
Want to Know What's Happening in a Building? Listen in at the Breaker Box - teklaperry
http://spectrum.ieee.org/view-from-the-valley/energy/the-smarter-grid/want-to-know-whats-happening-in-a-building-listen-in-at-the-breaker-box
======
joezydeco
In the Chicago suburbs the local electric utility (ComEd) has been installing
smart meters on residences over the last couple of years. I got mine about 18
months ago.

The meter is Zigbee-capable, so I went out and got a utility-approved gateway
to read the meter (the meter allows access only to approved MAC addreses) The
Rainforest Automation RAVEn cost me about $50 (it might be discontinued now)

[http://rainforestautomation.com/wp-
content/uploads/2014/02/r...](http://rainforestautomation.com/wp-
content/uploads/2014/02/raven_datasheet_1.8.pdf)

There are a number of things you can query from the meter, but mainly you can
read the current demand every 4 seconds down to about 10 watts resolution (the
Verdigris device is claiming 5-Watt resolution). It's all in a tidy XML format
with a published API spec.

Long story short, you can play with some of this stuff on your own right now
in certain parts of the world.

~~~
toomuchtodo
What was the approval process to get the Raven device whitelisted for access
to the meter?

(I own a Condo in Schaumburg)

------
dom0
> “We shrunk the sensors and got high fidelity signals,” Chung says, “by
> figuring out novel ways to fit more powerful sensors into tight spaces.”
> Some of that had to do with the arrangement of the magnetic material, he
> says, but can’t say more until patents are filed.

Which is interesting. I guess the main component here is manufacturing cost,
since very small, very high capability probes exist since the ~60s. E.g.
Tektronix has had small probes with 50-100 MHz [which is orders of magnitude
wider than you'd need for this] bandwidth since then.

~~~
jerryr
It's cost, size, and regulatory. Existing current probes that are magnetically
coupled and thus don't require an electrical connection to the mains (which
would be a safety/regulatory nightmare) are big: [http://www.tek.com/current-
probe](http://www.tek.com/current-probe)

~~~
dom0
A small probe, like the P6021 (which I own [0]) is pretty small. The
transformer itself is tiny; there is only a small PCB in the handle with some
frequency compensation. (However it is said that these are difficult to
manufacture - more so for their Hall-enhanced partners - due to the precisely
ground halves of the core).

The bigger probes that are meant to go on bare, live bus bars and such are
probably mostly air to give the operator the required safe handling
distance... probably not an issue for a clip-on probe that goes on insulated
wires?

[0] Technically a P6021 sold to Philips who bundled it up with a matching
amplifier of their own design.

~~~
jerryr
That probe is pretty small, but keep in mind that many of these need to be
tucked into existing circuit breaker panels while maintaining certain
clearances for regulatory reasons. They also need to be easy to install for
safety and product adoption reasons.

I think we are saying similar things though. I worked on this project with
Verdigris (though I was not personally responsible for the design of these
probes) and, to your original point, the challenge is fitting these at a
reasonable cost while achieving the desired accuracy. I guess I'm so used to
low manufacturing costs being a given that I tend to focus more on the other
aspects of the problem.

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graton
This sounds a lot like [https://sense.com/](https://sense.com/)

There was an episode of This Old House about it:
[https://www.youtube.com/watch?v=HZft4qoK7Ds](https://www.youtube.com/watch?v=HZft4qoK7Ds)

~~~
thatwebdude
It's very cool, was brought hip to it from TOH.

I've watched a few reviews and videos on it; definitely considering it.

I especially like the diagnostics part of the equation; which is still an
algorithm quite in beta.

Beware, their AdSense is strong. It'll follow you forever.

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malandrew
Nice. I would love to see something like this for water too, although Without
magnetic signals to sample, I'm not sure how it could be done. My girlfriend
had a water bill twice everyone else's in the building and the problem ended
up being a toilet that was leaking silently.

~~~
kimburgess
Sounds super similar to some of the research out of (The University of
Washington UbiComp
Lab)[[http://ubicomplab.cs.washington.edu/publications/](http://ubicomplab.cs.washington.edu/publications/)]
back in 2010. There was a project led by Shwetak Patel, that ultimately turned
into
(Zensi)[[https://www.crunchbase.com/organization/zensi](https://www.crunchbase.com/organization/zensi)].

Basic premise was to use some DSP to detect electrical noise emitted via
various appliances and extract usage patterns from this. The same approach
could then be used for water and gas systems by detecting pressure, rather
than voltage fluctuations.

From what I can tell this seems to have now just been consumed into the depths
of Belkin.

~~~
staticfloat
Amazingly, I can actually speak to this. I'm Ph.D. student in Shwetak Patel's
lab, and yes, this looks to be extremely similar to the ElectriSense [1] work
done by Sidhant Gupta (now at Microsoft Research).

The water analogue was Eric Larson's Ph.D. work, and was much more difficult
from a DSP perspective due to two separate issues:

* When water is flowing without turbulence (laminar flow) it doesn't leave much of a signature on flow or pressure sensors

* Any kind of signature that does exist is often changed significantly depending on the network of pipes that stand between the single point sensor and the source of the water event.

For these two reasons it took a while for us to work out a high enough
accuracy for the water stuff (in the end we used a water pressure sensor
plugged in close to your water heater as a fairly central point that most
people can access easily) and that was published as HydroSense [2]. We like
our *Sense names. :P

HydroSense was indeed bought up by Belkin, and they are pushing it forward in
a way that we just cannot do in academia, so that's a good thing. ElectriSense
I don't remember exactly what the IP status of it is, but I do know at least
one student was working on some interesting extensions of it that may be
published in the next year.

[1]
[http://ubicomplab.cs.washington.edu/publications/electrisens...](http://ubicomplab.cs.washington.edu/publications/electrisense/)
[2]
[http://ubicomplab.cs.washington.edu/publications/a-longitudi...](http://ubicomplab.cs.washington.edu/publications/a-longitudinal/)

------
mpeg
> "They then set about rewriting an algorithm they’d been researching at work,
> one designed to accelerate packet separation in chips, to apply it to this
> problem."

IANAL but are they not worried that Broadcom will sue with statements like
that?

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PhantomGremlin
Eventually the necessary monitoring circuitry will be embedded into every
circuit breaker. Of course, there will still be a need for analytics; the raw
information from the breaker won't be sufficient.

------
Glyptodon
Uggh. Privacy nightmare.

~~~
dsfyu404ed
Ditto that.

