
4.2″ and 7.5″ NFC-powered e-Paper Displays Work without Battery - homarp
https://www.cnx-software.com/2020/03/17/nfc-powered-e-paper-displays-work-without-battery/
======
jobseeker990
This could replace your printer really nicely. Anytime you want to print
something out, you swipe your phone by this and use it instead.

Any kind of reference, recipe, directions, notes. This would even be cool
instead of a second monitor. Just to put up a reference page or cheat sheet.

~~~
rahimnathwani
The resolution is only 800x480. What reference page or cheat sheet would fit
on that?

~~~
lukifer
I'm always surprised that e-ink readers have such good readability at low
resolutions. I think an accidental by-product of how they work is a little
"fuzziness" when translating from digital data to analog atoms, so the text
looks more like organic newspaper ink than a pixellated screen.

Anyway, most e-readers are in the ballpark of 800x600; and I expect if the
concept got traction, there's no reason it couldn't be scaled up to 8.5" x 11"
at equivalent pixel densities (at the cost of hovering your phone for a few
seconds longer or whatever).

~~~
yencabulator
> Anyway, most e-readers are in the ballpark of 800x600

A Kindle Paperwhite is 1072x1448, 300 PPI, 16 levels of grayscale.

I personally couldn't tolerate reading on a kindle until they reached 212 PPI.
800x600 may be acceptable for a simple sign, but it's not gonna wow anyone.

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hadlock
Would be interesting for use on a boat. Generally you want a fast refresh rate
but once a minute would be fast enough for most users. The problem with
navigation displays on boat are

1\. daytime visibility 2\. long term waterproofing in a saltwater environment

With this setup you could mount a raspberry pi W on one side of the fiberglass
to interpet NEMA 2000/0183 data and the NFC chip, and the waterproof,
hermetically sealed e-ink display on the other, held on with velcro or
neodymium magnets etc.

~~~
mycall
I've gone through multiple RPi on my boat. Maybe if I epoxied the board it
would have a chance.

~~~
londons_explore
Most epoxy isn't very flexible, and cracks leading to leaks over time.

For something you can do at home, try heating the whole thing to 120C and
dipping in hot glue.

~~~
hanniabu
Idk about new hot glue, but I have some old projects with hot glue from about
15 years ago and it's starting to dry out and crack. Something to keep in mind
if looking for longer term.

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akincisor
It would be a good choice to replace tablets that are used outside conference
rooms to show the schedule and/or book the room.

~~~
EvanAnderson
If you could parasitically power the unit from Wi-Fi beacon frames that would
be _awesome_. The idea of a sign that "magically" updates itself over the air
gives me a giddy "I live in the future" feeling.

~~~
jodrellblank
WiFi -> electric current rectennas announced a year ago[1] were in the range
of 40 microwatts, and the blog post says this NFC system runs at 1.4 Watts,
that feels a long way away. But years ago LCD calculators could run on a solar
cell the size of a finger and powered by ambient room lighting - surely must
be some close to crossover level available.

[1] [http://news.mit.edu/2019/converting-wi-fi-signals-
electricit...](http://news.mit.edu/2019/converting-wi-fi-signals-
electricity-0128)

~~~
Smoosh
I'm wondering if that was a constant 40 microwatts, and if that could be
stored in capacitors so that every 4-5 seconds (the refresh rate of the panel)
there would be enough energy accumulated to power the circuitry for an update.

~~~
eyegor
Yes is the answer, but it would be much slower. Assuming 1w for 6 seconds (4s
refresh + 2s transfer), it would take about 42 hours for a lossless storage +
regulator circuit. 40uw is an incredibly small amount of power.

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vitovito
Open source code to write the image using libnfc and node.js 8.x:
[https://gitlab.com/bettse/wne_writer](https://gitlab.com/bettse/wne_writer)

~~~
rajlego
Does it not work with standard NFC libraries?

~~~
vitovito
Like contactless payments, it uses NFC (the protocol), not NDEF (the data
format) to write the image. You're not writing the image as an NDEF message,
so NDEF-only systems (like early iOS support or WebNFC) won't be useful.

