1. E-ink requires a number of external components, even with their "chip on glass". In particular, E-ink requires a high voltage to change and charge the ink. I've seen inductors on most of these reference designs (ie: suggesting a boost converters of some kind).
2. E-Ink is very slow especially at this price range. Static images are fine, but don't expect animations.
3. E-ink protocols take a "temperature". In my cases, I've just been hard coding it to 25C / Room temperature, but this suggests that low-temperatures or high-temperatures may change the behavior of the screen.
4. E-ink is very "bursty" with power, using more power than LCD when changing images, but then zero power for most of its life. Be sure to think carefully about the current associated with this burst, especially if you're using small CR2032 coin cells (which have ~10 to ~100 ohms of internal resistance). A ~100mA draw on the charge inductor isn't out of the question (at 10-ohms, that's a voltage drop of 1V, which probably browns-out the RP2040). A slow-start circuit could solve this but you'd need to consider the longer charge times. Another method is to have 2x CR2032 cells in parallel, which lowers IR (parallel resistors lower resitance). I'd be most interested in studying the power-network of this design, I bet there's some interesting things going on here.
5. Most E-ink screens seem to be some kind of SPI protocol (4 wire). This is very similar to mini-LCD screens.
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LCD screens use more power, but get you color, more resolution, animation and seem to be cheaper still. Furthermore, LCD requires fewer external components (maybe a charge-pump set of capacitors, but some LCD screens don't even need that). Note that color/resolution/animation all costs processor power / storage / RAM, so be careful what you wish for.
LCD might be more suitable for beginners. But e-ink is very cool and awesome.
This is using an IT8951 EPD controller I wrote a little Rust driver for, which indeed talks SPI, although its SPI frontend is really a quirky/leaky abstraction over an I80 interface so you have to e.g. do chip select using I80 semantics and send preambles and such. Still, pretty breezy overall.
Can confirm the power draw is of course "bursty" during the update. Also, yes, e-ink refresh times get slower in colder temps. e-ink refresh also works poorly in direct sunlight. The displays can also "dry out" from it and it can cause artifacts. But the envelope for normal operation is overall fairly good, certainly for home/indoor use.
There's a fair amount of manufacturing tolerance and during testing manufacturers will usually record preferred drive voltages for the individual unit, etc. It's quite important to configure software to make use this information for optimal performance.
I'm hoping it will run for about a year without recharging from that little 1100 mAh LiPo pouch at one update a day (the newspaper is rendered on a common home server RasPi using LuaLaTeX+Ghostscript and then retrieved over Wifi), having taken self-discharge into account.
For more du-jour hype points I'm considering using OpenAI on the backend to summarize articles down to size to fit the layout! Or make it do style transfer to "1870 newspaper".
You can find this unit and other IT8951-based driver boards for it on a few different places/in different catalogs but Waveshare's easy and the price seems OK.
The ED133UT2 is a Carta 1200 display. The latest Carta gen is the 1250, but AIUI it's only relevant for color displays with the change being a thinner film that allow plastic color filters to be closer to the ink to improve contrast. I think the current greyscale 13.3" offered by E Ink's direct shop for $449 sans driver is still a 1200 - at least many vendors list VB3300-NCB as just an alternate name for the ED133UT2. The Carta range of displays are well-known from Amazon's Kindle and many other reader products, so my newspaper is basically a big honking DIY Kindle.
They also offer a 10.3" panel with even higher resolution for half the price of the 13.3" that's supported by the same controller and should be fantastic for all sorts of home dashboards.
I saw something like this a couple of years ago and wanted to do it myself. However the cost was relatively unattainable at the time, I'm glad to see it is getting more affordable!
This seems to be pretty common with E Ink displays unfortunately (you hear the same about many commercial ebook readers). At least the larger ones are more or less all from the same manufacturer (E Ink). I don't know if there is binning going on and Amazon gets better batches than Waveshare does ...
