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Comment by crazygringo | Hacker News Reader

Is there any practical use for color ePaper yet though?

From my understanding, the technology is still limited to extremely low-saturation colors with extremely low contrast as well, see [1] for example photos and how the tech works.

It's certainly not ready for advertising -- instead of a vibrant color image, it looks like something printed on newspaper and left to fade in the sun for 5 years.

And color e-readers have significantly worse contrast than black & white ones, which already aren't great.

So if you truly need usable color, it seems like you're still always going to choose a traditional LCD/OLED display. Based on the fundamental limitations of the color filters used with eInk, I don't really see a future for it. At least not unless a new technology emerges that doesn't rely on using color filters on top of traditional black-and-white eInk?

[1] https://goodereader.com/blog/electronic-readers/color-e-pape...

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There's a grocery chain (Superstore, Canada) which has been using the small two color displays (black white red) for pricing. They use the tiny 2.7" e-paper screens and a TI cc2540 microcontroller to periodically update the pricing via some 2.4ghz signal (ok fine, I was curious so I stole one to take apart). Seems like a VERY expensive way to keep prices up to date. The BOM cost on one of those little guys has to be north of $10, and I would imagine that the vendor that sold them the system doesn't sell them at cost. Multiply that times thousands of products.... So yeah, people are using them, but it doesn't seem like a great system.

> Seems like a VERY expensive way to keep prices up to date. The BOM cost on one of those little guys has to be north of $10

That's nothing, even after markup and multiplying it around all the shelves, consider the wages you have to pay for people to go around continuously re-stickering everything. I'm pretty sure it would pay off in under a month and reduce errors... freeing staff to do more useful things. What i'm sure will _not_ be paid off in a month is the cost of integrating it into existing pricing systems.

However I think there is a more practical reason why it's not suited to most supermarkets: they are constantly moving things around due to different products coming and going and different parts shrinking and growing, so why bother with digital labels when you have to keep physically moving them anyway.

I've worked in retail and this is spot on. There are people who did practically nothing but update tags all day. And yeah, any change to the existing software is going to be the real issue. Everything they use is old.

The ones I've seen still need people going around to update tags. They have an NFC/RFID thing that powers that tag while it updates

What is the cost on updating paper label prices? There must be a payback vs. manual labour for these systems.

Typical supermarket with 60,000 SKUS;

$20 total cost per device

= $1.2m to outfit a store.

/$15 employee gross costs per hour

= 38 years of labour for one store....

Either the # SKUs would have to be lower, or the BOM smaller to justify this.

On the flipside consider the material cost of paper pricing tags, reduced risk of pricing error, ability to change pricing more rapidly, increased customer marketing/attraction.

I'd also imagine that removing this function from individual stores and centralising it would save a considerable amount of store management time.

You're also forgetting the ability for stores to execute "surge" pricing.

I'm not a fan of it, but that will certainly recoup that cost much faster.

How do you handle the case where a shopper picked up an item at a certain price but by the time they got to the cash register it had changed?

Charge the lower price at the register for 2 hours after changing the display price?

Only change the prices over night? (but unlike with employees you can reprice the entire store every night without any particular cost)

The customer probably won't notice and if they do they'll walk back to the place they found the item and find the e-ink price tag has a price that matches the till. If they some how dispute it further the business will just lie like a rug until a particularly pernicious customer takes pictures of the price tag and then argues with the manager.

The eventual outcome will possibly be a class action law suit and in a few years the customers can sign up to receive a gift card.

You can see similar behavior with the same company here: https://www.cbc.ca/news/business/loblaws-25-gift-card-class-...

easy, you just display both prices with a fat title 'Hurry up! Price will be 25% higher in 12 minutes"

If this doesn't exist already, it will soon.

This seems like a bad idea. If I own a physical store and you’re in it I don’t want to encourage you to leave quickly. I want you in there as long as possible putting things in your cart.

wouldn't this encourage people to buy fewer items?

But customers are so used to confusing pricing labels you could just make the old (cheaper) price say: "Discount: $x".

Also if you hook up the change to motion detectors where you know no one is in the aisle, then you can skip it altogether.

Could maybe be solved by adding some more technology (e.g. a barcode) that allows them to reserve the item at the current price, plus maybe some other kind of incentive.

Call me paranoid/cynical but maybe they are planning on a future system were they use the profile they have on you to calculate your preferences and buying power and update the signs on the fly when you're coming up to them.

Or maybe they are already doing that ... I said to call me paranoid.

