Although the first news about intelligent systems like this have intrigued me, I have treated them as a kind of a 'toy’. I was sceptical, have nonetheless started thinking about what I would want, and have finally reached a decision. Such a system makes sense. I am, after all, building a house, in which I am going to live longer than 2-3 years. It is worth taking care of the comfort and safety. Besides, I cannot, in the 21st century, live in a home that had long ago seen its better days. If almost 50% of newly built homes in Western Europe possess such an installation nowadays, then escaping what is to come is pointless. New solutions will come as they please and they will become norm. I didn’t want the opportunity to make use of modern technology to pass by me. For the same reason I refuse to drive a car without an airbag and ABS, for the same reason I use a mobile phone, computers and fly airplanes. That is why my house should follow on and make use of modern technology.
Anteroom
I wanted the light to come on whenever I enter and it would be dark. This is simple to achieve, a motion detector is enough. It will turn the light on by itself, and will keep it on as long as I am here. After a pre-programmed time it will turn the light off. Why do I need light during daytime, however? This also won’t be a problem; the working threshold of the detector can be set to whichever level we need. I also wanted the anteroom to be warm, but I do not want to waste energy, if my kids leave the door open in the winter. And this happens quite often, as they do not usually remember such time-consuming things. No problem. The door sensor will close the water valve to the heater, if the door stays open for at least half a minute. But then I thought: 'But the heater could freeze.’ A situation like this was, however, also foreseen, and should the temperature drop below ca. 5 degrees Celsius, the valve will open just enough as not to allow the heater to freeze. Additionally, one can install a sensor to check the door lock state. Merely closing the door will be detected and signalled with a diode. Until the door had been locked, the alarm will not be turned on.
Hall
It is quite big, 3×6 metres. From here, one can move to the kitchen, the living room, the study, the toilet, the wardrobe and up the stairs to the first floor. There’s always activity here. We need switches at every door, and it would be best, that each of them would be able to control the chandelier, sconces, as well as the lighting for my collection of arms [on the walls]. I thought of installing, at each door, two dimmers and a switch. However, it turned out that all I needed was a four-key control console at each entrance. The first two keys to turn on and dim the chandelier and scones, the third one for the walls, and the fourth one to control all the lighting together, at once. Moreover, should I want to install more lighting in the future, all I had to do was reprogram the control consoles.
Kitchen
I have planned three lamps in the kitchen. Two hanging ones – one on the ceiling and another over the table, as well as a set of small lamps over the kitchen cupboards. In the window a shutter blind. Under the window parapet a heater, and a lot of electric sockets, so that I never have to shut off one appliance in order to switch another one on. The solution is to install, by the doors to the hall and the living room one control console with four buttons each. Its functions would be: switching the table lamp on and off as well as dimming it, independent control of the ceiling lamp and the cupboard lighting, switching all of the electric sockets on and off at once, as well as control over the blind. Additionally, one console could have a thermostat built in to control the heater, and the flue could have a humidity sensor nearby, in order to start the ventilator to pull any fumes out. A sensor, wired together with the temperature control and alarm system, is built into the window to check whether it is open or not.
Living room
I had thought that I would never figure out the electrics in the living room. Two chandeliers, two sets of scones, a standing lamp, the lighting of the aquarium, a small lamp behind the television set, and halogen lights for the paintings. A total of eight varieties of lighting. Of course, apart from the lamp over the aquarium and by the TV set, each of them should have a dimmer. One can enter the living room from the hall, the kitchen, the study and the terrace. In the living room I wanted to have jalousies: in the two windows on the south side, in the window on the west side, as well as in the door to the terrace. To control all this, one would only need two four-key consoles placed at each entrance to the room, as well as a remote control for convenience. The lower console would be used to control the jalousies (on the south side – both at once, and independently the jalousies in the door and the western window, and an additional key to control them all together). The second one – this was a revolution for me – was supposed to create light scenes. One starts off by imagining different typical situations that can take place. The two basic ones are: all lighting switched on, and all lighting switched off. What next? An exquisite party, a meeting with friends, an intimate dinner, rest while reading the paper, watching a movie, and observing the fish. Each of these situations calls for different lighting. It is best to make a table – in eight rows write the names of each of the scenes, and in eight columns the intensity, with which each of the lamps will be working. Example – third scene: painting lights: 100%, chandelier 1: 90%, aquarium: 90%, sconce group 1: 30%, standing lamp: 30%, chandelier 2: 20%, TV lamp and sconce group 2 are off. Lighting can be adjusted to fit any situation; the configuration may then be saved, and assigned to a key. This light scene may then be recreated by pressing just that key. One can also do this with the remote control, but I prefer to adjust with it, independently, the strength of each separate light. No problem. Of course, the living room also has temperature control and window sensors.
Control
I make use of similar functions also in my study and in the other rooms. In the bathrooms, toilets, on the terrace and staircase, the electrics will be simpler. As basic equipment everywhere we will have similar consoles, though their functions will vary greatly from room to room.
