Home Automation
Ever since the first commodity personal computers came out over 25 years ago, hobbyists and visionaries have dreamed and schemed over the automation of the home.
| In fact, not all dreamers of such automation have been computer people. Some of the science fiction that many of us have read incessantly features some level of automation, from automatic food ordering (and preparation) through to self-aware master computers who do everything from managing the accounts to entertaining and acting as a secretary/butler; not to mention actually running the heating, lights, sybaritic bathing facilities, fish tank and communications. |
It has taken a long time and the job is certainly not yet done, but we are now at the point where a reasonable job can be done for a reasonable price, and things are getting better fast. On the other hand, we now also have to contend with quite a few blind alleys from people bent on marketing something, even if it doesn't really make sense.
This article and the ones that follow will take a pragmatic look at home automation; not only the aspect of automated home process control, but also the aspects of integrated communications, entertainment and security. We will explore some of what has gone before, see what is possible, what is practical, and what is coming in the future.
The Pieces of the Puzzle
I'm going to deal first with the physical control items, since they are the things that have taken much of the time to evolve. All of the physical control systems have some sort of computer interface, and with the state of software today, they all can be controlled to the limit of their abilities from almost any computer (and to the limit of today's software, but again, that is another story).
The prize for the first item hobbyists automated is said to be a toss-up between the furnace and the lights, but in my experience, the lights won out. I helped a friend put low-voltage controlled lights in his house in 1972. He still has the house, and the automated control has gone through several generations of computers.
| The actuators were simple electro-mechanical switches. Each was about 2.5" long and sized to fit into a 1/2" hole, the standard size found in most fuse boxes and receptacle housings for standard house wire.
The control circuits were 18 gauge stranded wire running from an 18 volt DC power source. The reason for low voltage control being available was so that several different control points might control the same circuit, or several circuits might be controlled by the same push-button or rotary actuator. Later systems used computer automation as well as the physical switches. The setup to allow any controller to control any relay was done using old "50" blocks scrounged from our work with the local phone company. These were "quick-connect" blocks designed to allow cross-connection of telephone circuits in business buildings and PBX installations. Diodes allowed for a primitive "truth-table" style multiplexing. I'll see if I can get a photo or two - the ones I took in '72 are probably at the bottom of a box in the garage. |
The best known of the light/power control systems over the past few years has been the "X-10" system (see history) which has had several companies create compatible modules and controllers which use the power wires in a home as the means of sending and receiving commands. This system has grown from a small number of modules with strictly manual controls, to a fairly complete system with wireless, manual and computer interfaced control systems.
It has motion detectors, alarm fobs, sirens, wired in as well as add-on/plug-in controllers and even has high-power modules for 220 volt (I use one for the jet pump on my hot-tub.)
I've used these modules for over 14 years now (through 2 houses, moving them from the old one to the new), and within their limitations they have proven extremely useful. The main problem I've had is with the address switches (the round dials on the face of many of the units) which seem to require exercising from time to time due to what I assume is oxidation of the contacts. I understand that there is a newer (than the modules I have) series of "professional" units which either don't have this problem, or at least need more time to show it.
I have to say that I have not needed to purchase any new X-10 power units for several years (I've picked up a couple of wireless control units to add and replace a unit that got dropped in the hot tub), so will have to do my homework to really be able to represent this product as it currently is. I note that the www.x10.com site is very high pressure, with pop-unders and such. I can't say I'm impressed, but then at least the technology has not died.
The system in our current house is based upon Radio transponders mostly. It uses the PS561 "Voice Dialer" security console as the central receiver. While the alarm functions are not specifically used in our home (there is another system for that), the system is set to ding each time one of the doors is opened, or one of the motion detectors set on "immediate" mode is tripped. We use the wireless motion detectors when we leave a door open in the summer - so anyone coming close to the door trips the ding.
The serial console (top picture) is plugged into one of the serial ports on our Linux-based NFS file server in the furnace room (helps to heat the house) and is programmed via a simple scripting language and some "cron" functions to turn various systems on and off throughout the year.
Along with this, we use various flavours of hand-held remotes with up to 24 functions on each to allow us to turn on and off lights (and the pumps and heater on the hot-tub). While all are battery operated, I estimate that our total battery outlay per year is less than $100.00, including the 9-volt ones for the door monitoring units and the wireless motion detectors.
We're in the midst of deciding what we're going to do with the current house once the kids move out (something they alternate between wanting and not wanting to do on a daily basis it seems). I don't expect to take the current system with us to the next house as many of the modules have already traveled from our previous one. This series of articles will be based upon my research into the current state of the art.
The next article will deal with more recent control technologies; not that X-10 has in any way died, just that there are now competitors.
Some Resources
An interesting article on potential for viruses in home automation products I found recently. There is also an interesting thread of comments following the article.
What's Related