Low-Speed Requirements and Automation
The biggest player in low-bandwidth home automation is the X-10 protocol. X-10 works by interjecting a 120-KHz pulse between the zero points in the AC sine wave (see "Building a Power Bridge to X-10"). To compensate for dirty power lines and other interference, commands are sent twice. Every X-10 device comes with two settable 4-bit addresses. The first address is a house code, which is designed to facilitate grouping devices together. The second number is an identity code. You can say all devices in the living areas are on Code A; devices outside, on Code B; and so forth. This makes administering the devices easier.
Controllers, which connect to your computer through the serial or USB ports, are used to govern a particular house code, or you can use a computer to control and script an entire house. Controllers are manufactured by a variety of companies and come in a range of forms (SMARTHOME shows some of the options).
You can have as many as 256 individually controllable X-10 devices. Multiple devices can have the same code and behave similarly. Some X-10-attached devices also can send commands, so, for example, the thermostat can tell a controlling computer the current temperature, and the computer can use that information along with a script to determine what action to take.
X-10 has been around since the late 1970s. IBM dabbled in this area when its Home Director was a companion system for its Aptiva computer. X-10 is a great protocol for low-bandwidth and simple devices. A common use of X-10 is for controlling lighting. One of our technology editors has a script called "goodnight" that turns up the lights in the den and bedroom at a set time and then turns them off after 3 minutes. Another editor has the lights in his television/media room ramp up over the course of a few seconds instead of coming on all at once after a movie is played. This operation is directed from a single remote control that handles the lights, TV and DVD player. The big draw of X-10 equipment is that it's easy to set up, configure and use. Compared with the complexity of many home-theater systems, X-10 is simple.
Safe at Home
A utilitarian use of smart-home equipment is for home-security systems. For instance, wired or wireless video cameras can be mounted outside the home for surveillance. You also can wire in motion sensors, glass-breakage detectors, trip wires and pressure sensors. An alarm condition, such as a window breaking, can trigger a script that turns on all the lights and activates the cameras.
Water detectors can tell if the basement is flooded. Other detectors sense heat, smoke, carbon monoxide or other dangerous situations and set off alarms, flash lights (for those with limited hearing) and/or send an e-mail to you at work. Controllers installed on blinds and curtains can close them automatically at a certain time or when nightfall is detected via a photoelectric cell.
High-Speed Applications
Of course, the really cool stuff and possibly the driving force for future smart-home technology is in the entertainment and structured-wiring spaces. We already have the technology to rebroadcast a video signal via RF from one location to another in a house. The rebroadcast isn't DVD-quality, however, and interference can cause dropouts and static. But in a house with a high-speed network, residents can pump video and audio over that network with a minimal impact on other applications.
Inside the house, with a relatively small amount of traffic, nodes and hops, QoS (Quality of Service) issues aren't a big deal. However, QoS is relevant with Internet integration, though not necessarily controllable by the end user. Video-dropout frames are highly noticeable, especially if the video is displayed on a large TV screen. Likewise, multiplayer video games are sensitive to network conditions.
In Europe, ITT Industries' Cannon division is working on high-speed structured wiring with its DiLAN (Domestic Integrated LAN) product. A partnership between ITT and Home Director will bring the next version of smart homes to the United States. In this environment, Cat 5E cabling is run through the house. Every device homeruns to the basement, where it is connected to a central switching unit. A traditional appliance -- say a TV -- plugs into an adapter (coax to RJ-45), letting it take advantage of the network. Video from a DVD player can be routed to any room in the house. Digital music files from any PC on the network can be sent to the stereo system.
By tapping into the video system, more options are available. External cameras can be tied to your television screen. When the doorbell rings, your TV screen can display the camera's signal, letting you know if the visitor is the pizza guy or your daughter's date. Caller ID information can be displayed on a TV screen, too, so that during the big game you don't miss any of the action when deciding whether to ignore a call.
Of course, it's not only fun and games: Video run over Cat 5E cable makes an office environment more dynamic. Drop several runs into an office, and you can have a building wired for cable TV without spending money on coax. A meeting room can be turned into a television studio or screening room. A rough cut video of the latest ad campaign can be played from an editing station located three floors below on a monitor in the executive boardroom, without the need to transfer to videotape or export and download files.
Beyond 2010
What's on the horizon for smart homes? With vendors forming relationships with contractors, an increasing number of homes will be prepared for higher bandwidth applications. The killer app will probably be entertainment, with automation of lighting and safety devices a side attraction. A do-it-yourself security system may attract a lot of attention, especially among those handy types who want to save money. Eventually, appliances may become automated as well. Your refrigerator may tell your PC that its door has been left open. It could also report to a repairman the integrity of certain parts and possible causes of trouble. An oil burner could send a message to the oil supplier when the tank is running low.
At first blush it may seem ridiculous that the washing machine is networked to the TV, but some of us might want the TV to signal when the wash is done. And way down the line, we may have what Home Director calls "sentient homes," like Bill Gates' famous abode, where the environment caters to the individual preferences of its inhabitants.
Michael J. DeMaria is an associate technology editor based at Network Computing's Syracuse University's Real-World Labs®. Send your comments on this article to him at mdemaria@nwc.com.
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