1) Introduction: what is meant by home automation
Home automation is a new way of conceiving and designing domestic systems.
Home automation is the result of an evolution of technological systems: in the houses of the past the systems were mainly made up of a light point and therefore a home automation system would have been useless. But with the passage of time and following improvements in the plant and technological fields (automatic shutters, air conditioning systems, burglar alarms, video surveillance methods, audio systems…) it has been possible to introduce the use of home automation.
The most particular aspect is interdisciplinarity, because the topic in question deals with very different themes, from networks to security systems, lighting, air conditioning and even photovoltaics. The problem is to understand all these different aspects and merge them into a single system: home automation as a technique is based on this operation; in fact today more and more credit and importance is given to the professional figure of the system integrator, who is in charge of the home automation system.
The term home automation alludes to a "computer house", which can be managed using technological tools.
On a technical level, home automation is a digital system for managing domestic systems. Check all systems: electrical, air conditioning, security, acoustic, lighting, etc. . The characteristics that distinguish a home automation system are control, integration and digitization. Control since the system itself has no autonomous function, it is simply independent. The integration allows the different subsystems to communicate with each other; finally, digitization allows the various systems to interact in the form of bits.
2) Costs, advantages and problems of the home automation system
Home automation therefore appears to be something well defined and brings numerous benefits. For example, it allows you to rationalize energy consumption related to electricity and gas, increases the safety of the electrical system and of the entire house, and overall allows you to give an active response to any emergencies, allows an improvement in comfort, through control centralized and not of the plant in all its subsystems, through computer control via the internet.
In the past, each device had its own remote control and this created a lot of confusion. Home automation avoids these problems also thanks to the increasing use of tablets and smartphones through which everything can be controlled. In this way everything is more easily and rationally managed.
The system is easy to use and is not dangerous. It always works, even in the presence of any faults, and is immune to malfunctions.
Of course, the costs are not to be underestimated, since it is necessary to consider how much the home automation system affects the total cost of the systems. There are various methods with which a home automation system can be created. For example, a system that is limited to the control of lights and loads (basic level) has an impact of about 10-20%; if the plant is larger, the cost will also be higher. The cost also changes depending on the type of system adopted, since there are various technologies to create a home automation system. A complete system within a standard 120 sq m apartment can account for up to 50% of the total cost.
3) General structure of a home automation system
A home automation system always consists of three elements:
- commands: transmit the order to perform an action, such as buttons to turn on a lamp;
- actuators: perform a specific function, such as turning on a light;
- transmission means: these are physical means by which orders pass from the command to the actuator.
The commands play the fundamental role of direct control, since most functions are set through a command configuration. Some systems simply use home automation buttons, while others still employ specific interfaces that use traditional buttons to transform them into home automation buttons. Today, keyboards with touch technologies are used, which also have a design more suitable for many modern homes. But in addition to an aesthetic reason, the use of keypads is preferable to traditional buttons as they allow better programming and integration of functions.
Actuators are also called outputs; many of these have more complex functions than simply switching on a light bulb. They are distinguished according to the function they perform:
- digital actuators are used mostly to manage lights;
- the dimmer actuators have the task of regulating the luminous intensity of the light points;
- the shutter / venetian blind actuators control the motors of the shutters; analogue actuators direct current intensity, but are mainly used for industrial buildings; special function actuators are specifically designed to perform particular functions, such as an actuator that sends infrared to another device.
The transmission means guarantee communication between controls and actuators. There are three transmission media: - a cable that allows communication between the home automation components; - radio waves; - an electric power cable. The most used method is the data transmission cable, called BUS cable. The different components of the system are not all located on a single circuit but are physically distant from each other and connected by a single channel that puts them in communication.
Block diagram of the functioning of the HOME AUTOMATION CONTROLLERS network
(diagram taken from the website www.domoticadesign.it)
4) Design of a home automation system
When the home automation system is complex and composed of several mini-systems, we can speak of a hierarchical structure. For example, if the air conditioning system is inserted into a digital system which in turn also controls the lights, we are dealing with a system of this type. An advantage of these structures is that the various systems are created in both hardware and software, and therefore the mechanism is faster in processing information, but also more efficient and less expensive.