Direct sunlight can also be a big problem for this display tech, so I'm intentionally hanging it on a wall facing away from the most intense daytime sunlight I get.
While cobbling together my project I was really tempted to go custom PCB with the ESP and the ITE controller on one board. Looks like this eschews the seperate controller entirely and instead uses ESP32 PSRAM for the framebuffer and has the driving waveforms embedded in the MCU firmware etc. Very neat, also one further level of "go deeper", would love to try one!
Thanks for sharing the price. The build looks really good, but $400 is a bit steep for anybody on a budget. I think a good quality (high coverage and pixel density) LCD with auto-brightness would be economically competitive, though of course not really the same.
Look into memory reflective lcd's, doesn't look quite like e-ink (and for quite a few of them you have to resort to dithering instead of proper greyscale), but they're considerably cheaper and offer the same power benefits.
Additional benefit is that they're quick to refresh, if you have an application that requires it. I have a calculator built with it, works perfectly.
I love it! On a somewhat related note, I've been working on a tiny Forth interpreter lately, and I think the e-ink device it could be an interesting choice to explore and test it on as a dedicated computational environment. Inkplate looks very appealing: https://soldered.com/product/inkplate-6plus-e-paper-display-...
You might want to check out Kagi to summarize articles: https://labs.kagi.com/ai/sum. It does the heavy lifting of producing nice outputs for you.
Not yet, sorry! It's still very fresh; I'll be releasing on GitHub pretty soon after cleaning it up a little and writing some documentation. When getting around to it I'll remember your comment and drop you a line.
Wow, haha, that's extensive. However, I'd urge you to release first and write docs later (or even release first and make it work later). I'd get a lot more value from code with no docs than no code at all!
E-ink should be, but it never seems to get there. Too low-contrast and/or too expensive. It's been a Real Soon Now technology for about two decades.
There was another persistent display technology - chomeric displays. They came from a company called Chomerics, which was acquired by Parker Hannefin, which dropped the product line. Almost everything about those has disappeared from the Web, except that the former factory is now a Superfund site.[1]
I’m cautiously optimistic, because two decades is the lifespan of a patent. E Ink the company has been a terrible steward of the technology. May they lose their state-sponsored monopoly and fade into irrelevance in peace.
I talked to someone building related tech in the industry and E-Ink the company has a stranglehold on suppliers and leverages that to force compliance despite the patent nearing expiration (blocking anyone else from getting access to those suppliers).
The patent has allowed them to become entrenched and all current suppliers to depend on them. This will be hard to correct even with patent expiration.
I don't remember the specific details (unfortunately) and it's second hand info, but I was disappointed to hear it from someone more involved than I.
E-Ink is apparently engaged in anti-competitive practices. Why should it matter that the market in question is small?
Lots of companies do this. Amazon demands exclusivity for certain book sales, and they have contracts with sellers that make it hard for other marketplaces to undercut them. Qualcomm is famous for abusive practices. The list goes on.
In general, IMO companies should be able to compete by offering a superior product and/or a superior price point and/or a superior experience. They should not be able to compete by getting in each others’ way.
You are of course correct. The far bigger core problem is that our government is generally captured and does not serve one of its core purposes, enforcing competition, i.e. preventing manipulation of markets. A way that a legitimate and constitutional government would do such a thing, would be, e.g., require competitive practices, e.g., e-ink screens must be sold to anyone so wants to buy them at fair price, to put in end products … if the company e-ink wishes to engage in interstate commerce, which is supposed to be regulated by Congress.
However, because Congress and the whole government is inherently illegitimate as is easily objectively measured by its constant, frequent, and persistent failure to abide by the constitution; things like industry capture of government and fraudulent regulatory bodies, is now the norm.
People don't realize that e-ink and related technologies simply _don't sell_, and rather make up crazy conspiracy theories about eInk for some reason sabotaging their own product.