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eyegor
Many people on this thread are complaining about the poor performance of this
passively powered screen. PSA if you care about resolution and speed, and
don't mind powering it; pick up the ED060KC1 panel. 300ppi 6" panel for around
$75, base refresh is 450ms. If you're brave, it seems mostly stable down to
300-350ms. It's the same panel most high end ereaders use.

~~~
junky228
when I looked it up I was finding listings for at least $150, what sellers are
you getting the $75 estimate from?

~~~
eyegor
Aliexpress/eBay market prices. You can even get them cheaper than that, it's
just that $75 is more available.

[https://m.aliexpress.com/wholesale/ED060KC1.html?keywords=ED...](https://m.aliexpress.com/wholesale/ED060KC1.html?keywords=ED060KC1)

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peter_d_sherman
Excerpt:

"e-Paper displays have great readability under sunlight, and only consume
power when updated. But their refresh rate is limited, and most displays are
fairly expensive."

I've been searching for a tiny computer / screen combination that would work
under absolute minimal power; that is, if you were in deep space (or in the
deep wilderness), and only had a small (say, 5W or less) solar panel for
power, then what tiny computer / screen / keyboard combination would you use?

Well, this screen seems like it might be ideally suited to be the screen
component of a setup like that...

~~~
robocat
Jailbreak a kindle. They are super low power and cheap with lots of features -
I’m guessing a 5W solar panel would be overkill if you only update the screen
irregularly.

~~~
e12e
On that note... The remarkable sipposidly allows access for writing software
(I think their dev documentation leaves something to desired..). Might also be
an option.

Ed: [https://remarkable.engineering/](https://remarkable.engineering/)

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ddevault
If this can be made thin and small enough, it'd be cool to use it to put your
remaining balance and perhaps recent transactions on transit cards.

~~~
jv22222
Let's talk that through a bit more.

I wonder if it could be used to create one-off cryptographic notes - that,
when used (scanned), are somehow deleted and can never be used again.

Can't think of a way off the top of my head, but I wonder.

~~~
arkh
[https://www.gemalto.com/financial/cards/payments/dynamic-
cod...](https://www.gemalto.com/financial/cards/payments/dynamic-code-
verification)

Already used to make dynamic CVV codes for cards which change every 30
minutes.

~~~
jv22222
That’s cool

------
candeira
If I worked at Waveshare, I'd partner up with a phone case manufacturer and
sell user-customisable phone cases.

They could also offer a SDK so apps could publish high utility info with low
update frequency on the case itself: weather, public transport realtime
schedules, etc.

(Edit: had originally written "low-latency" instead of "with low update
frequency", because of the strong conditioning to associate "low latency ==
good")

~~~
kabacha
Seems to be a bit thick for a case at 1cm thickness [1] + it would probably
need a screen protector itself.

1- [https://i.imgur.com/dY1YHkU.png](https://i.imgur.com/dY1YHkU.png)

~~~
candeira
Yes, for now it is, but it's also stacked so it looks like it's "all screen".
Maybe if you could spread components around, it could be thinner.

~~~
alex7o
Somebody else commented this:
[https://www.gemalto.com/financial/cards/payments/dynamic-
cod...](https://www.gemalto.com/financial/cards/payments/dynamic-code-
verification) I suppose if you can fit it inside of a credit card it would fit
a case, and it would be really cool.

------
WalterBright
Oh, I wish it came with a USB NFC device so I could send it an image from my
desktop. Not sure what I'd use it for, but at that price point I can figure
something out :-)

I've always been highly annoyed that I cannot set the screensaver on my Kindle
to "the last page I read". Then I would set it to things like my itinerary
when I travel, to an editor cheat sheet when I'm learning an editor, etc.

~~~
kumarvvr
Found this one.

[https://www.evelta.com/er302-high-frequency-nfc-writer-
usb/?...](https://www.evelta.com/er302-high-frequency-nfc-writer-
usb/?gclid=Cj0KCQjw6sHzBRCbARIsAF8FMpXIikW8oKpfY_yYlVV6Ovz8W0z2d0SCl5JNmHLuYwzVjHCUzW1Mx0IaAhuvEALw_wcB)

------
philips
I think Chrome 81 has WebNFC too [https://googlechrome.github.io/samples/web-
nfc/](https://googlechrome.github.io/samples/web-nfc/)

~~~
Namidairo
Yes, but this particular board uses the low-level i/o that are mentioned as
not supported.

