Domotics/home automation Manual

November 20, 2017
home automation control systems architecture

This is a collection of articles on the topic of Home Automation written in Serbian by me for my (now defunct) company Cubo Control. Our friends from The Centre for Architecture Belgrade published this manual as a series of texts on the topic and they were kind to translate it in english.

This is the series of texts on this topic, published by The Centre for Architecture Belgrade in cooperation with Cubo Control company form Belgrade. A comprehensive overview of domotics is prepared by Radiša Jovanović, PhD. and Marko Aleksendrić, PhD. They are experienced mechanical engineers, whose field of expertise covers programming and design work, through intertwining of various technologies.

Domotics

Is it time for the house to finally become a machine?

Contemporary home is filled with various electronic devices, that pile-up in time and become more and more important in our lives, taking over more and more functions. Ergo, they become smart. This does not apply only to the devices usually considered smart – from computers to telephones, but also to those that exist in our home for a long time already – you probably don’t know what your new TV can do.

We are slowly getting used to networking these smart devices, allowing them to communicate amongst themselves – as it eases our work, as well as enjoying in music or movies. But what if we wish to go a step further and network and automatize other parts of the house?

For, the house is a machine for living. Technological development enabled us to consider using advanced systems for management of lighting, heating and cooling, surveillance and security, shading… Your home won’t have a teleport, moving walls and hologram projectors any time soon, but many everyday activities will surely be much easier to do.

What is home automation/domotics?

It is very hard to define an area which is developing and changing so fast as domotics. Like for some other similarly dynamic fields (IT and others), the available information is often incomplete, not up-to-date or completely wrong. The additional problem is the absence of a uniform standard, together with the need to present it to the client, who is, by definition, focused entirely on costs, neglecting almost completely the technical aspects, such as communications protocol and others.

This series of articles is the result of an effort to create a panoramic overview of the field of domotics which would give the reader (architect, engineer or client) the notion of the basic concepts of technology. Getting to know the principles and technical possibilities of this technology, should help clients through the plethora of available products, but also with the evaluation of the different suppliers.

We shall try to present the overview and short history of domotics, with specifics and differences from the traditional home systems, we shall briefly describe the communications network, the architecture of the connection routes and basics of the communication protocol. In the final parts we shall focus on the European standard KNX-the architecture, the devices and system configuration. Domotics- the smart home concept

The needs of the modern homeowners are constantly changing and are undergoing a process of evolution, following the rapid technological advances, especially in the past ten years. Before we look back at the technology itself, we should tale a look at the way homes have been changing- during medieval times, home were almost completely empty, with rare pieces of furniture, while today, it is very hard to find adequate space for any new object, even in big apartments, especially of they are some type of electrical equipment- there are power and communication chords, modems, routers, decoders, sound systems and others.


Parallel to the introduction of the modern lifestyle is the transformation of the traditional electrical appliances into complex integrated systems, primarily thanks to the introduction of the electronic components.

Such integration brings about radical changes to the concept of a device or system- the information canal is separated form the actuator, therefore the data obtained form one sensor are no longer pertinent to the originating device, but are shared within the whole network (of the apartment or the building).

This transformation of the logic of the system enabled the possibility to eliminate the isolation of individual devices and subsystems installed in the building and opened the possibility to have new functionality, which would be unthinkable if we should rely solely on the traditional technology.

The demands of the space users are constantly growing, but so are the specifications of the new buildings, primarily for environmental, energy consumption and security reasons. The regulations relative to property construction and design of different built-in systems aim to reduce pollution, rationalize the use of energy and it is clear that to meet these demands we have to introduce the intelligent space, capable of controlling the comfort (defined and quantified in a certain, prescribed way), guaranteeing safety, low energy consumption and meeting the need of the elderly or other groups.

The very term that we prefer, domotics, comes from French neologism domotique, in fact derived from Latin word domus (house, building, home) and French automatique (system control) and is literally translated as the automated home. Besides this term, the common nomenclature is smart house, smart home and home automation.

To put it simply, domotics is the area that studies the technology designed to improve the quality of life, enable the communication between the traditional subsystems already installed in the building and the new components, with the aim of achieving new, modern functionalities. What lies in the base of this multidisciplinary field is the ability to connect electrical wiring, electronic systems, heating, ventilation and air conditioning, alarm systems, fire alarm systems, multimedia, space detection, control of windows and shades and similar systems.

