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Ask HN: Cheap, hackable e-reader?
161 points by 0942v8653 on March 13, 2017 | hide | past | favorite | 57 comments
I would like to buy a cheap e-reader where I can replace the software with my own (or at least be able to write my own software that I can launch and stay in, with minimal UI chrome around it). Preferably about $50 or under. I would like to have a touch screen or to be able to use most of the buttons.

What are some good options for this?

If you just want to modify the existing OS and write apps for it the look at the kindle hacking community on the mobileread forums. The best devices are probably up to and including 5th generation kindles since I believe they are the latest to still have working soft-jailbreaks (but that could have changed since last I checked). I believe all kindle models are trivially rootable if you are willing to buy a 1.8v usb to serial adapter, open the kindle up and solder on three wires. If you want a 100% FOSS distro on your device and you're not afraid of soldering, cross-compiling and super-pre-alpha code then read on.

I've been working on a linux distro for i.MX based e-paper readers (kindle, kobo, etc.) for a while and just had two other hackers join me on the project. Currently we are furthest along with the Kindle 4th generation non-touch with a slightly modified super minimal Debian booting and basic graphics support (Xorg works but no window manager and no screen auto-update yet. e-ink is weird). I believe we've managed to strip out all binary blobs so it's really all open source now. This system is still using an ancient kernel (a slight variation on the one used by the stock OS). We just got the latest stable kernel booting a few days ago but only barely (not even mmc support yet). There's just three of us for now, and we hang out in #fread.ink on freenode and our code is up on https://github.com/fread-ink

You should look at the repo https://github.com/fread-ink/fread-vagrant to get started.

All e-ink Kindles prior to firmware 5.8.8 can be jailbroken without hardware modifications.


The Kindle hacking community believed they had a permanent solution prior to the release of the latest firmware version; unfortunately, Amazon seems to have finally found a way around it.

I don't think anyone with experience hacking kindles believed it was a permanent solution. Unfortunately, most of the technical expertise in that area is fleeting.

I'd recommend an older Kindle if you want to get root easier. 5th generation Paperwhite and older models should be cheap and have various exploits.

Probably would recommend a Kobo or something else though. Kindles are awesome pieces of hardware but they do try to keep them secure. Not the best choice for an open platform.

You are amazing :)

Kobos are quite hackable [1], to the extent that their Linux operating system is on a removable internal SD card, and you can run Debian on them [2].

[1] https://wiki.mobileread.com/wiki/Kobo_Touch_Hacking

[2] https://wiki.mobileread.com/wiki/Debian_Linux_on_a_Kobo

Kobos require nothing more than a 2 line shell script on an SD card to get telnet, after which, they publish their modified Qt sources, so you can even rebuild the UI framework without much effort, although I don't know much about keeping their proprietary display and touch driver blobs in place.

Back in time they had some kind of third party development support, so you could plug addons into the existing UI. AFAIK the framework hasn't changed much to prevent that kind of dev, and there example addons built around it

But in terms of a random stable embedded environment that is quite transparent, with an awesome out of box hardware/software experience, Kobo are not to be beaten

> they publish their modified Qt sources, so you can even rebuild the UI framework without much effort

Really? AFAIK, only parts of the distro are liberated, here:


Most notably, the user interface itself ("Nickel") is completely missing from there: this makes it really hard to develop extensions for it. Some people have gone through great lengths to try and improve the firmware image, see for example this guy who went as far as writing his own QT plugin for the UI, basically bruteforcing his way through undocumented APIs and missing source code:


He gave up in 2011.

I did my own share of fooling around with the Kobo. It's true that it's very easy to hack: just drop a `KoboRoot.tgz` tarball in the `.kobo` directory, and you basically overwrite any part of the filesystem, which gives you a lot of freedom. I wrote a tool to sync my Kobo with Wallabag here called Wallabako:


But there's no APK, far from it: the Kobo suite is developped in typical proprietary fashion of keeping the secret sauce to themselves, not a collaborative way. And even though they are less hostile than Amazon in trying to keep people out, nothing says they will keep on being nice like this.

What we really need is a liberated hardware e-reader. There are some examples elsewhere in this thread that are interesting...

I second this. It is very easy to run custom software on Kobos (at least the Kobo Aura HD I have). Executables built with the cross-compile tool chain shipped with Debian work flawlessly on the device. The screen can be easily used with the provided /dev/fb0. The reader also acts as a virtual USB network device, so you don't have to rely on a clumsy WiFi connection. Another plus (at least for older models) is that the devices are quite easy to open and that the internal storage is just a normal removable micro SD card. So you can't really brick your device.