Consumers don't accept the disadvantages of eInk, such as the low refresh rate, the apparent low contrast, and the extremely poor color reproduction. At the same time, the advantages are rather minuscule; in fact, people have a hard time distinguishing eInk from reflective LCD. They think reflective display == eInk, while in truth many devices popularly seen as "eInk" are actually reflective LCDs (e.g. the Pebble and Garmin smartwatches).
Most companies that have made non-LCD based products are simply out-sold by LCD products and go bankrupt. I could probably name half-a-dozen non-LCD reflective technologies which are dead today without even checking Wikipedia, like Gyricon, Mirasol, the stuff the OLPC used, Flepia, etc. All of them dead or niche.
You just can't point fingers at eInk since some of these technologies faded even before eInk even existed, and some of them are owned by companies which are at least ten times larger than eInk (Qualcomm, Fujitsu, etc.). These theories claiming that eInk is the large neighborhood bully just don't many any sense whatsoever. Qualcomm, for example, _is_ a well-known bully; unlikely to be scared of eInk's portfolio. But Qualcomm released exactly 1 product with Mirasol - which completely flopped in the market - and then gave up on it.
Even price displays are usually LCDs, with only a minority being eInk, but as you can see here, casual hackers have a hard time distinguishing between them.
The small displays they put on smartcards (showing a 2FA or the like) are also LCDs, and even with a practically minuscule battery they last for half a decade, and that's refreshing itself once per hour... I couldn't think of a better usecase for eInk, and yet it fails to beat a much cheaper plain old LCD, save for perhaps if you wear polarizing glasses...
> make up crazy conspiracy theories about eInk for some reason sabotaging their own product.
Why do people make up crazy stories about banks conspiring with the bond-rating agencies to sell bogus financial products to their clients, oltimately crashing the entire market and driving themselves into bancrupsy. I mean, no rational person would do such a thing!
This is an LCD screen with active-power measured in micro-amps. This means that memory-lcd is more power-efficient than e-ink even if it updates once every 5 minutes. (though the less you update, the better e-ink gets).
If I’m not mistaken yes the power does go. I have a smartwatch with a 30day+ battery life (Amazfit Bip) which also uses I believe the same type of display.
It’s ~somewhat similar to a calculator 8 segment display in operation - low power, low resolution/pixel density, can be inverted etc. Or maybe old gameboys perhaps?
Maybe for you. But the first Kindle came out in 2007, and Amazon has sold tens of millions of them. The latest, the Kindle Scribe, even allows users to write in books with a pen.
I have an e-ink tablet (Boox Tab X), which is like a Kindle Scribe except it's also a (more or less) full featured Android tablet.
I have a very nice setup with Zotero, where I can sync papers I want to read to the tablet (running Zoo for Zotero), read and mark them up, and then sync the marked up version back to my computer.
I'm very interested in those Boox tablets.
Is there a way to have them display a static image (a custom website or Android app) when they are in standby? Or do they force-switch to some screen saver mode, like many e-readers do?
I've been using it since my previous job bought me a Sony PRS-505 (a co-worker got an Amazon Kindle).
Works well, w/ great battery life, and it really has come into its own w/ the new Kindle Scribe --- a large screen e-ink device which works as an e-reader and has useful note-taking and annotation capabilities (looking forward to seeing what competitors do w/ it --- probably would have bought an Onyx Tab Ultra if the Scribe hadn't been available).
I'd really like to see an affordable display suited to a Raspberry Pi, ideally w/ touch.
> E-ink should be, but it never seems to get there. T
Every price tag at my local grocery store is eInk. Like there must be thousands. I'm guessing there are updated by wifi. I mean that is pretty damn good use and the refresh rate means you saw real energy over LCD.
Funny you should bring this up, I just thought about it today what a terrible development those electronic price tags are from a consumer perspective. Because of course the next step is constantly changing the prices based on customer data telling them how to extract the maximum amount of cash from shoppers. Which is what I noticed at stores where they do have them, in extreme cases they change the prices of some products multiple times a day.