A building with such integrated system enables the control through adapted interface (switches, touch screens, remote controls, speech recognition, biometrics and others) via a computer unit that can be with central or divided functionality. Different components of the system are interconnected and connected to the control system through different types of connections (for example by BUS). Such system enables the execution of user commands (from simple ones, like switching on or off the lights, opening or closing of shades, up to the complex scenarios conditioned by the weather, the user identity etc.), the constant monitoring of variables such as the temperature, humidity, energy consumption and others, the automated regulation of parameters, as well as sending certain signals of necessary, and providing remote control services. The systems are usually able to inform the user via audiovisual signal (LED diode on the switches, graphic elements on the touch screens or tablet computers, sound signals), and there is also a possibility to communicate with the system through the Internet protocol, the text messages or email.

If the concept of domotics is raised to a higher level- the level of the whole building, we talk about the so-called Building Automation, or the automation of a building creating a smart building, with modern technologies being able to control the technological installments (air conditioning, heating, ventilation, water, gas and energy distribution, security systems), information networks in order to provide flexibility, comfort and high standard of living and working in such a building. Unlike domotics, building automation is much more mature and with a standardized, stable offer and demand, and we will discuss it later in detail.

It is important to emphasize that domotics is no longer a discipline reserved for researchers or scientists; today it is available for wide variety of users, although they might require some support.

The current situation in this field, according to many studies from countries of Western Europe, the USA and Australia is specific: many potential users of smart spaces are instinctively drawn to modern solutions, but very often, after some consideration, conclude that is unnecessary and give it up. This is a very important aspect, definitely confirmed by all studies and research performed in the past ten years – a poorly informed end-user, but also architect and contractor, is a major obstacle. Logically, the first and most important step in overcoming this problem is the right information about advantages and disadvantages and specifics of domotics solutions. This is also the main goal of these articles.

The engineers themselves, unfortunately, are not of great help with this problem; usually they have met or been trained to work with only one type of equipment of one of the manufacturers, which imposes limited solutions and diverts them from considering other possibilities. Since one of the main goals of domotics in the future period is to make a technological standardization, but also to standardize everything else within the four walls (offices, hotels, flats, companies, schools), it is clear that all factors on the market should enable, though their goals and interests, above all the adequate valuation of the field.

Domotics and Traditional Systems

The essential difference between a traditional electrical installation and a domotic system lies, above all, in the degree of integration. It is possible to achieve certain functionality even with the traditional systems, but solely using separate components, without any true integration. The coordination of such subsystems usually implies unacceptable costs, but also a low level of efficiency, as well as safety and comfort.

Figure 2.1: traditional installation system

On the other hand, domotic systems are designed to satisfy different functionalities, and most importantly, to be able to interact between different components. An example of that is a simple presence detector which works on the principle of infrared radiation (PIR sensor) which, in a traditional system, has a limited function when the alarm is on, while it can also be used in an intelligent system as a motion detector when the alarm is off, and can perform such functions as opening doors, turning on the lights and other. Certain infrared sensors can measure the light in the room and can also be programmed to turn the lights on if it is dark.

In a classic electrical installation a physical circuit connects a switch or a button directly to the powerline, for example, the light. This means that each variation in the power consumption or the subsequent addition of functionality requires some changes in the system of power cables. In an integrated system, on the other hand, a logical circuit converts an event, like pressing a button, sends a signal to a single or a group of actuators, that perform the action, such as turning on the light.

Basically, every interaction between the user of the space (via a domotic system) – whether it is direct, like pressing a button on a wall or on a panel, or indirect, such as entering a room or a change in the temperature due to an open window, could activate one or more actions (scenarios). In this way the connection between the events and the subsequent action is no longer limited to the physical cable between the devices, but solely to the information that the devices exchange.

Figure 2.2 Domotics system- separation between the powerline and the information channel

The separation of information from the action could seem unnecessary – in case of controlling only one light we need two devices instead of one, but if you look at a complex system with more appliances, the situation changes drastically. Also, to add functionality (to a device) there is no need for a change in the existing cables, but generally it is sufficient just to change the system’s programme. Due to this fact, it is advisable to design a system bearing in mind the possibility of such upgrades.

Figure 2.3- Difference between a traditional switch and an actuator

Comparative analysis of domotic and traditional systems

ADVANTAGES

Traditional system
Domotics

DISADVANTAGES

Traditional system
Domotics

Why Couldn’t an Electrician Do It?

