USB to USB keyboard protocol converter
======================================
Hardware requirement
--------------------
Arduino Leonardo
http://arduino.cc/en/Main/ArduinoBoardLeonardo
Circuit@Home USB Host Shield 2.0
http://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-2-0-for-arduino
Build firmware
--------------
$ git clone git://github.com/tmk/tmk_keyboard.git
$ cd tmk_keyboard
$ git submodule init
$ git submodule update
$ cd converter/usb_usb
$ make
Program converter. Push reset button on Leonardo before run this command. Serial port name(COM17) depends your system. On Linux I got /dev/ttyACM0.
$ DEV=COM17 make program
or
$ avrdude -patmega32u4 -cavr109 -b57600 -Uflash:w:usb_usb.hex -PCOM17
Limitation
----------
Only supports 'HID Boot protocol'.
Not support keyboard LED yet.
Update
------
2014/12/11 Added Hub support(confirmed with HHKB pro2)
Resource
--------
USB Host Sheild 2.0
https://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-2-0-for-arduino
https://www.circuitsathome.com/products-page/arduino-shields/usb-host-shield-for-arduino-pro-mini
USB Host Sheild 2.0 source
https://github.com/felis/USB_Host_Shield_2.0
Arduino USB Host Shield(with bootst converter)
http://arduino.cc/en/Main/ArduinoUSBHostShield
Arduino source
https://github.com/arduino/Arduino/hardware/arduino/{cores,variants}
Initial release of TMK USB-USB converter
https://geekhack.org/index.php?topic=33057.msg653549#msg653549
http://deskthority.net/workshop-f7/is-remapping-a-usb-keyboard-using-teensy-possible-t2841-30.html#p74854
Arduino-based hardware keyboard remapper - Colemak forum
http://forum.colemak.com/viewtopic.php?id=1561
Teensy + Host Shield
http://www.pjrc.com/teensy/td_libs_USBHostShield.html
a0d6bb1818