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Home Automation |
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The first step to home automation is to determine exactly what you want from it. If I pop up and exclaim "home automation!" what do you see in your head? Most of us probably visualize the ultimate pedal-to-the-metal implementation - being able to call out to some invisible listener "turn on the stereo" and voila, the stereo begins piping music from equally invisible speakers.
At the other end of the spectrum, most homes are automated "right out of the box", so to speak. For example, somewhere in the house is a thermostat that keeps the house near the temperature you select, with the same being said for water temperature. While this doesn't fit many people's definition of home automation, the point here is that it's a big scale with your goal likely being somewhere in between.
"I just want to control everything from one spot", you say. This is a reasonable midpoint, but exactly what do you mean by "everything"? List your expectations and prioritize them; it's highly unlikely that you're going to start on Saturday morning and have your house automated to your satisfaction by the time you head back to work on Monday morning. You should also consider other residents in the household; many spouses or significant others won't be as thrilled as you to have to sit down in front of the computer to bump the AC on or off.
Controlling everything from one spot can be good and it can be bad. In addition to thinking about how cool things will be when everything goes right, also give some thought to what will happen when things go wrong. For example, if almost every function in and around your house is controlled by one computer, what will the house look like if you return from a 1 week vacation and the computer crashed the first day? Sprinklers all on with water running down the driveway, inside temperature at 118° F, all the lights on, alarm bells, fans all at full speed, and a mixture of Van Halen and Andy Rooney heard from the lake in the street?
Instead of one single control, you might want to consider something with more of a hierarchy; a master control which coordinates several smaller or subordinate controls. Redundant backup controllers can keep things in line if primary controls fail, and backups which work on different theories are better yet. For example, let's say that you have a controller which has a temperature sensor in it to control the heater/air conditioner. A good backup could watch the amount of time that the heater/ac has been on instead of measuring the temperature; if the heater's been on for more than 10 minutes, maybe something's wrong - the primary's relay got stuck, its batteries died, or its temperature sensor has failed in some way. So the backup shuts down the heater or switches to a third controller.
The hardest (or most complex) part of home automation is the hardware that reports back to the controller: imagine that you are in charge of a flame thrower and your job is to use it to keep a room's temperature constant. Your challenge is that you aren't inside the room, so you have no idea what the temperature is - all you can do is yank on the lever to turn the flame on and let it go to turn the flame off.
Interestingly, many sites with automation as a topic don't mention much, if anything, about feedback. Automation is defined as 'the automatic operation or control of equipment, a process, or a system'. Automatic is defined as 'acting or operating in a manner essentially independent of external influence'. So being able to turn something on or off remotely isn't really automation, it's just control.
Following the definition of automation, a porch light which is controlled by a timer is indeed automated. How effective is the automation, however? Depending on the time of year, the light will either be on for a couple of hours longer than it needs to be or the porch will be dark for a couple of hours each night. A dusk/dawn detector is more effective, since it will 'automatically' (aren't I clever) adjust itself year round. Intent should be considered as well - do you want the porch light to be on all night, or do you want it to respond to motion?
Home 'automation' systems abound in the marketplace. Control-only, modular solutions tend to be reasonably and even dare I say economically priced. When you look at feedback components, however, you can quickly find yourself blinking hard at your screen and you can sometimes actually feel your wallet shrinking up against your hip at the horror.
I think we can find a good balance by combining some off-the-shelf products with home-made ones. The X-10 controls are reasonably priced (their 2-way modules notwithstanding) and are practically a universal standard, with their transmission protocol being known. They have a number of very desirable and well packaged components (keychain remotes, woohoo!) and aren't an exclusive source: many other companies produce X-10 compatible products.
I believe in reinventing the wheel under any of the following conditions:
Number two is rarely true because of the cost effectiveness of mass production. Of course, many DIYers don't really care about that anyway - the point, they'll say, is to do it yourself and have fun doing it. And I admit that they're not at all wrong; a lot of satisfaction comes from knowing that you did something yourself, regardless of how many others have done it. I'm just saying that as a general rule I have a hard time justifying spending twice the money to build something that I can trot down to the hardware store and purchase then install in 2% of the time. However, I can almost always make number three a reality, so I am able to ignore number two altogether.