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energymonitor [2016/04/08 09:25] (current)
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 +====== House Energy Monitor ======
 +
 +===== Hardware =====
 +
 +
 +This topic details a mini project using the [[http://​www.eonenergy.com/​At-Home/​Products/​Products-Electricity-And-Gas/​Electricity-and-Gas/​Energy-Saver.htm|EON Energy Monitor]]:
 +
 +{{05072008.jpg?​350}}
 +
 +EON have being given them away "​free"​ when you sign up to getting energy from them. It is infact a re-branded [[http://​www.currentcost.co.uk| Current Cost]] Energy Monitor. ​
 +
 +I noticed that on the bottom was an RJ45 connector, after a bit of Googling, I found [[http://​www.yellowpark.net/​cdalby/​index.php/​2008/​06/​15/​setting-up-my-current-cost-meter| this]] and [[http://​flickr.com/​photos/​pixelfrenzy/​2499443217/​|this]]. ​
 +
 +So using Chris Hand's infomation, the interface on the RJ45 is:
 +
 +   * orange/​white
 +   * orange
 +   * green/white (pin 7, data in to CurrentCost)
 +   * blue (pin 4, ground)
 +   * blue/white
 +   * green
 +   * brown/white
 +   * brown (pin 8, data out from CurrentCost) ​
 +
 +The level is 3.3v TTL so cannot be connected directly to an RS232 port, however I don't have one of them free anyway, so I used a USB to TTL 3.3v [[http://​www.ftdichip.com/​Products/​EvaluationKits/​TTL-232R-3V3.htm|serial converter]] (also used by Chris Hand) from RS (part number 429-307). Current Cost do sell the cable for a good price, but what is the fun in that!!!
 +
 +Using an old Ethernet cable for an RJ45, connecting the USB to serial convert to the RJ45 connector was easy:
 +
 +{{05072008_003_.jpg?​350}}
 +
 +
 +Just connect the pin 4 (blue) of the RJ45 to pin 1 (black) on the TTL-232R-3V3 and connect pin 8 (brown) of the RJ45 to pin 5 (yellow) on the TTL-232R-3V3. If I get time I will make a better cable, but for now this works. ​
 +
 +
 +===== Software =====
 +
 +When the hardware connected, I used Minicom to check that it was working. There are two version of currrentCost available, one that runs at 2400 baud, and one that runs at 9600. Mine was a 9600. 
 +
 +The device spits out XML data every 6 seconds. You do not need to request data.
 +
 +I wrote a simple c program to read the XML stream and convert into a CSV file that gnuplot can understand. ​
 +
 +The code can be found {{energymonitor.tar.gz|here}}
 +
 +This application runs on my Linux server and reads and converts the XML stream into the CSV file, I also have a cgi script to convert the CSV file into a picture. ​
 +
 +   * {{powergraph.cgi.txt| Plotter Script }}
 +
 +This is an example plot:
 +
 +{{powergraph.cgi.png?​350}}
 +
 +
 +[[LatestReadings]]
 +
  
energymonitor.txt ยท Last modified: 2016/04/08 09:25 (external edit)