This is a rather different topic to my usual posts. A few weeks ago, I invested in an electricity monitor. In case you haven’t come across them, they are little devices which monitor your electricity usage and display useful information, such as your current and historical usage. Because I am a programmer, I did a bit of research to find one that I could access the data on and ended up with a Current Cost ENVI-CC128, although I did also need to get the USB Data Cable to connect it to my PC.
I was quite impressed with how easy it is to connect the transmitter (it just hooks around a specific cable going into the electicity meter (you can get extra transmitters – it can take up to three if you’ve got a 3 phase supply or multiple meters)). The USB cable has practically no documentation though, other than a little information on Current Cost’s website and a total lack of understanding what I was asking for from their technical support people, which is a little odd, considering that they don’t actually supply any software with it themselves – you have to find it yourself or write some.
I worked out fairly quickly (with a little help from Googling other people’s experiences with the CC128) that the USB connection works as a simulated serial port which spews XML out when it receives a reading from the transmitter (usually every 6 seconds). It also spews out totals every hour, but I haven’t bothered with those yet as I have a machine running the whole time, so I am currently just logging the readings to an SQL Server database as they happen.
I’ve also written a nice little program using ComponentOne’s charting component (C1Chart) so that I can specify a date/time range and get a graph of usage, either by individual reading or grouped by minute, hour, day, month or year (eventually!). This has provided me with all sorts of interesting information, and given me a good picture of our electricity usage.