Combined Gas and Electricity Monitor
Published on 28 Feb 2009 at 10:52 am.
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I have been working with a nice electricity device called CurrentCost to see if I could combine it with my gas monitor. This is proceeding but a little slowly because of some specification issues. Anyway, just as I thought I was getting there came a total distraction: the arrival of a new electricity meter from Landis + Gyr (see pic). This is not a “smart meter” as such but it’s a pretty useful device given that it has an LED indicator with a strong and clean pulse representing 1/1000 kWh. An LDR is easily taped over this indicator and fed into a microcontroller.
Excuse the scruffy taping job. I’ll think of a nicer way to hold it in place. A key feature is the opaque tape (not visible in pic) to maximise the contrast and therefore the input voltage swing.
This is now plugged into the same Arduino that’s watching my gas consumption and the software is modified appropriately. The device keeps track of the readings and sends updates periodically to the server over the Internet. The server can then, on demand, produce a record of what’s been consumed and how much we’ve spent. Once we build up a few months’ history our patterns of consumption should be clear so we can also see the broader trends and better refine our usage.
The use of power at night is a known problem since we (foolishly) allowed electric underfloor heating to be installed in part of our extension. At the moment we’re on a single tariff for electricity and this is costing about 9p/KWh. Iwill now do some more accurate sums to see if we should be on a dual tariff.
The other thoughts I’ve had all along with this project are to benchmark our consumption against those of comparable properties and also to invest in (even) more insulation and airtighting.
To facilitate that I need to finish the design (e.g. to add external temperature and re-calibrate the internal temp which is over-reading). Then I’ll see about building more robust prototypes for others to use. Let’s see what time allows. PS. Ext. temperature added (image replaced).