All in all it took me a few hours to write a simple application which renders the current time and date with a TTF font to the display.

Kobos are extremely easy to modify and completely not "protected". I highly recommend them. Many of them have touch screens and wifi too if that's of any benefit to you.

There's a pretty decent dev community that has Qt fully working too which could offer you a good starting point. There are already full UI replacements going on in the community, like KoboStartMenu and KoReader.

Completely agree that Kobos are better than Kindles for hacking purposes. Generally not as easy to find cheap used though.

Depends on your country, in Canada at least they're stocked by our largest chain bookstore. They're quite readily available online just about anywhere though.

That's because they fall apart in a few months (at least the two I got did).

I'm pretty sure koReader is available for kindle as well. I have it on my paperwhite

The catch with the Kindle and why I would suggest the Kobo over it is that Amazon has tried and in the most recent firmwares has succeeded at blocking modifications.

The Kobo has no such protections, it's fully your own device and you can mod it as you see fit. Additionally, the whole OS is on an internal SD card and if you fuck everything up you can crack it open and reimage your SD card. Perfect tool for modders.

The bq cervantes[1] is open source[2] but isn't so cheap.

[1]: https://www.bq.com/es/cervantes-3-bq [2]: https://github.com/bq/cervantes

I'm planning on picking one up soon (or, hopefully, a Cervantes 4 if it comes out...). I'm (fortunately in a position where I can be) willing to pay the extra to support F/OSS out of the box :).

Cool! I did not know this existed!

Just wrote this, let me know if I can be of any help!


That looks really neat. If you ever decide to make a 2nd version, making the bezel about 500% smaller would look a lot more attractive.

Also, the C code you listed was very cute. :3

i like the bezel

I don't mind it myself, but I kind of can't unsee the fact that it looks like it's dwarfing the tiny screen. Most picture frames have a 1 inch or so bezel, and I guess if I was trying to emulate a physical device I'd want to copy it as accurately as possible to maximize the surprise factor.

Great post, I love the water scene idea!

Thanks for the comments and feedback!

The Nook Simple Touch can be rooted. I found it to be a little bit unstable, but YMMV.


Simple Touch readers should be dirt-cheap.

I rooted mine back in 2014 and found it useful and quite stable. I haven't investigated the scene since so it may have progressed significantly.

You can configure it such that the Nook would boot and appear as normal, but holding down a key took you to the android launcher, and you would give up the use of two (redundant) buttons of your choice to control android-specific actions like <back>, etc.

This system was limited -- at the time -- to an older version of Android with limited app support, but if your purpose is to create your own apps this shouldn't pose any problem.

Anyone know anything about this: https://getremarkable.com

It's been advertised pretty heavily, and on the face of it looks like everything I want in an e-ink sketchbook/reader.

I have a suspicion that it will disappoint, however.

Doesn't even seem to be available yet (website still offering preorder && no Amazon listing as far as I checked).

I'm currently looking at a simple 7th-gen Kindle. ( https://www.amazon.com/Amazon-Kindle-6-Inch-Previous-Generat... ), for $35. I've done some research, and it seems that it is possible to jailbreak it, but I would like to be sure I can really write software for it before I buy.

It's possible to jailbreak any Kindle as you can preform a downgrade to a vulnerable firmware version.

I am extremely interested to hear how I could do this on a 7th gen/2014 model Kindle Touch.

PocketBook, I guess. I never tried programming it myself, only installed some plugins, but it's basically a Linux underneath, so, I guess, a lot can be done. And unlike all these shady Kindle/Kobo/Nook/whatever they don't have any notion of DRM, they are just a device.

My own is quite old and the screen is not top-notch, I don't know how advanced and expensive they come right now. But give it a look.

I like this idea, and I'd like to take the question one step further: are there any affordable development platforms which can work with eink screens? I've read that the screens themselves are pricey due to EInk's de-facto monopoly on supply, and difficult to work with due to the need for things like manual temperature compensation just to drive the display.

But surely there must be breakout boards by now, right? Or a raspberry module that's larger than 3"? Can you effectively source raw screens through the usual hobby suppliers like digikey, mouser, jameco?