In each room, the lighting is adjusted to everyone’s individual needs. Similar jalousies and heating. Each installation is foreseen for easy and customisable user control. Sensors placed in various locations will take over various tasks of the inhabitants. Should there be too much sunlight, the light sensor will shut the blinds. The marquees will be shut should the wind sensor register too strong wind. Glass break sensors will shut the blinds should they register that a window had been broken; apart from this, the inhabitants will be notified. Motion detectors will, depending on the time of day or state of the alarm system, be used only to turn on the light or the alarm. The system will be also controlled by infrared [IR] or radio wave [RF] remotes. IR remotes find use inside the house, their range limited to the particular room where they are located, and to control the central functions. A radio wave remote can do much more, like open the gate and garage door, turn on the lighting, heating and blinds. During a summer party in the garden it can control the lamps, the fountain and decorative lighting. The receiver does not have to be located within sight. Radio waves reach further than infrared light, and they can pass through walls.
Another function, which caught my attention, is presence simulation. Available are time switches (synchronised per time signal from the radio station), random number generators and each appliance’s memory system. This equipment can control the lighting, blinds, jalousies, ventilation system, heating and other functions. When nobody is home, the system will switch the light on and off in various rooms, and the jalousies will go up or down. When the inhabitants are present, the time switch will raise the jalousies, switch on the light and control the temperature appropriately depending in the time. It will always be bright and warm there, where it should be, and in the unused rooms energy will not be wasted. Higher energy bills will be reduced. Heat does not escape through open windows, it is cooler at night, and light in the bathroom is on only when someone actually is there. Stairs and corridors are also lit automatically. When going to the toilet in the night, one will not have to search for the light switch, because the light will switch on by itself where it will be of need.
To further enhance the safety and comfort I will probably install a modem. It fulfils three functions. From any given place on Earth, at any time, I will be able to check, using a telephone, the state of the system (details like whether the windows are closed, the temperature steady and if the alarm system registers a threat or not). A few hours before arriving home I will be able to turn on the heating, raise the jalousies or open the windows. All it takes is a press of one button on a touch-tone phone. Should there be a break-in or breakdown, like a broken water pipe, the modem will call, by itself, in the first case the security company, and in the second case the neighbour, who will get a plumber.
Construction
This all seems very simple, but what kind of monstrous amount of cabling would an installation like this require? And what would happen should the computer controlling the system experience a failure or damage? As it turns out, problems like this do not exist. First of all, to control the system one needs only a single bus cable going through the house. Via this cable, all the commands and information on the form of so-called telegrams are sent. This cable will reach every control point, every spot where switches are usually placed. All the appliances are parallel connected. The cable can be split, in order to always be able to choose the simplest way. Thanks to complete separation of the control features and power supply, the latter can be simplified. Extended control functions will not require a large, multi-wire cable.
Second of all: A computer is not required. It is necessary when programming and starting the system. One of the ground rules of an KNX-Instabus system is decentralisation. Every appliance has its own microprocessor and memory. Horror scenarios about computers going haywire are out of the question. The computer performs only secondary functions, all 'intelligent’ appliances work independently. They exchange telegrams with orders, information, conditions, measured values and so on. Should any of them become damaged, this will not have any impact on the others. However, a computer, which almost everyone has, can be used in another way, for visual inspection and control. I can input the floor plans of the house into it. Additionally maybe also the external views and garden plans. On each plan, every appliance can be marked. I will be able to check quickly, what and where is functioning at a given point. With one mouse click I will be able to control and switch on and off anything I can. I heard that the whole system may be controlled via a normal TV set. I will leave that for later.
Right, but what about the costs? Just as there is no simple answer in case of traditional electrics, there is no easy way to give one precise answer here. Research shows that an intelligent installation might be cheaper than a traditional one. This depends on how many functions the system should have. In my case, the intelligent electrics have lead to lowering construction and operating costs. The balance occurs if one integrates the lighting and jalousie control with central and alarm functions. I could not stop thinking, where all those devices are to be placed? Control consoles instead of traditional switches. Sensors, depending on their function – in the assembly units in the walls, window and door frames, on the walls and on the roof, basically everywhere, where something needs to be monitored. And the whole lot of control equipment to control the blinds, heating, light, air conditioning does not have to be placed in sight. They can be mounted in a central control box, wall- or surface-mounted, or in a suspended roof.
Modification and expansion
In the future I can change anything I want. No hassle, costs, noise, wall damage and grime. I do not have to fear changes, the whole system allows for maximum flexibility. Adding new functions to the system merely requires a reprogramming of the central equipment. Reprogramming a control console allows it to be used for purposes entirely different than it was used for previously. And one more thing. In spite of the system being seemingly complex – control over it is easier than it is in case of traditional electrics. One does not have to think, what a specific button is for, they’re all signed. I do not have to be a computer or electronics professional – all the work can be done by software engineers from the company, from which I have ordered the system.
Andrzej Dubrawski
The article had been published in the March 1999 issue of 'Inteligentny dom’
Much more about KNX-based systems is to be found under www.eib.pl.