
Long-range communication with devices that consume almost no power - sverige
http://www.washington.edu/news/2017/09/13/uw-team-shatters-long-range-communication-barrier-for-devices-that-consume-almost-no-power/
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andrewflnr
We need to talk about the security implications of low-power devices
broadcasting data. I cringed when the article talked about broadcasting
"medically relevant data" for kilometers, in the clear. That's not OK.
Everyone needs to be clear on the fact that that's not OK.

I'm ecstatic at the possibilities this has for reducing the power cost of
communication[0]. Please use the savings on some (at least half-decent)
crypto.

[0] Seriously, can this work for a consumer handset communication network?

~~~
andrepd
Encryption is a easy. I doubt this will be a problem.

~~~
andrewflnr
Encryption is easy on platforms with plenty of power and transistors and well-
established libraries, which are the exact opposite of what we're talking
about here. Encryption on very low-powered systems is a well-known problem.

~~~
boznz
Encryption for low data rate systems is actually a very easy problem. I have
sensors in the field which transmit a 64 byte package once a day only 18 bytes
of which is data and is encrypted. the encryption an one time pad in ROM which
lasts the life of the device (8 years) the device does not receive.

I agree encryption is totally necessary for medical/sensitive data or two way
devices but for other cases (such as irrigation data) no encryption or an
encrypted ID is just fine and a problem that does not need to be solved.

~~~
forapurpose
Seemingly trivial data can be combined to form a detailed picture of someone.
Regarding irrigation: How is the farmer's business doing? What kind of seed
are they using and what is their schedule? Is the homeowner home? Are they
following local water use laws or guidelines?

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eutropia
I'm concerned with the environmental impact of:

"...farmers looking to measure soil temperature or moisture could affordably
blanket an entire field to determine how to efficiently plant seeds or water.
"

Littering chips all over the place?

~~~
sapote
And largely these sensors are unnecessary. Such "precision agriculture"
efforts are just doubling down on a broken agricultural paradigm.

~~~
Sargos
What does that even mean? Plant seeds, water, temperature is just how nature
works. What other "paradigm" of agriculture is there?

Maybe you mean everyone growing their own food? That's not sustainable.

~~~
sapote
Two things:

* Sure, seeds germinate with water and warmth. But that's true today. In the words of an Australian farmer quoted in a research paper a few years ago: "Mate, we don't need a chip to tell us the soil's dry."

* There are other paradigms of agriculture that are actually sustainable. Agroecology is a good example of an alternative scientific paradigm for agriculture, one that thinks of agriculture in ecological terms.

~~~
macintux
I'm not convinced by the Australian farmer.

Microclimates are a thing. Water is not evenly distributed across any sizable
plot of land. Being able to tell where the water is (or more importantly
isn't) can surely help deploy resources more efficiently.

But, I'm a desk jockey, and hope to never, ever be a farmer.

~~~
ivan_gammel
You are right. I've been working a bit with the software for water management
(although related to measurements of humidity over the day). Local management
of resources does increase yields and sometimes just saves the crop.

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cstross
Wow, the old-time KGB would have _loved_ this:

[https://en.wikipedia.org/wiki/The_Thing_(listening_device)](https://en.wikipedia.org/wiki/The_Thing_\(listening_device\))

(A passive resonant bug presented in a gift to the US Embassy in Moscow in
1945, designed by Léon Theremin, ancestor of today's RFID devices.)

The _modern_ bugging applications don't even bear thinking about ...

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ryanmarsh
I didn't see Mhz one time in the article and frequency only once with no
numbers.

2.8km... is that line of sight?

This article is beneath HN.

Link to the paper:
[http://longrange.cs.washington.edu/files/loRaBackscatter.pdf](http://longrange.cs.washington.edu/files/loRaBackscatter.pdf)

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tinix
You can't look at that trace antenna and guess the frequency?

Obviously it's ISM band, and these researchers are in the United States.

Does it really need to tell you that it's ~900MHz?

~~~
bsder
Yes, actually, it does.

The green PCB looks more like a 2.4GHz antenna to my eye. The epidermal patch
is much longer so looks like 900MHz to me. And there is also 27MHz for ISM.
The lower the frequency, the further it tends to go.

[https://en.wikipedia.org/wiki/ISM_band](https://en.wikipedia.org/wiki/ISM_band)

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j_s
dupe-ish: _LoRa Backscatter [pdf]
|[https://news.ycombinator.com/item?id=15201692](https://news.ycombinator.com/item?id=15201692)
(1 day ago)_

> ac29: _900MHz is heavily used in the US and describing the noise as
> "background" or "random" is disingenuous at best._

> Nelkins: _There has been some prior work on this:_

> junkcollector: _Active RFID. The same technology in any meaningful sense._

\--

related: _LoRaWAN packet received at record distance of 702 km
|[https://news.ycombinator.com/item?id=15201692](https://news.ycombinator.com/item?id=15201692)
(7 days ago)_

> aw3c2: _From a balloon in almost 40km altitude._

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ColanR
That's the same link twice...did you mean to post two different HN links?

~~~
j_s
Oops, my bad -- the first link to the dupe should have been:
[https://news.ycombinator.com/item?id=15246659](https://news.ycombinator.com/item?id=15246659)

Thanks for double-checking. Serves me right for trying to be helpful on my
phone!

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tomxor
This stuff has some really cool implications but...

> For example, flexible electronics — from knee patches that capture range of
> motion in arthritic patients to patches that use sweat to detect fatigue in
> athletes or soldiers — hold great promise for collecting medically relevant
> data.

Sorry this just sounds lame, whenever people try to suggest applications of
new technology they almost always seem to be A) not particularly useful and B)
unimaginative.

> sweat to detect fatigue in athletes.

Really? don't you think it might be simpler, faster, cheaper (better in every
single way) to just _ask_ them?

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celim307
To play devil's advocate, there definitely is a disconnect between when you
think you're fine and when you're dehydrated

~~~
kazinator
It took me some 15 years to realize I had been chronically lacking sodium.

Fixed that problem; running is better than ever.

Sometimes you know you're not fine, but the cause isn't obvious. An athlete
who is dehydrated might feel something is off, but not pin it on dehydration.
Maybe just a bad day, or not enough sleep, or recovery from some earlier
workout or whatever. That's a problem: even if the body tells you something,
the message isn't always interpreted right.

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neoh
Some Standford students seem to have done something quite similar already.
[https://web.stanford.edu/~skatti/pubs/sigcomm15-backfi.pdf](https://web.stanford.edu/~skatti/pubs/sigcomm15-backfi.pdf)

~~~
jotux
That paper is referenced in the paper cited in this article. Number 52:
[http://longrange.cs.washington.edu/files/loRaBackscatter.pdf](http://longrange.cs.washington.edu/files/loRaBackscatter.pdf)

~~~
anonymousDan
The Washington guys are definitely the leaders when it comes to backscatter
stuff.

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ColinWright
I'm late to the party, I've been doing work instead of keeping up with HN, but
this was discussed yesterday:

[https://news.ycombinator.com/item?id=15246659](https://news.ycombinator.com/item?id=15246659)

~~~
sverige
Oops, hadn't seen that! Didn't mean to double-post, and the original title was
too long so I had to modify it.

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grandalf
Finally something that might create a commercial incentive for a lowered RF
noise floor!