Some online services are already engaging in price discrimination, though physical retail has greater limitations in communicating prices to individual customers. I think that removing price tags entirely would be necessary for full price discrimination in brick and mortar retail (or some similarly revolutionary step, like AR vision placing price tags on items). That's not to say it's infeasible, but other changes may be necessary first. For example, in an Amazon Go location, you don't need to check out the items at the end. Customers would still definitely want to know prices of items, but I could imagine them caring less about seeing price tags if they aren't checking out immediately after. I think another system that could help would be a partial or full subscription model, where the subscription price could be an opportunity for price discrimination.

Keep in mind that shelves must be restocked as well. Employees are putting their hands on most product's shelf space daily. Updating the prices while restocking seems like an almost negligible cost.

That said, I know some people that work in the grocery industry, and my impression is that the margins are tight enough that they do the math on EVERYTHING

In terms of their hardware cost and software development/wireless network, it's much more than just Superstore. Superstore is indeed huge but it's just one part of a much larger gargantuan grocery conglomerate, Loblaws.

https://en.wikipedia.org/wiki/Loblaws

they operate with other brand names for non-superstore-sized regular grocery stores, and the T&T markets which are their own market niche: https://en.wikipedia.org/wiki/T_%26_T_Supermarket

From observing the behavior of my local superstore it also appears they're using the eink price tags on shelf in conjunction with some sort of software for planning shelf space and inventory, so it has some value to them other than just the manual labor to change paper price tags.

Hey do you work in EE/Hardware? If so, would love to send you an email about a project I’m working on

I am not the OP but I do. I'd love to use small color e-ink displays for low power indicator displays on equipment I design. I only run into it with hand held battery stuff, so for stuff I plug in it's kind of a non-issue.

Feel free to visit my website and send an email if you think you've got something that we could work together to get into some of my clients' projects. If it makes the final product more compelling I'm definitely open to it, especially if it runs on trivial drivers that a low power microcontroller can handle.

I'd basically expect a display that works with a chip like a STM32WB (wireless integrated so makes sense to pair with a low power design). https://www.st.com/content/st_com/en/products/microcontrolle...

Of course fancy people have access to Qualcomm parts, so I understand if that's what you're aiming for. But if it's suitable for a bit less fancy of microcontroller chips and has a reasonable price I'd love to replace the literal LCD displays we're still stuck on because I guess it's 1996 in the realm of equipment prototyping.

I do as a side hustle/ passion project. I make a small single use board, about as complicated as an arduino.

But I am by no means an EE.

Do you have a link to your project page?

$10 BoM and the replacement costs attributed to curious nerds :)

> Is there any practical use for color ePaper yet though?

Years ago, the cafeterias at Microsoft switched from using regular signage for their menus to giant plasma TVs that showed a static image of the menu that had been there. The menu at some of the stations (but not all) did change daily, so there was some, slim, benefit, perhaps.

After awhile, they moved over to having a slide show on the screens that alternated between glamour shots of the food, and the menu. Now you could only see the actual menu for a fraction of the time, and despite being a speed reader, I'd often have to wait for the menu to come back around multiple times before I could read it all and decide what I wanted to eat that day.

But it sure did look modern!

Further irony, IIRC that was around the same time I volunteered to be part of a campus wide partnership with the local power company and I stood at a desk in the cafeteria handing out free CFLs bulbs.

The tl;dr is that companies will invest in expensive, less useful, signage, if it is perceived as being cooler.

Heck it isn't like menus carved/painted on wood have particularly good contrast ratios, but they still pop up now and then.

> they moved over to having a slide show on the screens that alternated between glamour shots of the food, and the menu. Now you could only see the actual menu for a fraction of the time, and despite being a speed reader, I'd often have to wait for the menu to come back around multiple times before I could read it all and decide what I wanted to eat that day.

I've seen this problem elsewhere. I don't get why you wouldn't display the menu on some of the screens and the photos on other screens.

They eventually got it sorted out, but for awhile it was.... less than stellar.

The local McD's drive thru has a giant LED screen where you can see your order and total cost. Very nice for confirming they understood what you ordered after:

Me: 3 Big Macs and 2 large Fries

McD: What?

Me: 3 Big Macs and 2 large Fries

McD: 4 Quarterpounders?

Me: T-h-r-e-e B-i-g M-a-c-s

McD: 3 Quarterpounders?

Me: Yes, and fries

I, as an equipment designer, would select an e-ink color display for my main feedback if:

- it was battery powered and needed a display with infrequent updates but super low power

- the display was otherwise a large part of the power (i.e. otherwise it was a LCD display)

- the color was useful in indicating an error or clarifying the menu items

If it did those things it would be worth upwards of $10 a unit to me if the resolution was over 720p for sure, and likely even for lower resolutions if it worked reliably with a slow microcontroller.

Signage. Advertisements, restaurant menu displays, etc.

