efbpad

A bluetooth keyboard terminal for a Kobo Clara BW.

See the TODO.md. Also see a related repo, kobo-emacs

This is completely untested works-for-me-ware. Although this doesn't touch any non-user directories, you could still brick your device if you don't know what you're doing so be careful.

Build and Install

• On the Kobo, install kfmon and nickelmenu if you haven't already.
• Run make to produce an update package KoboRoot.tgz. This requires a cross-compiling environment. NiLuJe's koxtoolchain kobo env is the path of least resistance.
• Merge the contents of the package with the kobo's /mnt/onboard (n.b. there are files starting with .). Alternatively, put the tarball in /mnt/onboard/.kobo/KoboRoot.tgz and reboot. Either will create an efbpad entry in kfmon, nickelmenu and koreader's Tools menu.

Prebuilt

Instead of compiling everything you can try things out with a (maybe out-of-date) pre-built package here.

Usage

• Before starting, pair your bluetooth keyboard through the Kobo UI.
• While your bluetooth keyboard is set to attempt to pair with the Kobo, run efbpad from any of the above launchers. At startup efbpad (efbpad.sh) will:
  • source /mnt/onboard/.efbpad_profile if it exists.
  • Turn on the Kobo's bluetooth.
  • Try and open the event device at /dev/input/event3 to use as the keyboard. If no device is there, it'll wait 5 seconds after bluetooth up for the keyboard to appear.
• efbpad shuts down and cleans up if it never finds a keyboard, if the keyboard disconnects or if the shell terminates. (The last case requires that you type an extra char on the keyboard to exit).

NiLuJe has helpfully provided a package containing busybox, tmux and ssh here. As described in the link, it creates several tunnels via udev rule (then /usr/local/stuff/bin/stuff-daemons.sh) which should be disabled with

touch /mnt/onboard/niluje/usbnet/etc/NO_TELNET
touch /mnt/onboard/niluje/usbnet/etc/NO_SSH

For uninstallation, efbpad creates these files and directories:

• /mnt/onboard/.adds/efbpad
• /mnt/onboard/fonts/tf
• /mnt/onboard/efbpad.png
• /mnt/onboard/.adds/kfmon/config/efbpad.ini
• /mnt/onboard/.adds/koreader/plugins/efbpad.koplugin

Fonts

fbpad will look for fonts at /mnt/onboard/fonts/tf/{regular,bold,italic}.tf. If .efbpad_profile sets the EFBPAD_FONT env var then /mnt/onboard/fonts/tf/${EFBPAD_FONT}_{regular,bold,italic}.tf will be copied to that location for use.

The included fonts were produced on the kobo as so, running from a folder containing DejaVu ttfs:

mkfn -h 44 -w 24 DejaVuSansMono.ttf:42 > /mnt/onboard/fonts/tf/large_regular.tf
mkfn -h 44 -w 24 DejaVuSansMono-Bold.ttf:42 > /mnt/onboard/fonts/tf/large_bold.tf
mkfn -h 44 -w 24 DejaVuSansMono-Oblique.ttf:42 > /mnt/onboard/fonts/tf/large_italic.tf
mkfn -h 36 -w 18 DejaVuSansMono.ttf:31 > /mnt/onboard/fonts/tf/small_regular.tf
mkfn -h 36 -w 18 DejaVuSansMono-Bold.ttf:31 > /mnt/onboard/fonts/tf/small_bold.tf
mkfn -h 36 -w 18 DejaVuSansMono-Oblique.ttf:31 > /mnt/onboard/fonts/tf/small_italic.tf

Project Structure

Broadly, we string together 4 components. An effort has been made to keep them as decoupled as possible.

• FBInk: A library for eink screen drawing by NiLuJe.
• fbpad: A framebuffer terminal emulator by aligrudi. We use a very lightly patched version of fbpad: it occasionally makes a call to FBInk to refresh the screen.
  • Here we follow the example of a similar project, fbpad-eink, which took a more integrated approach to refreshes and had a different keyboard system.
• kbreader: Under proper conditions keyboards appear in linux as event devices. kbreader acts as the interpreter to translate keystrokes coming out of an event device into strings printed to stdout. This is a standalone utility. When you start fbpad it waits for chars from stdin. We get fbpad to listen to the keyboard by piping kbreader into it as so: kbreader /dev/input/event3 | fbpad the_shell.
  • kbreader is spiritually identical to the onscreen keyboard in a similar project inkvt, except our keyboard reader is decoupled from the rest of the software, our event device is not a touchscreen, and we use fbpad instead of a bespoke VT.
• efbpad.sh: Script that does efbpad startup & shutdown.