http://www.picobay.com/projects/2009/01/real-time-web-based-power-charting.html
This post details a real-time web based household power usage chart. The end result is a live chart in a web page that updates every 10 seconds with the instantaneous power usage for my entire house. The electrical current is measured on the main lines entering my home with AC clamps. The signal is then conditioned with a simple circuit and monitored by an ioBridge module. The ioBridge module takes care of feeding the data to the internet without the need for me to host a power hungry home web server. By using ioBridge widgets with a few JavaScript API calls on my web page, I am able to chart the data with Google Charts as it is measured and make kilowatt-hour calculations in real-time.
Dane linked me to this earlier today – definitely going to be giving this one a go. Just leavin’ this here for now until we get around to it… looks like a great weekend project. Especially since both of our machines running are probably more than half of our electricity bill as it is…