My neighbor is quoted substantially lower prices on the same car sharing app as me, for the exact same cars. I don't know if it's the sole reason but she has a really old smartphone. Actually surprised me she can even still run the app on it.
The phone is maybe possibly part of it but most of actuarial calculations for car rentals are more based around age/zip code/sex and whatever driving history they can find on you than anything else.
Meanwhile in real world, the local grocery store can't even notice when products on their shelves have already expired. Sometimes by quite a long while. Not going to hold my breath for that one.
I use Onyx A4 reader and it has completely replaced paper for me. Making notes directly to PDFs while I read them is fantastic. And it saves my eyes. The only drawback is the price (around $1k). I am not watching videos on it though.
One very widespread use of two-color (red and black) e-ink screens is grocery store price labels. They're everywhere in Canada, and they work great. Even the fine-print (price per 100g) is clearly readable.
I don't know if they have batteries and wi-fi, or if they're updated manually with NFC, but either way they can't be too expensive if there are 5000+ in every store. They're a bit smaller than the badges these guys made, but they might be a lot cheaper and easier to work with.
Ive seen similar (maybe the same) red black eink screens at best buy in the usa for pricing labels as well over the last year, so they're not exclusive to north of the border. Far fewer labels than a grocery store though.
> I don't know if they have batteries and wi-fi, or if they're updated manually with NFC
Yes, yes, yes, and other methods. These are called "Electronic Shelf Labels", and there's a whole slew of competitors.
WiFi is very high power, so its "pull only twice a day" kinda setup. You have a radio that only turns on twice a day to contact the server. Zigbee is also a solution, though that requires a Zigbee router (coordinator? I forget the terminology). Much less power on Zigbee, but if you're deploying hundreds/thousands of these ESLs, I think the benefits of Zigbee low power outweigh the penalties.
NFC exists but I don't think I've ever seen them in person. Probably too much effort since it'd require a human walking around the store?
I've even seen ESLs that work off of infrared. You're supposed to install IR LEDs all around the store, and they can it all shelf-labels to update. IR receivers are the lowest power, so this is the only way you can feasibly "push" data to a shelf label. (Wifi and Zigbee are "pull only").
So some computer blasts the IR signal around the whole store, which is enough information to transmit to change all the prices apparently. Like a giant broadcast remote control.
There was some information only recently on HN about reversing those Electron Shelf Labels [0] that was quite interesting, but your comment makes me wonder if you could eavesdrop these wifi price updates in such stores. Also, searching for that term on HN gives some other fun projects.
I can confirm that they start to act weird around high temperatures. Just exposing it to the sun for a few minutes on a hot day can make dots not transition correctly
> small CR2032 coin cells (which have ~10 to ~100 ohms of internal resistance). A ~100mA draw on the charge inductor isn't out of the question (at 10-ohms, that's a voltage drop of 1V, which probably browns-out the RP2040).
n=1, but I'm using a single CR2032 with a Badger 2040 (same as OP) and a DS3231 in parallel and it works just fine down to ~2.8 volts.
By the way, for the e-ink project I just linked in the other comment I ended up discovering the RV-3028-C7 RTC module. Idle power draw 45 nA at 3.3V instead of 110 µA for the DS3231 for similar functionality and ±1 ppm accuracy with an internally sealed oscillator. Awesome for battery-powered stuff and cheaper at low qty on Digikey.
I hope more of those little DIY/maker breakout boards adopt it. Pimoroni sells one. The one in my project is a free sample dev board that Micro Crystal sent me on request - which I guess is working out for them considering I just shared their product with you all.
Recently, I have come across some interesting developments in the e-ink space. Although I haven't had the opportunity to test DASUNG monitors myself, but I read positive reviews. It is impressive, these monitors have extremely fast refresh rate. Yes, they are pricy. I am intrigued if something has changed technologically?
