network enabled power meter

Discussion in 'Electronics & Electrics' started by geniesis, Nov 15, 2009.

  1. geniesis

    geniesis Member

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    Are there any commercial electricity power meters like the "cent-a-meter" or efergy's power meter that are network enabled. Ie, can connect to the local LAN network via wifi or something.

    Essentially, I wish to get a whole bunch of these devices to monitor all the electrical devices in the house. With them wifi attached and possible with SNMP, use something like cacti to poll and log the instantaneous kW and kWh.

    I can then get a combined total which would represent the house hold usage rate.

    The reason I want to do this is that the electricity bill is about 2 times more than I think it should be.

    Even if I can't get it for all devices in the house, I would at least like to be able to attach to the incoming power line to the house. The problem I have is that the diameter of the cable is too big for me to clip the power meter onto and it appears that the cable in the meter box already has the neutral and active combined.

    Any suggestions for that?
     
  2. octagonalman

    octagonalman Member

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    Sounds like an expensive project. Are you sure that you are actually consuming the 'extra' electricity and that it isn't just an estimated meter reading that's responsible for the large bill?
     
  3. bogaurd

    bogaurd Member

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    You can modify devices like the kill-a-watt to make a tweet-a-watt without too much hassle :)
     
  4. CaveDog

    CaveDog Member

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    So, I'm lazy and copy-pasted this from my own forum, but meh. Have a look.

    ==============


    Project: ePowermeter

    So, thanks to Dav (thanks Dav) getting the reflective optical sensor working, I now have a fully working Power Meter. The way it works is pretty easy. The power meter outside (pictured) has a spinning metallic disk. The more power you use, the faster the disk spins. If the disk spins 187.5 times, you have used a KWh. The disk has a black mark on it. The reflective optical sensor returns a lower value when the silver section is in view, and returns a higher value when the black section in view. It can then determine how quickly the disk is spinning 's'.

    Apply this function;
    current power use per hour = (1000/187.5)/(s/1000)*(60*60)

    [​IMG]
    Yep, blu-tac. Once complete, the sensor will be mounted to the inside of the panel door.

    [​IMG]
    The unit itself. It will be PoE powered, and mounted nicely in the box. Currently its just sitting there.

    The extra section you see there is the not yet implemented CT monitoring unit. Soon, I will have this device hooked into the study circuit (yes, there is a special circuit just for the study) and be able to monitor total power, and study power.

    The system is pretty accurate (down to 5-10w), but some devices (hard drives spinning up, fridge kicking in, laptops charging) makes it a bit all over the place. Its only meant to give me a overview of the power use, not a exact measurement. After it was plugged in, I was able to determine a few interesting values.

    800w - Bathroom heater lights.
    1920w - Dryer.
    145w - Tincan-files
    72w - Tincan-files2
    210w - 42" TV
    89w - Dining lights
    231w - Kitchen lights
    60w - 2 x 24" Monitors
    100w - Fridge compressor
    272w - Oven

    As you can see, the kitchen lights will be changed soon.

    Code below. Have a squizz through and make my code better.
    Code:
    #include <Ethernet.h>
    
    byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
    byte ip[] = { 192, 168, 1, 150 };
    byte server[] = { 192, 168, 1, 22 }; // Tincan-LAMP
    
    int CTpin = 0;    // select the input pin for the potentiometer
    int CTval = 0;       // variable to store the CTvalue coming from the sensor
    int CTmin = 1024;
    int CTmax = 0;
    int i = 0;
    
    int OPTOpin = 1;
    int OPTOval = 1024;
    int OPTOtrue = 500;
    long OPTOfreq = 0;
    long OPTOlast = 0;
    long OPTOwattsph = 0;
    
    long interval = 1000;
    long previousMillis = 0;
    
    
    
    void setup() {
      Serial.begin(115200);
      Ethernet.begin(mac, ip);
      delay(3000);
      Serial.println("System Started.");
    }
    
    void loop() {  
      OPTOval = analogRead(OPTOpin);
      if (OPTOval > OPTOtrue)
      {
        if (OPTOlast + 2500 < millis())
        {
          OPTOfreq = millis() - OPTOlast;
          OPTOlast = millis();
          OPTOwattsph = (1000/187.5)/(OPTOfreq/1000)*(60*60);
          Serial.print("OPTO - (");
          Serial.print(OPTOfreq);
          Serial.print("msecs) ");
          Serial.print(OPTOwattsph);
          Serial.println("watts per hour.");
          Client client(server, 80); 
          if (client.connect()) {
            client.print("GET /ePowerMeter?optval=");
            client.print(OPTOfreq);
            client.println(" HTTP/1.0");
            client.println(); 
            Serial.println(">");
          } else {
            Serial.println("?");
          }
          client.stop();
        }
      }
      
      
      CTval = analogRead(CTpin);
      if (CTval > CTmax) 
      {
        CTmax = CTval;
      }
      if (CTval < CTmin)
      {
        CTmin = CTval; 
      }
      
      if (millis() - previousMillis > interval) 
      {
       previousMillis = millis();
        
        CTval = (abs(CTmax - CTmin - 3)) * 133;
        Serial.print("CTval- ");
        Serial.print(CTval);
        CTmin = 1024;
        CTmax = 0;
        i++;
        if (i == 10) 
        {
          i = 0;
          Client client(server, 80); 
          if (client.connect()) {
            client.print("GET /ePowerMeter?val=");
            client.print(CTval);
            client.println(" HTTP/1.0");
            client.println(); 
            Serial.println(">");
          } else {
            Serial.println("?");
          }
          client.stop();
        } else {
          Serial.println(); 
        }
      }
    }
    
     
  5. Goth

    Goth Grumpy Member

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    Is that an Arduino with an Arduino Ethernet Shield?
     
