X10: Home Automation
By dcb on Jan 09, 2005
When we moved into our new home five years ago, I had grand visions of an automated home. I decided on X10, which is pretty much the standard for home control. X10 works by sending signals over the power lines in your house. Lights, fans, motion detectors and other devices plug into small modules that listen for and/or send X10 commands. Wall switches and dimmers can also be replaced by X10 versions, that allow for manual control or X10 signal control.
I bought ADI's (Applied Digital Inc) "Ocelot" X10 programmable controller, which sends control signals into the power line via a bi-directional TW523 powerline module. Here is the Ocelot manual: http://appdig.com/manual/Ocelot-2.pdf
Using a GUI PC app, I designed the if/then ladder logic program and uploaded it into the Ocelot - to instruct it to manage about a dozen lights around our house... setting on/off and custom "dim" values based on daily dusk/dawn times. The controller accepted the latitude/longitude coordinates of our home so that it can automatically adjust timing based on variable sunrise/sunset times throughout the year! For example, about 30 minutes before dusk (the actual time varies from about 5pm to 8pm depending on the season: http://www.worldtime.com/dst/usa/orla.txt) the lights mounted in our china cabinet illuminate at 50% brightness, then down to 20% at 10pm, and off at midnight. I don't have to worry about seasonal drift.
Here's another advantage of X10. I installed a 500W halogen security
lamp on the 2nd floor roof line, pointed toward the backyard. It's tied
into a 110V circuit in the attic. But I needed the on/off switch
installed next to the patio's sliding glass door. Thankfully, I didn't
need to string a wire thru the walls... The switch simply sends an X10
signal throughout the house, to which the security lamp responds!
Most houses are designed with two different 110 "phases", from which 220V is derived for large appliances. X10 can have problems if the control signal is generated on the "A" phase, and the target device is on the "B" side. However, it is very easy to install a bridge amplifier in the circuit breaker panel. Here is a photo of my X10 bridge and a "whole house" surge protector. I live in the lightening capital of North America (Orlando) and have not had any surge related problems (yet).
It amazes me that I haven't touched the X10 controller in about four years! It just works! Lights go on and off or change brightness like clock work. About 50 months of continuous uptime and service!
I still intend on integrating my Ocelot into my RCS X10 Thermostats. I can include logic (if I want to) that leverages sensor data such as humidity and external temp and time of day to set the A/C set points. I also plan to tie it into my alarm system, so that when we leave the house (and set the alarm) the thermostats will adjust to save energy. Upon return (when we disengage the alarm), the thermostats respond accordingly. Also, if the sliding glass door alarm zone remains open for more than a few minutes, the A/C will be turned off (we have kids). http://www.smarthomeusa.com/ShopByManufacturer/RCS/Item/TX15R-B/
I also have a SpeakEasy module, which I hope to one day program to provide audio feedback based on certain events (eg: garage door left open past dusk, motion detector senses someone approaching the front door, the sliding glass door left open with the A/C on, etc). http://www.homeautomationnet.com/shopping/shopexd.asp?id=241. To be honest, I'm not happy with the audio quality of the SpeakEasy. I expect I'll come up with a better solution that uses CD-quality MP3 clips.
Here is someone who has more throughly documented his home automation using the Ocelot. Someday, when I finish my automation project, I'll write up something like this. http://toddjreed.home.comcast.net/ToddsHAproject.pdf