Your comment made me curious, but after looking at a teardown blog the 13" Dasung Paperlike uses the same ED133UT2 panel by E Ink as in my DIY newspaper project, which is a panel originally released about 2016/2017.
That said getting good partial refresh performance out of a panel like this requires a good controller and good code (after having written a driver for one such controller recently), and developers and product integrators have gotten more refined at this. Refresh speed and display quality are still a trade-off here though, expressed as different waveforms when driving the same display.
First ; Gosh I wish I had the knowledge you have on electric transfrerence/resistance==ohms/volts
But given that coin discs input/output are heat-dependent based on your comment, and no knowledge, would it not be sound to place CR coin batts in a baffle of graphene-aero-gel which could be just mm thicc and shield them from said temp inflections? This would greatly increases life, and can be moulded and produced en-mass with little effort and minimal cost (especially if you encase batteries used in space flight etc - and one may use the non-conductive format to use aerogells as an extremely light and thin insulating layer for many a thing.
Imagine the ability to 'spray' an AeroGel sealant onto a component which is heat sensitive to its accuracy...
Hopefully that answers any questions you have. You might need to research some other bits of knowledge to build up your base EE skillset, but once you're able to read those documents + understand them, I think you'll be in a good spot.
> Another method is to have 2x CR2032 cells in parallel, which lowers IR (parallel resistors lower resitance).
Don't do this. It will work for a short time, but this basically just drains one of the CR2032 cells dead.
The issue is that lithium cells have very little discharge slope, so by the time the two voltages equalize, one of the cells is about to die.
This is in contrast to alkaline batteries which have quite a bit of discharge slope, so the two batteries can equalize voltage with most of their battery life still remaining.
For very small stuff, OLED displays are another possible alternative. Great contrast, and there's no backlight so you don't spend power on the "off" pixels.
You could start with SSD1306 (monochrome, 3.3V) and SSD1331 (16-bit color, boosted voltage required). They speak I2C and SPI, and have decent software support.
The cheap and cheerful ones are <=1" diagonally though, so you need to step off the happy path to find badge-sized ones.
Could you recommend any good similar size as well as functionality LCD for my personal project? Charging is not an issue (short term use), minimal equipment and clarity at screen are key requirements.
Second the power draw on refresh - that surprised me for the projects I was using it with. Especially if you’re planning on any kind of animation or dynamic display, it can eat your power budget a whole lot faster than you were expecting.
1. E-ink requires a number of external components, even with their "chip on glass". In particular, E-ink requires a high voltage to change and charge the ink. I've seen inductors on most of these reference designs (ie: suggesting a boost converters of some kind).
2. E-Ink is very slow especially at this price range. Static images are fine, but don't expect animations.
3. E-ink protocols take a "temperature". In my cases, I've just been hard coding it to 25C / Room temperature, but this suggests that low-temperatures or high-temperatures may change the behavior of the screen.
4. E-ink is very "bursty" with power, using more power than LCD when changing images, but then zero power for most of its life. Be sure to think carefully about the current associated with this burst, especially if you're using small CR2032 coin cells (which have ~10 to ~100 ohms of internal resistance). A ~100mA draw on the charge inductor isn't out of the question (at 10-ohms, that's a voltage drop of 1V, which probably browns-out the RP2040). A slow-start circuit could solve this but you'd need to consider the longer charge times. Another method is to have 2x CR2032 cells in parallel, which lowers IR (parallel resistors lower resitance). I'd be most interested in studying the power-network of this design, I bet there's some interesting things going on here.
5. Most E-ink screens seem to be some kind of SPI protocol (4 wire). This is very similar to mini-LCD screens.
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LCD screens use more power, but get you color, more resolution, animation and seem to be cheaper still. Furthermore, LCD requires fewer external components (maybe a charge-pump set of capacitors, but some LCD screens don't even need that). Note that color/resolution/animation all costs processor power / storage / RAM, so be careful what you wish for.
LCD might be more suitable for beginners. But e-ink is very cool and awesome.
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