I wanted to add some features like vi cursor and mouse keys to my [HHKB][HHKB] but its controller is not programmable and firmware source code is not open, of course. This means customizing this keyboard needs to replace original controller with programmable one.
Set `MCU`, `BOOTLOADER_SIZE` and other build options in `Makefile` and `config.h`. If your target is **HHKB JP** you need to set `HHKB_JP` build option in `Makefile`.
Several version of keymap are available in advance but you are recommended to define your favorite layout yourself. Just `make` with `KEYMAP` option like:
You have some options for hardware. Development boards with USB AVR family(ATMega32U4, AT90USB1286) like Teensy will work while MegaAVR with [V-USB] library is also cheaper option for DIY.
Design files are available at [Keyboard Controller Board for HHKB(KiCad project)](https://github.com/tmk/HHKB_controller) and see [Controller Distribution thread](http://geekhack.org/index.php?topic=56494.0) if you get an assembled one.
###2. PJRC Teensy
See [this thread](http://geekhack.org/index.php?topic=57008.0).