Text INTELLIGENT HOMES
Smart homes and home automation
Back in 1923, brilliant Swiss-born architect Le Corbusier (18871965) described a house as "a machine for living in"and slowly, during the 20th century, that metaphor turned into reality. First, the arrival of convenient, electric power started to strip away the drudgery from all kinds of domestic chores, including washing clothes and dishes and vacuuming the floor. Then, when transistors made electronics more affordable in the mid-20th century, appliances started to control themselves in a very limited way, using built-in sensors and programmers. But it's only now, in the 21st century, that the vision of the fully automated home is actually being realized. Thanks to the Internet, it's easy to set up virtually any electric appliance in your home so you can control it from a Web browser anywhere in the world.
The main thing is to introduce a centralized control. In the most advanced form of smart home, there's a computer that does what you normally do yourself: it constantly monitors the state of the home and switches appliances on and off accordingly. So, for example, it monitors light levels coming through the windows and automatically raises and lowers blinds or switches the lights on at dusk. Or it detects movements across the floor and responds appropriately: if it knows you're home, it switches light and music on in different rooms as you walk between them; if it knows you're out, it sounds an intruder alarm.
How do smart homes work?
Assuming you're not (yet) in the Bill Gates league of having a multimillion dollar smart home built from the ground up, you'll probably be more interested in adding a bit of automation to your existing appliances with as little fuss as possible. Modestly smart homes like this range in complexity from basic systems that use a few plug-in modules and household electricity wiring to sophisticated wireless systems you can program over the Internet. Developed in 1975, the oldest and best-known smart home automation system is called X-10 (sometimes written "X10") and uses your ordinary household electricity wiring to switch up to 256 appliances on and off with no need for any extra cables to be fitted.
How does it work? The central controller sends regular switching signals through the ordinary household wiring, effectively treating it as a kind of computer network. Because these signals work at roughly twice the switching frequency of ordinary AC power (which works at 5060Hz), they don't interfere with it in any way. Each signal contains a code identifying the unit it relates to (a table lamp in your living room, perhaps, or a radio in your bedroom) and an instruction such as turn on, turn off, or (for lamps) brighten, or dim. Although all the control units listen out for and receive all the signals, a particular signal affects only the appliance (or appliances) with the correct code. Apart from appliances that receive signals, you can also plug in sensors such as motion detectors, thermostats, and so on, so the system will respond automatically to changes in daylight, temperature, intruders, or whatever else you consider important. With most systems, you can also switch appliances on and off with a handheld remote control (similar to a TV remote). The remotes either send signals directly to each module using radio wave (RF) signals or communicate with the central controller, which relays the signals accordingly.
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X-10 has become an international standard for controlling appliances, but it's not the only system that works this way.
Wireless Internet system
Security is one of the biggest reasons why many people are interested in smart homes. If you're away at work or on holiday, making your home seem lived in is a good way to deter intruders. A basic X-10 system can turn the lights and the TV on and off at unpredictable times, but if you really want to push the boat out on security, a wireless, Net-connected system is much better. Effectively, it's a computer-controlled X-10 system with an interface you can access over the Web. With a system like this, you can hook up webcams to watch your home (or your pets), switch appliances on and off in real time or even reprogram the whole system. Harmony Home Automation is an example of a system that works like this.
DIY (Do It Yourself) smart homes!
Lots of people like simple, off-the-shelf, plug-and-play systems like X-10: buy it, take it home, plug it in, and off you go. But plenty more of us are hobbyists, hackers, and geeks for whom the very challenge of doing something is at least as importantsometimes more sothan the thing we're actually trying to do. If you're one of these people, you're route to a smart home is more likely to be through the hacker, maker, DIY community, maybe using something like an Arduino microcontroller to link your computer to appliances around your home.
