Among urban legends, one of the most persistent is that "real soon now" we'll have computer-controlled houses with refrigerators that tell us what we forgot to buy, coffee makers that spring to life unbidden and lights that turn themselves on when we enter a room. Technology demonstrations like Disney's "House of the Future" (1957) and several more recent projects have tried to show what kind of environment would result from the fully realized marriage of a computer and a house.

I've always been an early adopter — someone who likes to experiment with gadgets before they're ready for life outside the laboratory. Inevitably, this means I have a closet full of clunky gadgets, early prototypes of things we take for granted now.

About thirty years ago I heard about a high-tech replacement for a wall switch — a gadget that would turn your lights on and off by remote control. The technology was called "X-10", a scheme for controlling power switches remotely by way of radio signals that traveled through house wiring. At that time one would press a button on a remote control box that was plugged into the wall, a radio signal would travel to a particular switch, and — voila — a light would turn on.

I already had a "personal computer" in my house, and it occurred to me that I could get the computer to talk to the house. After some hacking I worked out a way for the computer to issue instructions to the X-10 remote control, which in turn would activate various gadgets at arbitrary times. This was a far cry from an interactive environment — the computer talked but didn't listen — but I enjoyed the experiment anyway.

Briefly, the X-10 technology relied on a relatively simple system — a control box was plugged into the house wiring, 120KHz signals moved across the house wiring, and plugs and switches (see second image this page) reliably responded to the signals. At least, that was the theory.

The problems with the X-10 system quickly became apparent:

• It was meant for incandescent lights, no fluorescents or appliances that included transformers (a special control with a noisy relay could be gotten for the latter).
• A typical US house electrical system has two independent branches, and it was discovered that the 120 KHz signal didn't propagate between the branches very efficiently.
• There were only 16 "house codes" and 16 "unit codes" in the system, which meant two adjacent houses with the same house code might interfere with each other, and 16 unit codes wasn't really enough for your typical hard-core nerd.
• Any sources of electrical noise tended to interfere with the control signals. One of the biggest offenders was light dimmers. Ironically, most of the X-10 controls were themselves light dimmers. Consequently, you could turn a light on, but because of the resulting electrical noise, you might not be able to turn it off again.

I have installed X-10 systems in my three most recent houses, so I've become reasonably skilled at anticipating and dealing with the various problems that came up. But I have also made changes that exacerbated the problems with X-10, like replacing most of my incandescent bulbs with the new compact fluorescent (CF) lights. The CF lights are way more efficient than incandescents and I highly recommend them to anyone, but they play havoc with the X-10 system for two reasons — they create a lot more electrical interference than incandescent bulbs, and they don't behave well with the typical dimming X-10 control meant to be used only with an incandescent load.

A brief digression. Even though X-10 dimmers can't dim fluorescent lights, the latter can in fact be dimmed. How do I know this? Because the NASA Space Shuttle has dimmable fluorescent lights on board. And how do I know that? Because I designed them.

As a result of these changes, my X-10 system was becoming increasingly unworkable and frustrating, and it sometimes would simply refuse to work, especially if I activated a particular long ceiling-mounted light bar that I recently upgraded with compact fluorescents. I began to consider replacing the entire X-10 system.

I hoped by now there might be wall switches that contain 802.11 Wi-fi nodes, each with its own IP address and the ability to report on its present state. That would be perfect — I would simply create a desktop application to orchestrate the behavior of a bunch of simple wireless nodes. And I think eventually that's the direction house control will go, because it's very easy to integrate into an existing wireless network, and there are plenty of those. But even though I believe this will be the eventual direction for house control technology, it's not feasible now (as I write in 2008).

So I recently looked at the current offerings of X-10 equipment vendors, and discovered that X-10 is being phased out in favor of something called "Insteon." Even though I hate the cutesy name, the technology is far superior to X-10 — I recently installed an Insteon system and all the X-10 problems were solved in a flash.

Insteon has some superficial similarities to X-10, and an Insteon installation can use some parts of a pre-existing X-10 system, but the Insteon system design successfully addresses the X-10 problems listed above. If I were asked to name one key property of Insteon that sets it apart, it would be the fact that each Insteon control acts as a repeater, amplifying and passing on control signals possibly meant for a control farther away from the signal source.

When I first read this, I thought it was marketing hype, and of course there's plenty of that. But I quickly discovered some counterintuitive things about Insteon networks. Typically, the larger and more complex you make an X-10 system, the worse it gets, because each new installed node sucks up more of the 120KHz power line signal, leaving less signal for controls more distant from the source. But because Insteon controls are all signal repeaters, adding more controls actually improves the performance of the system.

I was astonished. I had read this claim in the Insteon literature, but I was skeptical to say the least. At first I had only a few Insteon controls in a house dominated by X-10 controls, and the Insteon controller kept reporting that it was losing contact with particular controls. But as the days passed, as I removed more X-10 controls and replaced them with Insteon controls, the system's behavior gradually improved. Finally I could turn on all the lights in my three-floor house at once (all noisy compact fluorescents) and the system controller could still read and write to each node.

The Insteon system can do things that weren't possible with X-10, like associating groups of controls — in a room with three lights, it would be nice if all the lights came on when you switched any one of them on. With Insteon controls, that's easy to set up. And programming a sequence of timed events is easier with some of the available Insteon controllers, so you can make your house look occupied when it isn't. I'll be discussing this topic in greater depth later on.

There are some downsides to all this. At the time of writing (February 2008) the Insteon product line doesn't yet have some things I regard as essential, like motion sensors and sophisticated remote controls with lots of buttons. But there is a workaround I'll be discussing later on — you can use your existing X-10 remote controls and motion sensors, plus a master controller that knows how to translate X-10 signals into Insteon signals.

Also, the Insteon equipment is rather expensive — quite a bit more expensive than an X-10 system, but in my view this is compensated for by the fact that it actually works. So far I've spent about US$1500 on the new Insteon system, including the controller that runs the show (my system is rather elaborate, one doesn't have to spend this much to have a useful Insteon system).

I'm glad I ripped out the X-10 system and replaced it with Insteon gear. Until I took this step I was forced to realize that one of my recent choices — replacing all my incandescents with compact fluorescents — was playing havoc with another of my choices (X10 house controls). The Insteon system removes that conflict.

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