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
lower price of devices;
technology known to all electricians- no explanations needed.

Domotics
increased flexibility: the system is defined by the configuration, not by the cabling;
one device can have several functions;
simplified wiring system: all connections, except between the actuator and the power are at low voltage, which decreases the possibility of a fire and simplifies the structure of the fire alarm system;
low costs of changes to the system;
the possibility of remote control.

DISADVANTAGES

Traditional system
poor flexibility;
need for many devices, which adds to costs;
higher cost of materials, labour and cabling;
increased need for fire alarm systems;
the risk of users getting into contact with power lines;
costs vary unpredictably during construction;
none or very difficult possibility of remote control.

Domotics
costs of devices slightly higher;
the technology still relatively unknown to many contractors, the need to illustrate the advantages to the clients.

This is the second in the series o 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 technologijes.  

 Cubo Control is an engineering and programming studio that loves technology, automatics, Italian design, but also programming of computers and other devices: from window shades to mobile phones, from basement temperature to ship engines. It is founded with the idea to provide a unified offer of high-quality solutions at affordable prices in the field of contemporary automatics, especially domotics and industrial automatization, through careful selection of high-class equipment and affirmation of state-of-the-art concepts of comfort and energy efficiency.