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Real-Time Power Monitoring Options?
tedpearson writes "I've wanted for quite a while to be able to look at my electricity usage in graphed form, both real-time and historical data. There seem to be a number of options for power monitoring in existence: some that hook into Google PowerMeter, others to Microsoft Hohm, and some that are standalone units. I've also seen DIY projects using Arduinos for reading the data and sending it to a computer. But I haven't found anything that is quite what I'm looking for, and I am hoping the Slashdot community can give me some advice. What I'm looking for currently: Some sort of device(s) that a) accurately measures power usage, b) allows me to access the data for storage in a database for my own graphing/analysis purposes, c) will work with MacOS (doesn't require Windows), and d) doesn't cost more than $150 or so. DIY is fine, though I don't understand circuit design, which is keeping me from designing something myself."
This is about as cheap as it gets for a DIY project. If I were to give you a quote for a commercial grade version you'd shoot me in the eye. http://www.iobridge.net/projects/category/projects/ http://www.iobridge.net/projects/2009/01/real-time-power-monitoring-system/
Stick a webcam on it, do ocr to text on the numbers. Sheesh!
At the meter, you can calculate the power draw. Look for the Kh value on the meter, and count the number of seconds it takes for the disc to make one full rotation. Then, use this formula:
W = Kh / (Seconds / 3600)
to get the power draw in watts.
Of course, this assumes you're still using an old-school spinning-disc meter.
Oh, no! You have walked into the slavering fangs of a lurking grue!
It's a little more expensive that what you want -- $200 rather than $150 -- but other than that, I think it's exactly what you're looking for. The gateway device itself stores sufficient data to allow you to look at short-term detailed usage and long-term trends via its web interface, but if you want more than that, you can set up something to periodically poll the device, downloading detailed, per-second, usage in an XML format. You can then store that data however you like, and mine it however you want.
There may be other solutions out there, and I'm interested to see what others suggest, but I have a TED unit and I couldn't be happier with it. It also uploads to Google PowerMeter.
http://www.theenergydetective.com
Note to ACs: I usually delete AC replies without reading them. If you want to talk to me, log in.
1) Wander around house, see if lights, appliances, devices are on/plugged in.
2) Make arbitrary decision about power usage.
3) Turn off/unplug device.
There. Now go play outside.
The Analog Designs ADE7763 is a pretty awesome chip for doing this sort of stuff. Here's the appnote in a pdf, and here's the chip itself. It's quite easily interfaced to an Arduino using SPI. I just laid out a board interfacing this to an ATMEGA1284 for doing power quality monitoring and logging, but it's for an internal project so I can't just hand out the code or layout, but it was a dead simple chip to work with: one crystal and two caps were all it required for support, and if it were interfaced to an Arduino, that could handle all the I/O to a computer or write to an SD card.
Nostalgia's not what it used to be.
Check with your power company, especially if you are with a smaller co-op. I write software that does the analysis and historical reporting on modern (aka, "smart", the kind that can phone home with readings on usage, peaks, etc, and all over the powerline itself) meters, and we have all that data like you're describing. More complex systems allow for complete home monitoring, but they do require some specialized devices inside the house.
Here's a link (ok, the first on google I came across on the terms you need) but still, this will get your foot in the door. HTH. http://www.sdge.com/smartmeter/homeAreaNetwork.shtml
If you're in with a bigger firm, sorry charlie, not much to suggest there.
2^3 * 31 * 647
I have an older version of the CurrentCost monitor..
When I get some extra $ together will likely upgrade.
http://www.currentcost.com/
So register one twitter account per outlet, have them all tweet power usage, then register another twitter account that retweets all the others and then tweets the total usage. Once you start generating that much twitter traffic, CNN will eventually start publishing your tweets on the front page of their website, since their primary news gathering activity these days is reading and re-posting "hot" twitter feeds. Then, you can just log on to cnn.com whenever you want to know your power usage.
Sheesh, do we have to think of everything?
See http://www.etherbee.com/products/ECM1240/default.htm
and see what you can output with one of those guys:
http://marc.merlins.org/perso/linuxha/post_2010-08-13_Fine-grained-house-wide-power-monitoring-with-Brultech-ECM1240_-ecmread_py-_with-net-metering-support_-and-graphing-with-cacti.html
There is one caveat: you need windows for the initial setup, although I did it in vmware, maybe it works in wine too, but since then it's been running fine on linux (and it would work just the same on MacOS since it's a python script).
Marc
I use TED. It's right around your price range. It monitors whole-house power usage in real time and has a USB-Serial interface which you can easily suck data out of with Python script. I personally do all the data logging on a Linux box and export it through a web interface.
Sincerely,
The Bay Area
-- Let us endeavor so to live that when we pass even the undertaker shall be sorry. -- M. Twain
Are you saying you're un-lazy enough to walk a few feet outside and read your meter? And write down the reading? Every five minutes? For a month?
Yes, it's very easy to track your average monthly power usage, it's right there on your bill. It's also easy to check your instantaneous usage by looking at the meter. What the OP wanted to know wasn't just a point measurement, but a running graph to see how it varied from hour to hour throughout the day.
Pound! Bang! Bin! Bash! is this a shell script or a Batman comic?
I had that desire too, but my electronics skills were up to an overkill DIY solution...
http://www.delorie.com/electronics/powermeter/
I record watt-seconds for each of 64 circuits once per second to a linux server.
This appears to be a re-branded product marketed by Blue Line Innovations http://bluelineinnovations.com/. I purchased one of these about three years ago for about US $200.00. It works moderately well although the meter-reading device doesn't seem too happy with New England winters.
The unit can read meters with a spinning dial and meters with a digital display. Digital meters contain an optical port through which the device monitors the meter.
The model I have can't interface with a computer; the company might have models that will do so.
Another product I purchased is produced and marketed by BrulTech Research Inc. http://www.brultech.com/. The unit is the ECM-1220 and works quite well. The supplied software is written to run under Windows, although BrulTech are very helpful in providing sample software and code for anyone who might like to port the product to another operating system.
I had marvelous plans to write some GPL'd software for OS/X and Linux; as with many projects life got in the way.
As I recall, this unit and the supplied software (not the sample code) cost me about US $300.00.
The product uses current transformers. On my 200-amp 220 VAC panel I have two current transformers - one for each leg of the load to the house.
Monitoring each load is possible with enough current transformers and host units; the cost would be (for me) prohibitive.
I strongly prefer the BrulTech unit over the Blue Line product, although each is quite usable.
Of course PG&E really wants the capablity to charge us double on the hottest days
Wait, you mean they want the capacity to raise price when demand spikes, so as to help the market forces discourage use when reduced use causes the most benefit to the market, and thus allow them to stretch out their infrastructure allotment and help save the planet?
Shocking, SHOCKING I say! :)