[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.

[m-p-3]

It's nice as long as your document fits on a single page. Otherwise you need several of them, and it won't allow you to scribble on it or highlight stuff.

IMO this is still less functional than an ordinary sheet of paper, this just solve the energy issue, but not much else.

I'd still probably go with a powered one just to get the benefit of swapping pages and taking notes on it.

On the other hand, if the can manage to make something that can power them over a longer distance than typical NFC, I could see those used for in-office digital signage (meeting room status and schedule, employee schedule, etc) which doesn't require a battery swap, PoE or some other kind of way to power it.

[arendtio]

Now I understand why the Stark Trek people used to have dozens of tablets ;-)

[doorbellguy]

The pricing should also play a significant role in its adoption. Especially if unbundled with other phones. At almost $42 and $70 (for the larger display) we should wait to see which subset of customers could justify it's use-case in daily life.

[p1esk]

Did you forget an extra zero or are they really this cheap?

[akiselev]

Yeah I had to do a double take. It's less than $80 before shipping.

https://www.aliexpress.com/item/4000748950835.html

[blisterpeanuts]

They're also for sale on Amazon for about the same prices.

[Cthulhu_]

Price tags, menus, or e.g. corporate announcements is the only thing I can think of really, but I'm not the most creative.

[shawnz]

I've seen a system like this used for price tags already at one of my previous jobs. The tags were e-ink displays that were updated wirelessly using a special tool.

[kwhitefoot]

Such tags have been used for years here in northern European supermarkets. Not sure how similar they really are though.

[rahimnathwani]

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

[hnlmorg]

You used to be able to stick a lot of text on a 320x200 display when I first got into software development. :)

Jokes aside, you'd probably want that 480x800 (portrait rather than landscape). Which would be 80 columns and 100 rows in old 8-bit microcomputer terms. So it wouldn't be the more detailed of a document but it should be detailed enough for a cheat sheet or narrowly focused reference page. You probably wouldn't want much more than that anyway otherwise you risk your reference material to be too verbose for quick sanity checks.

[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.

[catalogia]

I think you must be spoiled by modern high-dpi displays if you can't see any use for 800x480 displays. When I was in school I used to put cheatsheets on my TI-83+ which had a 96×64 monochrome display!

[pipework]

Smalltalk's syntax[0], presumably.

[0]: https://medium.com/@richardeng/syntax-on-a-post-card-cb6d85f...

[semi-extrinsic]

Isn't that the same as the OG Kindle? If so, you can fit approx half an A4 / Letter page at adequate readability.

[anigbrowl]

Lots of useful things would fit on that, and resolution increases with technological refinement.

[andai]

If you swipe two phones, you can double the resolution.

[z2]

I currently do something like this with a cheap thermal printer. Aside from apparent environmental issues of thermal paper, it is really great to print out these short, portable, and disposable materials on a whim from my phone (Bluetooth) and computer (USB).

[TheSpiceIsLife]

The reactant in thermal paper is often BPA.

Might pay to check yours and read the health effects section here https://en.wikipedia.org/wiki/Bisphenol_A

Edit: fixed a word

[rtkwe]

Couldn't tell but is BPA toxic on skin contact. All the worry I was hearing was based on ingestion.

[saurik]

Do a Google search for "BPA toxic skin contact" (search terms you came up with) and be amazed at the wonder of modern search engines (which will return results from PubMed, Nature, and WebMD).

(edit) There is something telling about how three people have now downvoted my comment for not doing the work of pasting the links myself, but not a single person has bothered to provide the links themselves, which kind of demonstrates the problem with these comments: the comment I am responding to is undermining a well-researched notion--one that AFAIK no one questions, and for which it is trivial to find numerous articles and studies: that BPA is absorbed through the skin from receipts--with the moral equivalent of "citation needed"; that comment asking for a reference seriously took longer to type than finding the relevant articles would have, and yet in practice is asking other people to do that work, and so the work doesn't get done by anyone... but the comment itself sits there, making people who are less informed on the topic question the validity, as in "I dunno, this comment claims they hadn't heard that, and is demanding citations; if it were easy to find a citation they wouldn't be asking that, so I guess the thing they are poking at isn't actually true". If you want to downvote my response to that behavior--which is to point out that a Google search would have worked--but you aren't willing to actually do the work of providing the links yourself (or at least also downvoting the comment), you are just making yourself part of the problem of incentivizing leaving these misinformative comments :/.

[mrexroad]

I say this to be helpful, so please don’t take it as an attack. While initial comment added no value (e.g. that Google exists), but what I found off-putting was your tone. That, coupled with the comment[0] in your profile, make it easy to jump to a specific conclusion, right or wrong, about your intent. just be mindful of perception. FWIW, I struggle with this daily and often wish more folks would point out when I’m coming across in a way I didn’t intend.

[0] “I make it something of a policy to not look at things people say in response until at least a month later.”

[DenisM]

You are being downvoted for being snarky, which is against the HN guidelines.

[perl4ever]

You are being downvoted for commenting on voting, which is against the HN guidelines.

[WalterBright]

> The reactant in thermal paper is often BPA.

Too bad. The original "invisible ink" activated by heat is lemon juice.

[TheSpiceIsLife]

I heard this before, but how does that knowledge help with dealing with BPA exposure now?

[WalterBright]

Obviously, it doesn't. But the knowledge of lemon juice is something you can pressure your thermal printer vendor with.

[int_19h]

Or milk.

[ako]

The only times i use a printer these days if someone else wants me to deliver something on paper, not for myself. ePaper is just as unacceptable as digital on phone. Last time was to have a paper copy of a india e-visa.

[numpad0]

These type of E Ink devices takes seconds to update

[codetrotter]

I don’t mind. Printers often have a startup time of multiple minutes. And with printers we waste paper and we are required to refill them with ink or toner.

I will gladly use this e-Paper display instead in any situation where I want some kind of reference sheet like the parent commenter said, and where the resolution is sufficient.

[jandrese]

Refresh time is listed as 4 or 5 seconds, depending on how big the display is.

[datashow]

But no color, and no real gray scale.

[eyegor]

You can simulate grayscale with dithering, similar to drawing with a pen or pencil. If you really need grayscale or color you can buy eink displays that support it, even ones up to 300ppi. I don't know if 1w would be enough to power them though, and they're a bit more expensive.

[ben-schaaf]

Considering these types of displays don't require active energy input to function, I don't see why you couldn't update any size display with 1W. You'd need to progressively update parts of the display at a time, which likely requires extra engineering effort, but in theory it should work.