
WISP: Battery-free computer that can be reprogrammed wirelessly - Jerry2
http://www.fastcodesign.com/3059141/this-battery-free-computer-sucks-power-out-of-thin-air?
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beambot
It's important to understand the difference between UHF RFID (this technology)
vs. others like BLE.

UHF RFID tags harvest all of their operating power from a reader's transmitted
RF signal. Multi-access is handled at the protocol layer via probabilistic
time-division multiplexing. The tag doesn't actually "transmit" \-- rather, it
is a cooperative radar target that reflects RF power back to the reader (sort
of like an SOS mirror) by intelligently, electronically changing its radar
cross section. The tags contain a single IC, and the antennas (for commercial
ID-only tags) are roll-to-roll printed... to the tune of Billions of tags per
year. The net effect: Tags cost around $0.10 each in volume. The read range is
practically limited to around 20 feet, as dictated by FCC limits on the
reader's RF output power (1Watt). Nominally, gen2 UHF RFID tags operate at
bitrates up to ~500kbps, but there are some specialized tags that can transmit
at 100Mbps using just a few microwatts (we used them to transmit dragonfly
neural signals during flight!).

Meanwhile, BLE technologies can do push notifications, mesh networking, and
the like. The beacon (tag) may contain a full TX-RX transceiver. However, due
to the tight spectral requirements of their transmissions, they generally
require an external (off-IC) crystal oscillator. The net effect is that BLE
beacons are more costly -- on the order of $2-3 ea. This means that they are
much less likely to be used to tag everyday items (like a carton of milk) or
deployed in the billions for outdoor monitoring.

Source: I'm an expert on these systems as applied to robotics, healthcare, and
remote sensing [1,2,3,4]. I'm giving a talk on them next week at IEEE RFID /
RFID Live. Oh, and you can also buy WISP-like tags from a company called
Farsens.

[1] [http://www.travisdeyle.com](http://www.travisdeyle.com)

[2]
[http://www.travisdeyle.com/research.html](http://www.travisdeyle.com/research.html)

[3] [http://www.hizook.com/blog/2015/08/10/mobile-robots-and-
long...](http://www.hizook.com/blog/2015/08/10/mobile-robots-and-long-range-
uhf-rfid-sensor-tags-internet-things)

[4] [http://www.wired.com/2013/06/dragonfly-backpack-
neuron/](http://www.wired.com/2013/06/dragonfly-backpack-neuron/)

~~~
joshu
I have been meaning to research this stuff for a crazy automotive application
I have in mind. thanks for the pointers.

(Ps hello fellow TR35er!)

~~~
beambot
Hi Joshua -- wow, small world! Feel free to ping me (email in profile). I'm
happy to chat about sensing or robotics...

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derefr
When I clicked through, what I was hoping for was an e-ink tablet without the
battery, where you have to hold it close to an inductive charging surface each
time you flip the page.

Such a thing sounds stupid at first blush, but in combination with ubiquitous
inductive charging mats (imagine them on e.g. every desk in an office), it
could make for _extremely_ cheap, thin and light e-ink devices—to the point
that they start being more like documents than readers: flimsy laminated
'paper' sheets that happen to be able to update themselves.

Heck, if you didn't expect to use them outside of the installation (if they
were for displaying internal manifests in a warehouse, or patient charts in a
hospital, etc.) then you could externalize _all_ the "document reader"
electronics, and just make the device into a dumb framebuffer that hardware in
the mat can push images to. (Though you might not _need_ to do this; we can
fit some pretty complex logic inside e.g. a credit card, so we might be able
to fit all the storage+firmware chips for a full e-reader inside a piece of
paper without that making it less piece-of-paper-y.)

~~~
beambot
You mean... like this: [http://www.alansonsample.com/research/NFC-WISP-
Eink.html](http://www.alansonsample.com/research/NFC-WISP-Eink.html)

~~~
roywiggins
I just want someone to put e-ink displays on hard drives so I can stop
labelling all my loose drives with sticky notes.

~~~
Wingman4l7
The closest I've seen to this is a thumb-drive with an e-ink "capacity meter"
in the casing, made by Lexar starting back in 2006.

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baggachipz
> "Imagine if your wallpaper could run apps"

Uh. No thanks.

I think the technology has some great potential, but why does every tech
article have to dumb everything down into some iPhone analogy?

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userbinator
Probably more like, "Imagine if your wallpaper could listen to you"

Even the name of the device, Wireless _Identification_ and _Sensing_ Platform,
sounds rather creepy.

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njharman
But I want my house to listen and sense me. The advantages far outweigh
worries. Besides what makes Big Brother isn't the existence of surveillance it
is the lack of control over it, who uses it, and how. So fight for open
source, transparency, end of advertising/marketing. Not against technology.

I want my house to know what room I'm in (for lights, environment, music
following, to adjust temperture when I'm active or too hot, to answer alexa
like queries, to announce alarms reminders, to tell me the kitchen is hot and
smokey cause I forgot beans on stove, to give me alert someone pulled into my
drive, stopped in front of my house, to call 911 if my heart stops.

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_wmd
Is there any practical limit to how much energy a device like this can buffer
before springing into action? I'm just curious if it would be possible to
quickly leech enough to power a peripheral like a solenoid, or at least ensure
enough energy is available to complete whatever computation the device is
intended to perform

(Vaguely imagining a completely unpowered electronic lock, and a handheld
'key' that I guess would contain a fairly beefy battery)