You can, I've used Pervasive Displays (I bought them from Digikey, they also have breakout boards): http://www.pervasivedisplays.com/

But yeah they are kind of complicated to drive. I've only used the small ones, but you do the refresh pattern manually - you also need to compensate for the temperature, and the pixel layout is a bit funky. Luckily there's already software for this at repaper.org, so you don't have to worry about it. The complicated logic being in software opens the doors for more complex refresh logic as well. Just keep in mind if you do this you can burn in the display, so buy a couple if you plan to experiment :)

Huh. I thought controllers were insanely complicated or used proprietary technology. This is interesting to hear!

What exactly is temperature compensation? I'm aware that it's a thing, but I haven't yet figured out what it is. Do you have to alter the drive voltage or current or something?

Also, I'm not currently aware of any open e-ink driver designs. A few people might be interested in the one you built, regardless of how simple it is. Of course standard disclaimers would apply.

It's way simpler than that, you just write the displayed image more times based on temperature. If you don't do it your display will just have less contrast in the code.

The chip-on-glass has tons of registers to set drive voltages and the like, but the datasheet just gives you values to write to all of them.

What do you mean by e-ink driver? If you mean the software, check out the Arduino and Raspberry Pi librares on the repaper site. If you mean the hardware, just follow the schematics in the datasheet and repaper.org.

> It's way simpler than that, you just write the displayed image more times based on temperature.

Oh! Nice.

> If you don't do it your display will just have less contrast in the code.

That's a really great failure mode for debugging/development :) you can just use a single repaint count until you have temperature sensing wired up.

> The chip-on-glass has tons of registers to set drive voltages and the like, but the datasheet just gives you values to write to all of them.

Oh okay - so there _is_ a controller. (I didn't know; totally ignorant about the subject.)

> What do you mean by e-ink driver?

Ah; I've just done some poking around, and I just realized I misunderstood things a bit when I last did some research (way too quickly, apparently) - I saw http://www.pervasivedisplays.com/images/Kits/Extension%20boa... and thought I'd need to cram everything on that board onto the final design. I didn't realize the displays were more or less self-contained (with a builtin/COG controller) and could be driven directly like LCDs or VFDs etc and that that board was the "kitchen sink" test/dev breakout kit.

You do need part of that - a lot of it is capacitors wired directly to the ribbon cable, for the COG's charge pump. There's also a temperature sensing chip and a couple of external mosfets, one of which is to fix a bug on older COGs. On my own layout I was able to shrink it quite a bit by using 0603 parts. Still expect to burn 300mm^2 on the passives. https://0x0.st/tqo.png

Ah, I see. Thanks.

Inkbook looks pretty hackable: https://inkbook.eu/shop/inkbook-classic-2/

Has anyone hacked the boogie board? It is extremely cheap.

Edit: Googling this seems to be a good resource [1] and it looks like it is using an msp430 so should be hackable. But I don't actually know much about this stuff, so if someone does hack it I'd love to know how

[1] http://forums.hackaday.com/viewtopic.php?f=2&t=846

> Has anyone hacked the boogie board? It is extremely cheap.

It's not a software controllable display. It uses a film concept similar to an etch-a-sketch and in the recording model, it uses a touchscreen to read the pen action, but there is no pixels/no matrix and no display that can be drawn to by software.

Information in that thread and elsewhere suggests that the MSP430 doesn't have the ability to display information on the screen. Drawing on the screen is a purely mechanical effect, and the microcontroller is only used to clear the screen.

More information on the technology:


What's particularly interesting about these displays is that it does seem possible to read the image from the LCD (particularly the Jot 8.5 and the Sync; the others don't explicitly say). I'm trying to figure out whether the display device itself integrates memory cells or whether there's a tablet sensor overlaid on top. The website doesn't seem to want to explain much.

I'm under the impression the sync can be used to read the image, since it does have a save feature. I'm wondering if the reverse can be done too? Could you make the display show an image that was previously saved?

I'm curious why you think the jot 8.5 can save. I do know the earlier models were using an msp430, which others are suggesting cannot save the image. I actually have one of these Jots, but I don't know anything about hardware hacking so I'm not going to tear it apart (unless people just want pictures of the guts and possibly what chips are in there)

Other commentators have mentioned that the display in other devices cannot be read, and from the website it's clear to see the company focuses solely on ChLCD (cholesteric LCD) technology.

This would depend on whether the "read from LCD" capability is an intrinsic part of the ChLCD itself or a manufacture-time option, or if it's a separate capacitative or optical-barrier touch layer.

