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Issue #233 December 2009
Home Automation: Everything and Nothing
by Steve Ciarcia
One area that’s changed considerably over the years seems to be home automation (HA). A niche interest for sure, rolling your own home control system (HCS) these days doesn’t seem to have the same intensity it once had. Of course, some of us are just diehards.
The term “home automation” is so loosely defined that it means everything and nothing. For many homeowners, it’s simply the ability to control the lights. Others say it’s having the ability to control the HVAC system. And still for others, it means distributed audio/video. Because it is such a generic term, there are a variety of vendors and products that all claim to add “home automation.”
In my opinion the definition conflict is about whether you consider the conveniences provided by individual smart controllers in new HVAC systems, wireless HDTV networks, and motion-controlled light switches as genuine control, or does it still necessitate having centrally controlled decision-making and a sophisticated HA network to define real automation? ;-)
Like many readers, my opinion has changed over the years. Twenty years ago, I felt that HA was solely achieved using a central controller and hard-wired I/O control. Want the outside lights to turn on no later than 6 PM but prefer actual dusk? Attach a light-level sensor to an HCS input and write a program routine to turn on the lights based on the analog light-level input or the real-time clock value, whichever reaches its set point first. Tired of simple mercury tilt switch HVAC thermostats that leave you too cold or too hot? Hard-wire a couple temperature sensors to the HCS and put a few pairs of relay contacts on the HVAC? A few lines of HCS programming code and you have a rudimentary PID-controlled environment. It takes a lot of expertise and money, but string enough wire and write enough code and you could control the world.
Today I’m still excited about HA, but I’m a whole lot more conservative about whether I have to wire and control it myself to call something “automated.” For example, I just had a new 5-ton HVAC heat pump installed at the cottage yesterday. I had all kinds of sensors and contacts attached to the previous unit so the HCS could automatically adjust its temperature set point to maintain a constant humidity level when the house was unoccupied. The controller on the new 15 SEER unit has an “away-from-home constant humidity” setting that now does this automatically. I still have the HCS monitoring inlet and outlet temperatures (to ascertain efficiency and proper operation), the condensation float-level switch (so the water isn’t pouring all over the garage floor), and the power line (to know if the HVAC is just waiting or totally dead)—but I’m not physically controlling it anymore. Traditionally, HA has always meant adding customized supervisory control and monitoring to make things work the way I wanted. Today, many of these functions are simple selections on a commercial product’s high-tech integral controller and it doesn’t need customized intervention. In short, I no longer have to personally control the device. I just have to know that someone or something IS in control. ;-)
Like the age-old argument about computer architecture, distributed versus central control is perhaps the defining catalyst for people to go through the expense of traditional “home control” installation. Yes, there will always be the young engineer trying to impress his girlfriend with drapes that automatically close, lights that automatically dim, and a stereo that turns on a specific romantic song as he enters the house and says, “Sara, I’m home.” That’s fun and ego boosting (I did it myself at one time too), but the present and evolving sophistication of commercial appliances, lighting setups, HVAC systems, and entertainment systems has created an un-networked, but nonetheless effective, de facto, distributed control environment. Years ago, we could telephone our HCS and have it simulate the IR remote control to the VCR and set a program to record. Today, a couple clicks on an iPhone connects you directly to your DIRECTV receiver and the program settings. Who needs the aggravation of a man-month of HCS program development and debugging?
The extent of the sensors, cameras, I/O controllers and peripherals in my home control installation is elaborate overkill by any standard. (Let’s chalk it up to legacy upgrades.) At one time, all its programming was designed to customize the lighting, environment, and entertainment in the house. Today, the majority of those customizations are standard control features in the individual devices and the “home control system” has evolved into a “home supervisory monitoring system”—with, oh, by the way, a bunch of “optional” control. I no longer have the fun of saying I’m running the entire show, but at least an HCS hardware failure or software glitch doesn’t take the whole house down with it. ;-)
So, finally, I can address the question most asked by newbies: So what’s so valuable in the house that it needs all this security and control? It’s the home control system, of course. ;-)
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