That said, IF the board firmware was open, you could probably get it to speak
NDEF if you were willing...

------
kohtatsu
Clicking "Read More" on the cookie banner sends you to Google for "How to
remove cookies."

No, I want to set a cookie to tell y'all not to set tracking cookies and just
limit it to strictly necessary ones.

I can remove them and their server will go ahead and set them again.

And no, sending me to a property owned by one of the worst offenders in this
space is not what I want.

------
timw4mail
These look similar to the ePaper price tags I've seen starting to pop up

~~~
remcob
I wonder if the same app will allow updating those.

~~~
fraidy-cat
I would hope that electronic price tags make use of some sort of
authentication in order to set the price that they display.

In Norway, where I live, big retailers will often allow you to pay the price
that is shown on the shelf even if their cash register is returning a
different, higher price.

I have personally experienced a difference between shelf price and cash
register price a few times, and in all of the cases where this happened at a
big retailer they allowed me to pay the shelf price.

I actually thought that they were required to do this by law, but looking into
it now I find that it is only a recommendation that they do so and not
something that they are required to do by law.

The Norwegian Consumer Ombudsman (the government-appointed ombudsman in Norway
for consumer affairs [1]) has an article on their website about this topic
[2]. Translated from Norwegian, here is an exceprept of what they say:

> * Do you have the right to buy the item at the price at which the item was
> marked? The Marketing Act does not grant such rights, and it is disputed to
> the extent that one has a legal right on other grounds to demand the
> purchase of the item at the shelf price.

> * The stores should still allow the customer to pay a shelf price. It is the
> store that made the mistake, and it would be very bad service to allow for
> this to negatively affect the customer who notifies them of the error so
> that they can correct it.

Anyway, as mentioned you will often be allowed to pay the shelf price rather
than the cash register price when you're at one of the stores of the larger
retailers. So obviously it would be bad for their business if someone was able
to manipulate the price tags without them noticing it.

In closing I should also note that there are probably limitations to how big
of a difference in price that they would be willing to accept. In my case it
has often been a matter of $20 in difference at most. So, don't expect that
you would be able to pay like $99.50 for something that was supposed to cost
$995 or anything like that, even if the shelf price somehow ended up showing
$99.50 :P

And also, any consumer that changed the price-tags of the things they were
buying in order to con the store into selling it to them at a lower price
would see no sympathy from me when they inevitably eventually got caught for
doing so. Remember, kids: Just 'cause it's technically possible don't mean you
are legally allowed to do it. If you notice a vulnerability in a system I
strongly recommend that you don't touch it and that you at most let them know
about it anonymously unless you have prior written consent to investigate
and/or mess with the electronic systems that belong to other people,
businesses or other kinds of entities.

[1]:
[https://en.wikipedia.org/wiki/Norwegian_Consumer_Ombudsman](https://en.wikipedia.org/wiki/Norwegian_Consumer_Ombudsman)

[2]: [https://www.forbrukertilsynet.no/regler-for-prismerking-
buti...](https://www.forbrukertilsynet.no/regler-for-prismerking-butikk)

------
yingw787
Wow, this looks wonderful! It reminds me of my old solar-powered Casio
calculator. I have a Boogie Board already, but I can see how computer access
can change the game (accurate drawings, NFC to save, etc.). Hope to see these
guys around more!

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IanCal
Oh that's great. I wanted a nice, updatable eink screen for things like "this
weeks recipies" and have been trying to work out how to drive it / power it
without spending too much. A jailbroken kindle and a server somewhere could
work nicely, but there's a lot to that and I don't _really_ want to spend too
much time maintaining things.

Would be interesting to know if people have got it working with other NFC apps
/ how hard it is to add to your own app.

~~~
hirsin
I'd be happy with just taking a screenshot of the recipe and scanning it on to
the e-ink - this will save my phone quite a few run ins with oily/dirty hands
while cooking.