I just did a bit of digging, and I found some info on repairing the Boogie Board Rip on iFixit: https://www.ifixit.com/Guide/Boogie+Board+Rip+Internal+Anten... - this shows what looks like some kind of touch layer, along with a bunch of extra electronics.

There's also a smartphone showing a 1:1 copy of what's on the Jot on the fourth image as you scroll down at https://myboogieboard.com/ewriters/jot-8.5.

The jot uses a phone app and the phone's camera to get the picture. So I don't think there is any way to read the screen on that device.

However the sync has a button which you can save the screen image and later upload it to your computer. What I'm wondering is on this device if you could do the reverse. I know being able to record the screen's state doesn't mean you can reproduce it. Just wondering if you can in this case.

I know nothing about ChLCD and that type of stuff. So this isn't really clear to me.

Oooooh. Thanks for that information about the Jot. That's remarkably good advertising showing the smartphone on the webpage like that, I have to admit.

Regarding the Sync, I suspect it contains the same electronics as the Rip in order to do the sync thing, and a touch panel.

Based on the other comments I've read in this thread that explain how "writing" on screen (and "ink" showing up) is entirely mechanically driven, ie, the pressure on the surface of the display displaces the crystals and makes whatever you draw stay on the screen. Applying a voltage for a short moment somehow causes the crystals to reset.

I'm not sure why the display itself wasn't made writable. It's entirely possible Kent Displays simply couldn't find a viable way to market a (MCU-)writable version of this technology, and so they went in this direction instead; it's also possible that ChLCD (developed up to the point Kent have it at) doesn't have the capability to be addressed reliably. I have no idea.

I based my hunches above about how the Boogie Board resets on something I saw on TV a while ago, which I just determined is classified variously as "switchable privacy glass", "electrified privacy glass" or "intelligent glass". I learned (from the house-construction TV show) that it's essentially a single, gigantic (!) LCD "pixel", and I saw (in one of the construction stages) how simply plugging it into the wall and turning the wall switch on was what made it go from opaque to transparent. Obviously it's a fair jump from this to the Boogie Board reset mechanism, but it seems reasonable that some of the same ideas are used in both.

Then how does the sync save the display? There have been a few upgrades since the hack I found.

I've been doing a lot of research on this recently including contacting Chinese wholesellers to see what individual parts would cost.

Essentially all I'm after is a Linux (not android) based 7-12" eink tablet with touch screen, a decent resolution / PPI for the size and at least say 2-4GB of ram at a minimum although if it was cheap enough I'd drop as far as 1GB if I really had to.

I have a Dasung E-Ink monitor and it's dreadful, lots of ghosting, very slow refresh, have to have some 'interesting' software running to make it work, hard to work with multi-desktops etc.... and very, VERY expensive: https://www.indiegogo.com/projects/paperlike-world-s-first-e... otherwise I'd attach that to a Pi or Cubox and live without the touch screen.

What sorts of price ranges did the wholesalers provide, and for what? (I don't need exact values, just a rough idea.)

Thanks for the info about the Dasung. A video showing the screen at its absolute worst might be very useful - but to be fair, showing what things the screen does do well would be very interesting to know as well.

For anything even slightly useful with a half decent display I was still looking at USD $200+ per unit and many wouldn't supply just one.

Oh wow :/ that's quite a shame.

On the other hand, this means that the Chinese "photocopying industry" doesn't realize people want (decent!) e-ink readers. Window of opportunity, anybody?

I have a generation 2 kindle and I would trade it for nothing, I miss having the backlight so I actually need to have a light in the room but other than that the amount of "hacking" I did on it is extremely impressive - oh and if you ever read this, thank you twobob for all your hard work on the kindle

If you're willing to take it a step further and have some experience with hardware (or you are willing to learn), you can even buy a bare e-ink screen and interface with it. For example, the ED060SC4 is cheap. The datasheet is not very helpful, but if you look carefully, you can find some drivers on github, or more generic tutorials on e-ink drivers.

http://essentialscrap.com/eink/ is probably one of the most helpful resources out there if you want to do this.

Oh man someone could easily buy these at scale, 3d print some casing, and sell them as e-ink raspberry pi screens. Good demand and no reasonably priced supply.

Buying e-ink screens for e-reader might be a problem. During the last project with e-ink screens, we had an explicit clause with supplier implying that these screens will not be used for e-readers. That was 3 years ago though, things might have changed since.

This is a great tutorial. Unfortunately the Espressif SDK it uses is out of date, and I was unable to get the source working with the current SDK.

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