Oddly Specific Objects has launched a crowdfunding campaign for the Open Book Touch, an ESP32-S3-based e-reader with a 4.26-inch e-paper display with 480 x 800 resolution and a capacitive touch screen.
The open-source hardware device comes with 16 MB flash, 8MB PSRAM, a frontlight with warm and cool LEDs, a microSD card for storage, and an 800 mAh user-replaceable LiPo battery with everything housed in a 3D printed enclosure.
Open Book Touch specifications:
- SoC – Espressif Systems ESP32-S3 dual-core MCU with Wi-Fi and Bluetooth LE connectivity
- Memory – 8 MB octal SPI PSRAM
- Storage
- 16 MB quad SPI flash
- MicroSD card slot
- Display
- 4.26-inch, 480 × 800 e-paper; 1-bit and 2-bit grayscale with dithering
- Capacitive touchscreen based on FT6336 low-power controller
- Frontlight – five warm + five cool LEDs, independently dimmable
- USB – USB Type-C for power/charging and programming
- Misc – 3D-printed plastic enclosure; snap-fit, with 3D-printable CAD for custom shells; note: injection molding possible as a stretch goal
- Power Supply
- 5V via USB-C port
- 800 mAh user-replaceable LiPo with integrated charging and monitoring
- Dimensions – 78 × 120 × 10 mm
- Weight – 85 grams
While the Open Book Touch can be used as an e-paper dev board programmable with Arduino or CircuitPython, most of the firmware/software work has been done to create a nice e-book reader.
The default firmware has been written with the ESP-IDF framework to optimize performance and power consumption. It relies on Focus, a lightweight, platform-agnostic C++ UI framework for resource-constrained embedded systems, inspired by NeXTSTEP’s AppKit and Apple’s UIKit, which comes with view controllers, a touch-and-gesture system, a full set of on-screen widgets, and even an on-screen keyboard.
The firmware supports EPUB and plain text, with hyphenation, justification, and inline images, offers multilanguage support with around 70,000-glyph Unifont and a UI localized in seven languages, including right-to-left ones, fast refresh performance between page loads, and a DRM-free experience allowing you to transfer your books over WiFi through a built-in web interface.
Open Book Touch is open hardware with MIT-licensed firmware, schematics, board files, enclosure CAD, and source code to be released before shipping, although the source code for the Focus application framework has already been released.
There are plenty of e-book readers with touchscreen support, such as the Kindle or Kobo Clara BW, and some other readers do not require DRM, have a replaceable battery, and partial open-source support, but none of them have all these features in one device as the Open Book Touch offers. The main downsides I see are the smaller display and the limited number of supported book formats (for now). Another open-source hardware ESP32-S3 e-book reader not in the list above is the Diptyx E-Reader, which has a different dual-screen design and relies on physical buttons instead of a touchscreen for user interaction.
The Open Book Touch e-book reader is now available on Crowd Supply with a LiPo battery and a microSD card for $149. There’s also a $249 Open Book Touch “Author’s Edition” with a premium enclosure, but details are sparse for now. Shipping is free to the US and $12 to the rest of the world. You’ll need to be patient as rewards are only scheduled to ship by April 2027.
Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.
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More than double the price of the Xteink X4 (not to mention X3), bulky enclosure, and very little gain. More critically its lacking the mature ecosystem (ie a multitude of flashable firmwares). I think it’ll be DOA.
Weirdly Xteink hasn’t been covered on CNXsoft
A nice overview/review:
https://blog.omgmog.net/post/xteink-x4-e-ink-reader/
Discussion on HN:
https://news.ycombinator.com/item?id=48662381
Thé M5Stack Paper S3 has all of these features except the removable battery at one third the price.
But for some reason they discontinued it (the black and white version).
I am a BOOX Leaf user. Very much frustrated with BOOX. They do not release the GPL code. I quite like a cheap e-reader with too long battery life. But I have several criticisms on this thing:
Regarding the last point, I do want a decent e-reader like Leaf I have but with Linux support. To make us closer to the goal, I have extensively contributed to postmarketOS wiki: https://wiki.postmarketos.org/wiki/Category:Ebook_reader
As I have written in the respective wiki pages, both PocketBook and Kobo openly permit running custom OS/firmware on their ebook readers if you can go outside warranty.
ESP-based devices are more likely to be able to have a longer battery life. Anything which runs Linux will have a pretty power-hungry SoC that is going to drain battery a lot quicker. So it’s probably a matter of choice between power and battery life.
I followed your link and checked all the PocketBook and Kobo device pages and they tell me:
That doesn’t quite leave many options, much less any recent ones.
The only device that seems to easily fit the bill is the PineNote, but it’s on the larger (and more expensive) side.
Well why create a hardware from scratch. You could write custom software for those Kobo devices. Those Cortex-A7 run at 1Ghz. Downclock them to the clock ESP32-S3 has and you probably will get roughly the same power consumption.
Sure, many Kobo devices are not supported by pmOS directly. But you can install KOReader on them. So Kobo Clara BW does run custom code unless KOReader docs are incorrect.
There also used to be QuillOS but now they have moved to PineNote.
Only e-reader to be Ahmish DemoScene scroller of your books in SX-520 fonts, be mistaken for 4 e-paper price tags in a front-lit trenchcoat, and maybe ship with an optical overlay that promises to just ‘dump tokens’ into your eyes.
What do they mean by “require drm”?
I’ve got a Clara and can read non-DRM docs on it.
Other than raw hackability I don’t see any upsides to this.
Lemme clarify something about the earlier comments I had. If we see this device as a start to liberate the world of e-readers, it could be a very good effort. If it goes well, I would appreciate it very much. But as a device to use as a real e-reader daily, nope it isn’t.
If the efforts of Open Touch people lead us into an open e-reader ecosystem, it makes all sense that the first open hardware e-reader doesn’t catch many eyes. Perfect is achieved step by step. It doesn’t come for granted for free. However, going for ESP32-S3 still would be a valid criticism.