~~~
SamPatt
My phone screen locks quickly and uses a long PIN so it's terrible for
recipes. I've been trying to think of a cheap simple alternative.

------
nathancahill
This is really excellent. Various projects I've wanted to do with old iPads
all require a power source. Price is a little steep but hopefully lower in the
future?

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0xff00ffee
I'm really impressed they've got current requirements down to the level where
NFC can power the refresh. Geometry has to be the next step. When eInk busted
out of MIT in the late 90's, they kept revisiting flexible formats without too
much luck. I hope the flexible screen folks are cross pollenating with the
eInk brains. In this example, even though the display is small, the
electronics around it are very bulky.

------
fit2rule
Awesome! I'll be getting a couple of these for my sound studio .. these are
the ideal things to use to put up the daily recording schedule/sessions, plus
"RECORDING - QUIET PLEASE" type signs.

I've wanted to put an e-ink display up on the door for a while, but always
stumbled when it came to actually routing power to the door - but this just
elegantly solves the problem completely.

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eyegor
This could be great for a calendar or schedule at work, network a bunch
together and push updates whenever needed. Or weather forecasts. Or acting as
a live sign for reserving conference rooms, allow people to reserve on a web
portal or at the sign. For ~$100 (with a raspi or similar) this competes with
whiteboards.

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SebiH
I wonder if you could somehow get this to work with some form of passive wifi,
maybe slowly harvest energy from available radio signal to trigger a screen
update. Maybe someone knows if this is theoretically possible?

~~~
arendtio
[https://news.ycombinator.com/item?id=22610276](https://news.ycombinator.com/item?id=22610276)

------
DubiousPusher
Very cool. I love ideas that seem super obvious after you hear of them.

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edent
I wonder what sort of security it has? Wouldn't want anyone to be able to
deface it.

The photos make it looks like there's a micro-USB port on the bottom. Any idea
what that's for?

~~~
baybal2
Then, just undeface it.

~~~
edent
Doesn't help much if the display is in a public place like a supermarket.

~~~
reaperducer
I've seen e-ink price tags in grocery stores, and it doesn't seem to be any
more of a problem than someone writing over a paper price tag with a Sharpie.

~~~
frogpelt
But maybe more of a target?

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philips
Anyone find if the NFC protocol is documented somewhere?

~~~
jaclaz
>Anyone find if the NFC protocol is documented somewhere?

You won't probably like this (between 100 and 600 US$ per document):

[https://nfc-forum.org/our-work/specification-releases/specif...](https://nfc-
forum.org/our-work/specification-releases/specifications/)

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solarkraft
Just a tad too slow to be a cool e-reader.

------
RuleOfBirds
Why can't I navigate the world without running across hideous, overly
sexualized imagery of women at irrelevant, random times?

~~~
kabacha
If it stinks everywhere you go maybe it's time to look under your shoe.

Dude is some anime fan and boss told him to make a video demonstrating photos
so why not take a pic of his anime figure? You're overreacting to say the
least.

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sschueller
Not cheap (USD 42) but still cool [0]

[0]
[https://www.aliexpress.com/item/4000418859190.html](https://www.aliexpress.com/item/4000418859190.html)

~~~
jaclaz
It's roughly 10 US$/inch, and is not that there that many uses for the smaller
4.2" model, the US$ 70 for the 7" model is IMHO more than "not cheap", "rather
expensive".

I guess that for the "this week recipe" a more traditional printed paper
remains cheaper and more practical.

For "daily" or more frequent need of refresh, maybe it may become a valid
choice.

~~~
reaperducer
I see at least one good use for the smaller one: Price tags at a supermarket.

Instead of a team of clerks changing the labels for three hours at night, you
can have one guy do the whole store in that time. The savings in labor would
quickly make up for the initial expense.

~~~
bleuarff
I don't know where you live, but here in France I haven't seen a paper price
tag for years. Every chain store has been using e-ink tags for a long time.

~~~
com2kid
Only one of the grocery stores near me uses LCD price tags.

There is a constant hiss/buzz from the power and I presume they aren't OLED
because I can see the inconsistent backlight that goes out in places along the
strip.

Feels cheap and crappy overall.

