (a daily routine is simulated, not just dumb on/off of lights, etc.)
- Alarm system (which makes the house flash wildly in case of alarm, etc.)
- Motion alarms and doorbell events to the phones
- Motorized lock
- Garden irrigation
- Central on/off (in several places in the house and online)
- Various statistics and graphical representations of temperature trends etc.
- Consumption measurements
- Leak detector
- Power consumption of individual sockets with smaller logics
- Trash calendar with notification of the respective bin the day before
- Visualization of the system and access from outside
etc.
Why all this? Well, the reasons are diverse. First and foremost, it saves a bit of time. You don’t have to operate the light switch or roller shutters. It just makes life a bit more comfortable. You don’t have to check five things to watch a movie but simply turn it on and the house takes care of the rest.
It also gives some (perceived) safety through status messages on the phone or presence simulation. Of course, you also save some operating costs, which are of course eaten up by even more sensors and devices. Because appetite grows while eating, and you keep expanding the systems because you missed one function or another.
By the way, our system with about 80 participants/devices consumes a lean 20W of power. But there is no end in sight; I bought myself a home server for Christmas. Until now, a Raspberry Pi was working as a gateway to the outside world and visualization.
I have certainly forgotten some things, but that was enough text now, don’t you think?
Here are a few pictures for relaxation: