The Internet of Things promises real-time monitoring of appliances, HVAC, and just about everything else in the home. One of the biggest technologies behind this is the smart meter, an electrical meter that will tell you how much power you’re sucking down from the grid at any given moment. A meter need not be smart, though, because [jlbrian7]’s entry for the Hackaday Prize does the same thing without an entirely new meter.
[jlbrian]’s power monitor is a non-intrusive monitor for electrical systems, allowing anyone to retrofit an electrical meter – or just a single breaker panel – with smart meter tech. It uses a small current transformer to monitor the amperage running through a wire. By sending that information to the Internet, anyone with this system gets power monitoring with much higher temporal resolution than what the power company provides in a monthly bill.
As a nice little addition to his Power Monitor, [jlbrian] is adding a few environmental sensors to his data logging platform. This allows for a little bit of interpolation to figure out what all that power is actually being used for; if the power turns on and a few minutes later the temperature drops, there’s a pretty good chance the AC just went on.
19 thoughts on “Hackaday Prize Entry: Real Time Power Monitoring”
I cant tell, but it doesn’t look like it measures voltage – only current. The voltage on the grid fluctuates quite a bit depending on the load in the area, wouldn’t be too accurate.
eagerly want this!!
Get one of those. Does a LOT more and has all the data as a simple XML url so you can harvest the data yourself. I tried to build one from scratch and ended up spending more than this.
But 200 bucks !
I completely agree that to manage something, you need to monitor it. But all this micro-monitoring leads to what? If you see a single usage spike will you run around the house turning things off?
Then you move to Phase II – adding monitoring to each power socket.
(Phase III is when you realise you’ve missed the hard-wired stuff like ovens & lights.)
It would be good to add voltage measurement to get a better estimation of the power. I would use shunts and optocouplers somewhere to add isolation rather than transformers meters use either. HVAC means 200kV or at least 11kV, definitely not 120 V.
WTF? Not sure what kind of HVAC you are using….220V is pretty standard for residential in North America.
probably a misunterstanding. According to Wikipedia HVAC “(heating, ventilating, and air conditioning; also heating, ventilation, and air conditioning) is the technology of indoor and vehicular environmental comfort.” BUT “HVAC may also stand for high-voltage alternating current.”
LV = < 1kv
MV = 1kv
HV = > 66 kv
Generally speaking and the changeover voltages vary somewhat by country.
Hmm, that didn’t work now did it. What happened.
LV less than 1kv
MV less than 66kv and greater than 1kv
HV greater than 66 kv
I should have elaborated a bit more. I was complaining about the nomenclature as you pointed out. Anything below 1kV is low voltage despite being dangerous. High voltage AC means really-really-really-really-dangerous voltages meant to transfer bulk power very far.
I made a similar thing a few years ago. This is the sensor:
It is a Rogowski coil and will measure from around 0.3 amps up to about 2000 amps. The sensor has a Pic in and is run from mains because it measures phase angle as well as voltage and current. It uses 433 MHz to talk to a Raspi that has RRD running to save data.
That’s a great project. Did you write it up at all? I’d be interested in reading that.
0.3 amps is quite alot thogh? Thats 40-80 watt that you cant sense. Did yu share your design somewhere?
I could have the lower threshold lower but the upper threshold would also drop and it needed to be 2000 amps. It was designed for substation use (EU not US) so the Raspi will receive up to 24 sensors for installation in a sub station. It isn’t written up anywhere though there will be some threads about it on the Hackaday forums I think, I really struggled getting a safe shutdown on the Raspi in case of power loss so there will be a thread on that. A typical UK sub will have 6 feeders at three phases and one or two busbar incoming so 24 potential measurement points. More than that and you needed two Raspis because as we all know the Raspi isn’t exactly a Ferrari. :) It also measured temp and humidity at the Raspi with a DHT11. I don’t mind sharing the stuff but I’m not writing a great big document about it. I can load the schematics and source files as a bundle soemwhere if you are interested enough to wade through it. It is big, the PIC was a 12F635 and it has something like 6 bytes left and it is written in assembler so that is one big assembler file.
I have an IO account but never figured out how to do anything with it. hackaday.io confuses the hell out of me I can never find the same place twice on it. :)
So, it’s http://openenergymonitor.org/emon/ ?
I don’t know how common it is elsewhere, but in Finland, Helsingin Energia (power company), has installed smart meters for a while now.
With it you can follow your energy consumption via their web service, it looks like this: http://pasteboard.co/2qA8DzCk.png.
I think they mainly did it first so that now they don’t have to send anyone to read the meters once a year, because this is the same exact data they use to charge you.
In the UK most electricity suppliers will give you a monitor. The Current Cost one has a serial port so there are some web pages about getting the data out.
Not sending a meter reader does not save them much and it never will because in most places there is a legal requirement to inspect the meter periodically. The meter reader satisfies this but even reading remotely they will still have to send someone out occasionally.
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