Another approach to power meter data harvesting

[Dodgy] wrote in to talk about his power meter data harvesting programs. This uses the same hardware by CurrentCost as the hack we looked at over the weekend but [Dodgy's] implementation is different. It’s separated into two parts, the first is a webserver written in C that harvests the data and makes it available at an address on the network, the second is written in Perl to format and upload data to Google PowerMeter.

The C program serves data on a configurable port, defaulting to 3090. All of the data can be accessed in one line of code by loading http://127.0.0.1:3090, or individually with subdirectories like /watts, /time, or /tempr. From there you can do what you want with the data. The second part of [Dodgy's] suite is a Perl script that polls the C server and sends the data to your Google account.

One thing that interests us is his comment that you should be able to compile the server side C code for an embedded device. It would be a nice energy savings to be able to upload data regularly without a PC running constantly.

Smart power meter interface for the Linux crowd

[Graham Auld] got his hands on an energy monitor for free from his utility company. The device seen in the insert provides a nice LCD display but he wanted a way to graph the data over time. There was an included cable and a method of using Google PowerMeter but only for Windows computers. He did a little poking around and came up with a Perl script to interface the meter with Google’s tools.

The hardware module is known as the Current Cost CC128 and the developer was nice enough to publish an XML output description which [Graham] used in his script. From there it’s just a matter of registering and authenticating through the Google PowerMeter API. The script is not fully polished yet but it serves as a road map for your own implementation.

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