New artistic styles often come from the limitations of their mediums. I expect the limitations of color e-ink to be no different.

I don't really see that in this case though.

The whole point I'm making is that no advertiser or restaurant is going to use color eInk because the contrast and saturation are so terrible.

This isn't like working around the limitations of a medium to develop pixel art, or black-and-white drawings, etc.

Color e-ink is just a worse medium in every way. It's worse contrast at black-and-white (B&W e-ink is far better), and it's terrible contrast and saturation at color.

I don't see it working for signs, ads, or menus at all.

Color e-ink feels like a cool prototype, a proof-of-concept, but that basically demonstrates its limitations don't make it commercially viable for any general purpose.

LCD billboards absolutely destroy my night vision. An illuminated color eink display probably would not.

Wouldn't it be technically possible to reduce the backlight for LCD displays at night? Seeing that it itsn't happening I have little hope that e-ink displays wouldn't be illuminated to the maximum as well ("out ads should be as bright and vibrant as possible!")

You can turn off the backlight for an LCD and rely on it being reflective, but the contrast is very poor since at least half the light is blocked.

In this application I see the use of e-ink as being:

- Maybe more readable if you're really fussy.

- Lowers overall power use.

The prior is super weak, LCDs do fine as long as they're not in direct sun.

The second is a good reason, but not a very compelling one in terms of economics yet.

The place these make sense is battery powered devices. If it's plugged in it is a gimmick or someone really dedicated to energy efficiency.

> Is there any practical use for color ePaper yet though?

CI and monitoring dashboards. These tend to have large relatively static areas for long periods. Every regular LCD I've seen gets horrific burn-in after a month or three and then burns a lot of wasted electricity for bonus points.

Ebooks with illustrations/graphs? Text books and graphic novels come to mind.

But that's my point -- the contrast for regular black and white text is so much worse with color eInk than it is for regular black-and-white eInk.

It seems like a terrible tradeoff to make, for colors that are still terrible.

Reading a graphic novel on a color e-ink reader will be so washed out... if you really want the color, it seems like you still have to just read it on an iPad etc.

Most of my medical books would be better with a color E-ink. In fact, I do not even have medical books on my current E-book reader.

At 31.2" though?

For some specialized uses, sure: think about researchers wanting to look at illuminated manuscripts, especially wanting to see marginalia and the like. A large, low-eyestrain way of seeing high-quality scans would be very handy.

I have Moss Roberts' translation of the Romance of the Three Kingdoms scanned to PDF. ( https://www.amazon.com/dp/0520224787/ )

The product page doesn't advertise it, but the books are huge. I can't actually read my PDFs because my kindle display is much smaller than that.

And yet the market for a reader with a bigger screen seems to be negligible. :(

There’s a lot of potential but pretty much all use cases are limited each in their own way by the current specification shortcomings.

Eg for the case you mention, the display ppi is simply nowhere near good enough for minute study of details.

That's, what, about 4-up letter pages? Yeah, I can see that being useful.

Can't get to the page; I assume the price is ridiculous though.

$2,300.00

My favorite use-case is a laptop that I can use to write/study/code in bright sunlight.

Or a phone. Do either of these exist yet as single display devices? I've only seen half measures with a regular LCD plus an e-ink add on that was very much a gimmick.

I would be so thrilled for an e-ink phone to get rid of my current one with. I don't play movies, the refresh rate doesn't need to be great, it does need to be color, and if the battery lasts a week again... well worth it.

Hisense has been offering eink phones for the past two years. The latest iteration is the A7 CC 5G with a 6.7" 300 ppi color e-ink display

Oh, that's exciting! I was last looking hard in 2018 but I'm still surprised I didn't notice.

Alas, I've got the whole "phone needs to be small enough to use one handed" due to disability stuff so https://www.gsmchoice.com/en/catalogue/hisense/a5c/ is their smaller one and it's a bit big but close...

Might be a wait until there's enough market for a niche of both not huge and also e-ink. There was a bar e-ink phone though! I'm surprised they can't just put a more complex OS on it given the resolution...

https://www.gsmchoice.com/en/catalogue/mudita/pure/

> Is there any practical use for color ePaper yet though?

> It's certainly not ready for advertising -- instead of a vibrant color image, it looks like something printed on newspaper and left to fade in the sun for 5 years.

This is still a big improvement over black and white if you're displaying, say, a math textbook.

did you look at the link OP shared?

Me personally: manga, retro magazines, papers with colored charts etc. I am still looking for the day when we can read magazines, manga from the past in full vibrant color e-ink platform.

edit: speaking of which I am looking to purchase high quality retro gaming magazines (PC, Playstation 1 in particular). anybody wants to get in touch please reply.

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