Building a Home Power Monitoring System
	Introduction | Planning | Installation | Software | Wisdom
		Introduction Have you ever wondered how much power that microwave takes to pop that bag of popcorn? What about your toaster or coffee maker? How much power does that 'energy efficient' refrigerator actually use? And does it really make a difference if you turn all those lights off all the time? The problem with wondering about this stuff is there isn't really much you can do to measure it. Sure you can use a meter to measure an individual device here and there, but what does your whole house look like? About a year ago I was hired to develop a web based power monitoring application for data centers. The application was designed to monitor thousands of individual branch circuits using current transducers at the breaker panels. Among other things, the data logging requirments were to provide one year of min/max/mean measurement data with one minute resolution per circuit. Since I had all the hardware for testing, I figured what better way to test things than to install it in my own home. I'm a software guy by trade, but have done my fair share of home improvement projects (How to build a ceiling dome) and other construction hacks (Building a trade show booth on a budget). I figured wiring current transducers to my breaker panel would be a quick little project that would yield all kinds of really interesting data about my house... in effect providing me with a 'sniffer' for my electrical network. A couple of warnings however... DON'T try this at home unless you know what you're doing. Aside from being electrocuted, incorrect wiring can burn your house down. If you think this is cool and try to do something similar on your own and kill/damage/burn/destroy yourself/friend/pets/computer/etc, don't blame me as you've been warned! If you live with someone, or in particular are married, and you feel like trying to do something like this, make sure you have a pretty good idea of who uses more power before you start. I busted my wife for using the toaster (at 10 amps a pop) and leaving the lights on too much until she pointed out that my server rack consumes about 5 amps continuously (plus another 4 when the cooling system is running at max capacity)... ouch! Anyways, what you see below is perhaps the ultimate in home power monitoring hacks. Update... I've received a bunch of emails about where to get the hardware to do this. The hardware I'm using is pretty expensive (I got mine for free) but the company I did the project for (TrendPoint Systems) is in the middle of building a lower cost version with better than meter grade accuracy. One of the planned versions has 14 channels (vs 42 on the hardware I'm using) and I've convinced the CEO to make some of these boards available to the hacker community (without the gui software however) for a reasonable price (I don't know what that will be at this point as it's not my product, but I'm assured it's going to be reasonable for do-it-yourself folks so long as you can program). Anyways, if you're at all interested, send me an email (david(at)kondra(dot)com) and I'll let you know more details at they emerge. NEXT >
	Introduction | Planning | Installation | Software | Wisdom

Kondra Systems