In defining a system, it is necessary to take into account the individual systems and their characteristics, establish the home automation systems and higher supervision systems, but also understand the required performance. There may be two different conditions: the creation of a new home automation system, or the transformation of an existing system, integrating the different systems together.
To design a home automation system in the best possible way, some specific professional figures must be involved immediately: - the designer of the electrical systems, the designer of the mechanical systems, the designer of the structures and the designer of the architectural works.
The integration of the systems into the structure is fundamental, since the goal is to make the different systems compatible with each other. An integrated system first of all provides for coordination between the system designer and the architectural one, in order to use some elements of the building to be able to create ground systems, to define the most suitable spaces for passing the electrical and water pipes ..., to find the most suitable spaces for technical rooms.
The design of a home automation system consists of several phases:
1) survey on user needs
2) forecast of the plants required
3) definition of functions
4) control system selection
5) study of the systems diagrams with the drafting of signals, commands and connections
6) analysis of the specific structures of the system
In the very first phase it is necessary to analyze the characteristics of the place, the type of building (single house, condominium, size of the premises) and understand the real needs of users. It turns out to be an important phase because following this evaluation it is clear if an installation of some elements is necessary or if it is preferable to study a certain type of system instead of another.
The second point involves an evaluation of the systems, and then deciding all the systems to be installed. In this way, the different operations of the systems are studied, such as the motorization of gates, shutters, doors and windows, ... and this analysis has the task of highlighting the various possible ways to control the devices present and avoid inconsistencies between the numerous systems. Of course, the positioning of the control devices must be made based on the proximity of the user and the distance between the load and the actuator must be minimal.
We then move on to the definition of the functions, that is, we choose the operating modes of the security systems, air conditioning, lighting, door, window motorization ..., acoustics, telephony.
The next step involves selecting the control system and therefore the components to be integrated. The control unit, the various sensors to manage the systems, the controls for the lights and for the motorization systems, the devices for the various commands, the control elements for household appliances and various services such as video surveillance are chosen.
This is followed by the study of the system diagrams with the drafting of signals, commands and connections. During this delicate moment, the components of the systems required are transcribed on a graphic and computerized level, for example using CAD; in this way you have precise and schematic drawings of the electrical and acoustic systems, of the lighting devices, of the motors for doors and windows, etc., and all the home automation devices such as inputs, outputs, power supplies, couplers, etc., which they will then be used during the manual installation phase of the systems themselves. At this stage, spaces are identified to install the various systems; this representation is identified by IS4 (general panel), IS5 (junction box in the room) and IS6 (socket-outlets, inside which the control devices of the light points will be installed). The commands must be clear and identified in a precise way, using alphanumeric codes; for example for buttons Pl.0, Pl.1, Pl.2, ..., for sensors Sn.0, Sn.1, Sn.2, etc.
5) Examples of realization
The field of application of home automation is very wide, and adapts to the different needs of users, starting from a single house in a condominium, to an independent villa. As already mentioned, basic home automation provides anti-intrusion and environmental security and environmental comfort.
For example, in the design of a home automation system for a ground floor apartment of about 100 square meters, some specifics must be considered. As regards the anti-intrusion security, a double protection of the perimeter can be installed on the shutters and on the railings, which through sensors allow to activate the alarm. For environmental safety, gas and water sensors are placed. Finally, for environmental comfort, the switching on and off of the air conditioners is activated automatically.
Other systems are also considered, such as the management of the shutters, which can be lowered or raised according to needs, even in predefined intervals to avoid power loads; the management of the external and internal lights allows all the lights to be connected and controlled by traditional buttons or by more complex systems.
The best time to install a system of this type is during the design phase of the apartment itself, or during a renovation. A home automation system makes the home environment intelligent and guarantees excellent control.
Denise Barbaroux
USEFUL LINKS
http://it.wikipedia.org/wiki/Domotica
http://www.domotica.it/
http://www.ceiweb.it
The CEI is the body recognized by the Italian State and the European Union in charge of
technical standardization in the electrotechnical, electronic and telecommunications sectors.
The CEI technical standards help to define what the laws refer to as the "rule of the art".
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