The Open Hardware web community has made plenty of examples about power monitoring and consumption knowledge: from ladyada’s tweet-a-watt to Jarv’s Home power Monitoring. [Greg] shares code & circuits on his own power monitoring system based on Wifi Communication.

First things first – this project is a blatant and obvious rip-off of John Jarvis’ power monitoring project! A few minor details have changed but I have to give him credit for a great project idea. I was intrigued by John’s power meter and it gave me an excuse to buy and try an Arduino – a handy and fun little embedded project platform! John’s power meter uses the ethernet shield and some CGI scripts, etc., to talk with his server – I went with AsyncLabs WiShield to put my power meter onto the network – my backend to get the data to the server is also a bit different (but of course).

The basic idea of the project is that an Arduino Duemilanove is continuously reading the analog pins that a couple TED Current Tranducers are connected to (one per phase). The Arduino does a little smoothing/averaging of the data and waits for an IP connection to send that data out on. Another machine has a Win32 service running on it and every minute it queries the power meter for its current data; the data that is received is stuffed into a MySQL data base. When a web request comes in to view the data a few pre-canned charts are generated real time and returned to the web user’s browser.

via [SlackLab]