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Mike Quin

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Electric Dreams [Aug. 8th, 2008|06:12 pm]
Mike Quin
Having read about this setup and Kyle's implementation of the same while back I've quite fancied having a go at monitoring and graphing the power usage in the flat.

The electricity meter that is installed here is an electromechanical type which doesn't lend itself to that optical method of monitoring, so I looked elsewhere.

My initial attempt was to pick up an Efergy meter, from which I was hoping it would be possible to tap a impulse signal from, however before I had time to figure out how go about interfacing it to a PC there was a discussion on one of the mailing lists I follow about a similar device - the Current Cost meter, which handily has a serial interface (not quite RS232, but a low-voltage version of the same), and has been the subject of a few hackers attention.

As the meter is relatively inexpensive I ordered one up, along with a suitable USB interface cable and quickly had it chattering away exchanging XML with one of our computers.

Some quick and dirty Perl sufficed as an interface to rrdtool to allow me to store historical data and produce simple graphs: