# Tenet Folio #Tenet #onyx-boox #plugable #dc-1 ## Background This idea began in August of 2023. At the time my preferred e-reader was a Kobo Sage. Unfortunately, the one I had was showing some odd and disruptive behavior. I set out to find a new e-ink tablet primarily for reading. I hadn't used the notetaking features on the Sage that much, but I was still intrigued by the possibility. Was there any device on the market that could compete with the reMarkable 2 while staying smaller than 8 inches diagonal? Specifically, here is what I wanted from a device: - Must read ebooks really well. This should include the Kobo and Libby apps, but I also want to be able to load my own pdfs and epubs onto the device. - Should let me annotate (highlight a passage and add my own note). Doing so with a stylus is nice but not necessary. - Could it let me draw on blank canvas? - Could it let me type documents with a keyboard? - Could it let me program in a shell session? My research led me to the Onyx Boox Nova Air2. It has notetaking, a custom app for reading, and it's compatible with the Google Play Store! The handwriting on the Nova Air2 sadly does not measure up to reMarkable's standard. But the fact that this tablet runs Android (11) means it can do way more than reading books and taking handwritten notes. I started using the tablet for typing notes (in Obsidian). I bought a folding bluetooth keyboard (I actually bought several, but quickly settled on one I liked best). This setup became my preferred travel computer due to its portability, but it still required a table or desk to use well. ## Folio While the tablet and its keyboard are portable, they're also a little bit unwieldy: they don't snap to each other for carrying, and they are also disconnected while deployed (which makes lap-based computing precarious). I would like to make something that does for the Nova Air2 what the [Type Folio](https://remarkable.com/store/remarkable-2/type-folio) does for the reMarkable: a case attached to the device with built-in keyboard. I looked around a little for generic "tablet case with keyboard" products and I tried a couple of options, but they were clunky. In order to be generic, they relied on elastic straps to hold the tablet, and because they were "one-size-fits-most" they tended to be too large for the Nova Air2. ## DC-1 The Nova Air 2 is great, and very portable, but then I backed the DC-1 hoping it would be able to replace the reMarkable _and_ the Nova. Turns out it can! Mostly... The one thing I use the Nova for over the DC-1 is portability. The Nova is much smaller and lighter, making it easier for one-handed reading, or reading while moving. I haven't tried sketching on DC-1 enough to know that it's better or worse than the reMarkable (software-wise), but the DC-1 is Android 13, so there must be an app out there that fits the bill. Hardware-wise, the sketching seems just fine! Compared to the Nova, DC-1 has more real estate, a more responsive screen, and a newer operating system. Compared to reMarkable, it's not a walled garden and it has a backlight. So I'm going to continue this eternal project by making the type folio for DC-1. It's bigger, which loosens some of the constraints. It has pogo pins, which might be neat to connect with (maybe I can get schematics?) ### Keyboard I'm inspired by two projects: a [portable M1 Mac Mini with iPad Mini for a display](https://www.core77.com/projects/112686/) and the [Crabapplepad](https://kumekay.com/crabapplepad/). some early decisions: - based on the geometry of the folio, I don't know exactly how tall the keyboard can be, but I'll aim for 4 rows (eesh) and up to 12 columns. I've used 40% keyboards before, and I can get used to it as long as the legends are clear. - I could use Choc switches and keycaps, because I already have them and they're through-hole and I know how to build with them. - or I could use some Cherry Ultra Low-Profile switches I had shipped from Germany for this project. They might even be quieter. The downside there is I then have to make my own caps. - whether I use a pogo-pin connection, usb-c cable, or wireless, I have a nice!nano for the microcontroller Fancy bits: - I wonder if OLED screens communicate over I2C (nice!view [seems to use SPI](https://nicekeyboards.com/docs/nice-view/getting-started)). Yes, I have one that is I2C! [0.9" 128x32 OLED](https://www.adafruit.com/product/3527). - the [pimoroni trackball](https://shop.pimoroni.com/products/trackball-breakout?variant=27672765038675) is I2C! #### Firmware - Cannibalized [Multisteno firmware](https://github.com/nkotech/Multisteno-Firmware) and get steno working on android with [Dotterel](https://github.com/nimble0/dotterel)? - embedded steno firmware: [Javelin](https://lim.au/#/software)? ### PCB #### 2023-08-21 I've started with the keyboard PCB. I'm planning to use one of my freebie Adafruit "Kee Boar Driver KB2040" MCUs, based on the RP2040 chip. I've made a draft in KiCad, and there are a few things I want to check before I send it off to the manufacturer: 1. put my name/date/design revision on it. For historical reasons. 2. double-check the ground pad under the MCU. Not sure I did it right. 3. Put a known drill hole pattern in it, for mounting to the switch plate. 4. a reset button on the front face? 5. encoders? 6. I should put the PCB edge cuts on a grid, along with the drill holes. and probably the key footprints too. It would be really nice if I could make dimensional drawings in KiCad, but I can survive with a grid. I had to redo the physical drawing a few times, because I noticed it didn't have the right shape of hotswap on it (which reminds me: I probably need to buy Choc hotswaps for this). I did the initial layout using a different Kailh footprint, and it struck me that even though I tried to follow the hardware drawing I have, I'm not 100% positive they match. I guess I can always cut a new plate if the first one doesn't fit. I should 3D-print a plate before I commit the drawing to brass! ### Folding Mechanism I want a folio that can support five modes: 1. closed, to protect its contents (including the stylus: on the inside) 2. lid open partway, so I can read while blocking the light from hitting someone next to me 3. lid folded back, for one-handed reading 4. (optional) lid folded back and tablet propped up by a kickstand 5. lid folded back, tablet propped up by a kickstand, keyboard ready for use My current plan is to make this happen in two pieces: one is a sleep cover for just the tablet. It will keep the stylus safe, and the front cover will be foldable like the "origami" case for the Amazon Kindle (the one that looks a bit like the Jedi Knight: Jedi Academy logo...). This sleep cover will snap to the keyboard piece. For the keyboard part, it needs to keep the keyboard safe while stowed, and allow for a solid typing surface when deployed. It will probably need to unfold or expand a bit to allow the tablet sleep cover to kickstand properly on it. And unfolding the keyboard should include gears and some soft detents. If I end up allowing for solar charging, I'll need to put the [[Universal-LIIon-Charger|circuitry]] somewhere. If that ends up making the keyboard part too bulky, I might have to make a separate box just for that. ## Appendix: Comparison Research ### Off the shelf portable "writerdecks" - Clockwork Pi's [DevTerm](https://www.clockworkpi.com/home-devterm) - [reMarkable 2](https://remarkable.com/) with [Type Folio](https://remarkable.com/store/remarkable-2/type-folio) - freewrite [Traveler](https://getfreewrite.com/products/freewrite-traveler) and [Smart Typewriter](https://getfreewrite.com/products/freewrite-smart-typewriter-3rd-gen) ### Tablets When I did the initial research for a new e-reader in 2023 I didn't keep extensive notes about which models I compared. I think I looked at the [Open Book](https://www.oddlyspecificobjects.com/projects/openbook/) and [PineNote](https://pine64.org/devices/pinenote/). I also looked into the manufacturers Modos, Onyx Boox, Dasung, and Kobo. I probably didn't look at Hisense, Pocketbook, or Supernote, but I should keep those in mind for the future. I should only give up Nova if I find another device with _all_ the same features _plus_ better writing experience. That means - read books (kobo, libby, calibre) - Obsidian (with typing) - Sketch + take notes - has a light - markup documents - if Android, at least 11 ### Keyboards - "Fyton" was nominally for the Samsung Galaxy Z Fold4. The smaller key grid was hard to get used to, but the overall size of this keyboard was an okay match for the tablet. Flimsy kickstand. - "Werleo" was nominally for the Galaxy Tab A7 Lite. It has a trackpad, but this sometimes crashes the Obsidian app on the tablet? I've updated the tablet's firmware since then, so maybe they fixed something. But also the trackpad is more sensitive than I want it to be, given I'm typing over it on a cramped keyboard. (Goodwilled) - Samsers is a split, angled keyboard that folds up _very_ thin. I wish I could remap the left spacebar. It also had a small key grid, and was hard to get used to. (Given to a friend) - Plugable also folds (not unlike the old Palm Pilot keyboard), but it's bigger in all dimensions than the Samsers. This is both pro and con: It's big and chunky, but its keys are full-size! Its size also presumably means a longer battery life, though I didn't really test the battery life of any of the keyboards here. ### Keyboard Switches Cherry ULP keycap/PCB sources: - https://github.com/pashutk/Cherry_MX_ULP?tab=readme-ov-file#keycaps - https://github.com/jonboh/ulp-dactyl?tab=readme-ov-file - https://gitlab.cairn-devices.eu/cairntech/cairn-mesa-key/-/tree/main/Mechanics/CAD/IGES%20files?ref_type=heads - https://shop.tai-hao.com/categories/low-profile - https://mechanicalkeyboards.com/products/tai-hao-purple-tht-18-key-abs-low-profile Crabapplepad sourced [Kailh PG1425X](https://www.kailhswitch.com/mechanical-keyboard-switches/low-profile-key-switches/low-profile-switch-for-notebook.html)