  6. Pugs

    Pugs Member

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    something about that second pic makes me very unsettled and concerned...
     
  7. Odje

    Odje Member

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    CaveDog: Care to share the schematic?
     
  8. Code_Nerd

    Code_Nerd Member

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    How does EA view a device like this?
     
  9. Odje

    Odje Member

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    Don't think EA would care as you are not affecting or tampering with the operation of the meter. As long as you don't impede meter readings by the metering guy there shouldn't be an issue.

    Plus CaveDog does not live in a EA area :p
     
  10. painkiller

    painkiller Member

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    Whats there to be crying about. Nothing is attached to the power mains at all. Just seems to be some sensors and other stuff powered by POE?
     
  11. Pugs

    Pugs Member

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    no crying here moron.. just a statment of concern
     
  12. nEBUz

    nEBUz Member

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    I'm told that this kind of tech is under development by various interests and should be available within a moderate to very short timeframe :thumbup: ;)

    I know I've been looking for something similar for a while in my line of work (automation/etc..), which lead me to ask around the industry about developments! Very interesting stuff ahead to be sure!
     
  13. Odje

    Odje Member

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    It is called a Current Transformer! They have been around forever and used in the automation industry.
     
  14. CaveDog

    CaveDog Member

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    There are a couple of Commercial kits getting around that have a CT clamp component that sits inside your fuse box, and a wireless module that sits on your coffee table. It transmits the data over, and you can see your current usage, days usage etc.

    Also, black and Decker have a commercial unit which does pretty much what I am doing... US only on that too and from what I hear, not hackable.

    Unfortunately the only ones I found were 110v systems.

    Yep. I have since modified my Ethernet module to be POE. It works a treat.

    Its super simple. Just a Optek OPB705. Hooked up the IR LED, and had the arduino monitor the feedback.

    I'm in Vic, so we dont have EA, but I have had a SP Ausnet (same thing) guy come knocking at the door. Thankfully he was a pretty switched on bloke, and understood that the device was simply blu-tacked onto it. He suggested that I mount it to the door of the fusebox, so that when you open it up, it doesn't touch any-more. I havent gotten around to that yet, but I will.
     
  15. nEBUz

    nEBUz Member

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    Yes, you could use a CT to do the current measurement, but that isn't the issue - we are quite good at measuring things (additionally, voltage and phase shift should be measured).

    The issue is that there isn't currently much in the way of comms. (ethernet/wifi/other) enabled power-measurement equipment in the consumer field. You could use industrial gear, but it costs a bomb and is ugly/big.

    This 'smart' metering gear is what a lot of people are asking us for, and what I'm told is coming (and should be cheap enough for real people too :thumbup:)


    If you want to homebrew per-room stuff, then the options are endless, but you want to feel pretty competent with some sort of micro, network code and the appropriate physical interfaces.

    Alternately you could save money and time and take CaveDog's approach and just get power for the whole house =)


    .. also by automation I mean home, commercial, museum, etc. automation, not industrial automation :lol:
     
    Last edited: Nov 18, 2009
  16. Goth

    Goth Grumpy Member

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    http://github.com/lukeweston/hack-a-watt

    Here's my open hardware power measurement project that I'm working on, not complete yet, although we're getting two nice sinusoidal waveforms into the microcontroller. More software development and hardware tweaking is desired.
     
  17. OP
    OP
    geniesis

    geniesis Member

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    The only commercial thing i found was TED 5000 (by theenergydetect.com guys).

    However its US only (hence runs on 120v). They say their making a 240v version for end of q1 2010, but i doubt it will be here for a while.

    Anything else like TED thats avail now in aust or am i going to have to wait?
     
  18. jmoihl

    jmoihl Member

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    Not quite the networked and individual power monitoring device the OP was looking for .. but I believe the solution to OP's problem to isolate the power usuage around the house can be easily done using a "wireless energy monitor". Currently offerred for $50 installed as part of the climatesmart home service to all residents in QLD and free for Brisbane residents after $50 council rebate.

    It measures the current change and transmit the data to a wireless monitor device which can display current power usage in KW, kWh /month , green house gas in KG/hour, as well as setting your tariff to see an estimate of your bill...etc...

    I have one installed at home and have to say it works really well, better than I expected. I can see the value change in watts (meter displays in KW down to 3 decimal places) when i switch something as small as a light bulb on/off .. ie value decreased by 18W exactly when i switched off an 18W energy saving lightbulb.

    you simply walk around with the wireless device and switch on/off your appliances/lights/power points to see how much energy its using. :thumbup:


    I have seen it elsewhere on ebay/ via google for around $100AUD (can't remember exactly).. but you'll need to get a sparky to fit it in your meter box which adds to the cost quite a bit.
     
    Last edited: Nov 18, 2009
  19. Imitation

    Imitation Member

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    They want one that has network connectivity..
     
  20. jmoihl

    jmoihl Member

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    yah...i was editing my post and you beat me to it...

    but that sounds like an aweful lot of work/cost involved to isolate/find power usage....so I'm just offering another option

    ultimately depends what the OP wants
     

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