The architects and contractors most commonly look for electricians when they consider installing a domotic system. However, a vast majority of electricians just isn’t able to design, integrate or program intelligent home automation systems.

The electricians, especially the old-school type, are simply not qualified to configure distributed audio, to get the maximum out of the video system, ventilation system or to understand the sophisticated software that controls the entire house system. To entrust an unqualified person with a home automation system is far more serious than to get the neighbor’s boy to repair your laptop or to let your cousin redesign your home, just because she is good with colors.

Expensive Mistakes

And while we have already analyzed the advantages of domotic systems, the price you pay if the system is not configured properly, is steep. The complexity of integrating so many different systems creates many potential problems:

The system does not work properly. A badly designed or integrated system will not function properly and in many cases even the homeowners’ safety may be compromised.

There is no true integration. A well-integrated system requires a minimum of control devices and units. The presence of many control units mounted on the wall is a clear sign of sub-par integration. The control must be intuitive and straightforward.

Deadlines not met and cost blow-outs. Bearing in mind that so many contractors need to be coordinated, even the slightest mistake in project management can lead to costly delays.

Compromised aesthetics. A smart home cannot look like an electronic showroom – the components need to be seamlessly integrated into the space aesthetics.

To work with a domotics designer is not much different from working with an interior designer, an architect or any other similar professional. It is a person able to identify the client’s desires and needs, analyze the building’s plans, design a detailed solution for a domotic system and recommend the best equipment. In order to achieve the optimal results the domotic system should be designed and programmed by an expert in home automation. The process does not end with programming the control software and integrating properly all the devices, but it also has to ensure that all the client’s aesthetic and environmental criteria are met.

The procedure

The following part will explain the most commonly accepted procedure of designing and installing a domotic system into home and business spaces.

Defining the Scope of Works

Defining the scope lies in foundations of any successful home automation project. Seeing that domotics is a relatively new and unexplored area, the investors and homeowners are often unable to see the advantages of the newest technology. It is necessary to lay down the system performance in different fields. A domotic system designer should present the client with all the possibilities, starting from the requirements, but not stopping there. After presenting all the possibilities to the investors, a detailed specification needs to be prepared, including the available budget, space aesthetics, functionality, energy efficiency and future technological needs.

It is of the utmost importance to separate from the beginning the costs of installation and of the system itself from the costs of electronic components (local network, audio in all the rooms, home cinema and similar).

Design and Documentation

The design and documentation requires a close cooperation between client, architect, contractor, interior designer and other people involved in order to produce documents that meet the needs of all parties involved. This is obviously a critical phase in which projects often become stuck.

A domotic system designer goes from room to room and thoroughly discusses the possibilities with the interior designer, the architect and the client. Only then the functionality of each room becomes fully defined and adequate electronic equipment can be suggested, to meet the designed criteria. All systems of the building need to be involved in such detailed planning-plumbing, heating and air-conditioning systems, interior design and others, in order to lay out properly the electronic infrastructure and control devices.

This should finally result in a set of documents that includes:

The existence of such unique documentation is often essential, in order to avoid many problems that may arise if the designers work with different specifications.

Selecting an Electrical Contractor and Cable Layouts

The selection of an electrical contractor will depend mainly on the specification designed in the previous stage, all the more reason to make the specification as precise as possible. Previous experience is necessary and the ability to perform the specified work.

If the documentation is well-prepared, the electrical contractor will proceed to install the infrastructure: electrical, lighting, audio and video, communications and data cabling.

Project Management

When building a smart space, a vital factor is an open communication between different parties involved, since it is a complex process in which every step needs to be monitored.

The Choice of Components and Products

The final choice of certain components is usually made by the owner of the space during the construction – the choice of an audio and video system, the security system and others. At this stage we can define the final costs of these subsystems, although the components themselves are often bought at the very end. This enables the client to buy the newest systems, preferably at a lower cost, but also to get a much clearer idea of the specifications of the components used in his space (the screen size, number of control units, position of the speakers and similar).

When the final choice is made, the components are bought and installed and at this stage the space is ready for handover.

Handover and Tuition

When all the components are installed and programmed, the space is ready. The home automation designer explains how to operate the finished system. Since the essence of a well-designed place is simplicity, this should not be too demanding. A properly designed system is intuitive and the user should need a brief period to adjustment. You should also allow some time for fine-tuning, in which the designer may return during the following weeks to refine the system to meet the client’s needs.

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