~~~
gh02t
> Vaguely imagining a completely unpowered electronic lock, and a handheld
> 'key' that I guess would contain a fairly beefy battery

That's a good idea, actually. I dunno about this technology specifically, but
there are wireless power standards that can transmit more power, e.g. Qi can
provide 5W at a up to 4cm according to Wikipedia. That should be plenty
suitable for a lock I'd think.

It'd be even cooler if cell phones could _transmit_ power wirelessly, but
AFAIK phones with inductive charging hardware can only receive. If they added
the ability to transmit, suddenly your phone's battery could become a sort of
universal power source for talking to various passive devices like locks and
stuff.

Though, this is slightly different from what's described in the article. If
I'm understanding it correctly, this thing is harvesting its power from a
standard RFID signal, so you don't need any special power transmission
hardware. No way would you be able to get enough power out of it to power any
kind of mechanical actuator for a lock.

~~~
reacweb
Instead of battery, you could turn the key inside a mechanism that would
produce the energy needed to open the lock ;-)

~~~
gh02t
True, but an electronic lock has lots of advantages over a mechanical one.
Especially for a business, you can trivially grant and revoke keys as well as
track access. I feel like in principle they could be more secure too as all
but the fanciest of locks are pretty trivial to pick, though that's predicated
on somebody building an electronic lock without
hardware/software/cryptographic flaws (good luck).

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detaro
"battery-free computer" = fancy word for RFID tags with a programmable CPU

~~~
thrownaway2424
Like every contactless smartcard ever.

For that matter my iMac is a battery-free computer that can be programmed
wirelessly.

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colehasson
I worked with WISP in school. My contribution was demonstrating the platform
providing sensor data from inside a chemical reaction vessel.

Also, this was the first hardware project I worked on where the community used
a wiki as the primary communication and it worked! Kudos to Intel

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dave2000
Is battery research stagnant? I thought it was a hot area of research with
great potential profits for new ideas.

~~~
icebraining
The linked article claims the current commercially available batteries have
been stagnant, not the research, which is quite active but is only expected to
bear fruit in the medium term.

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nickpsecurity
I'd rather have one of these that has a tiny, lithium-ion battery that it
barely uses. Makes much more sense with the same applications. When done, you
either plug it into a charger or (more homebrew) take the battery out to plug
_it_ into a charger. Regardless, I see a tiny battery getting better results
than sacrifices made to be "powerless."

Now, what's the smallest PC you all know that can run for a long time and with
some useful work on a tiny, lithium-ion battery? That would be interesting.

~~~
tluyben2
I was going to ask that, but for me it doesn't have to be a PC. We work on
pretty low power electronics at work, but it is very hard to figure out what
the best combination for practical hobby electronics would be. So like what
kind of MCU, radio and display would consume the lowest power while still
practical enough for me to have fun with. That would mean the MCU has to be
10+ mhz and the display needs to be at least file of a smaller smartphone.
eInk would work.

It could be combined right? Very tiny low power lithium ion with inductive
loading in some way that is efficient and easy enough.

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icebraining
The original project's page:
[http://sensor.cs.washington.edu/WISP.html](http://sensor.cs.washington.edu/WISP.html)

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homero
So I'll need a rfid coil aimed at my wallpaper? There's much better technology
for this, it's not power source free

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shkesar
Forget fitness taker, smart watch and tiny little things. I'm thinking thin
smartphones. If one of these can be powered by multiple RFID signal sources.
Do the math for required power signal strength and get working around the
limitations.

~~~
Someone
That will not work out. Even ignoring the elephant in the room that is
powering the display, a smartphone communicates wirelessly over hundreds of
meters.

You will never get that much power from RFID readers in any practical setup
(if you're McGyver, a setup with thousands of readers, if not way more, and a
few square meters of antenna might 'work', for a loose definition of the word)

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calgoo
Wow, they could not use a different acronym from WISP? I guess wireless ISPs
are loosing business to Fiber etc, but still. From a quick google search, it
would be better to call it WSIP.

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hanniabu
Pretty interesting, I'm assuming you have to be near the chip to access the
data, considering it's based off RFID tags?

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martin_henk
Development unit can be purchased from the developers for ~300$ btw

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arjun1296
Click-bait.

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dang
We changed the linkbait title to representative language taken from the
article. If anyone suggests a better title we can change it again.

~~~
dmritard96
Reprogrammable RFID Tag...

