A library to interface Arduino with XKeys USB keyboards

Thomas Strausbaugh contacted me a while back with a project involving XKeys – a series of HID keyboards with extended functionality. Tom also offered to lend me XK-16 Stick; after receiving it I made a small addition to the USB Host Shield library and soon after Tom e-mailed me back asking to test his code. The picture on the left shows one of the example sketches, a “blinky” of sorts, where all backlights are sequentially turned on and off.

Xkeys can be controlled by sending proprietary (but well documented) output report which doesn’t follow standard HID report format. By sending this report it is possible to turn LED integrated into each key on or off, change light intensity, as well as switch the keyboard on the fly between mouse, joystick, and keyboard emulation modes. Larger keyboards have some additional features. In addition to that, products are very maker-friendly; for example, a manual for XK-16 Stick contains this:

Customization
The electronic design of the X-keys Stick is such that the stick may be cut off to any length after the second key. P.I. Engineering will perform this service in our lab for a fee including testing to maintain the warranty, or you may contact us for specific instructions if you wish to do it yourself.

The big disadvantage of Xkeys is price. However, if you want you project to look professional but don’t have much time to refine it, a good looking user interface can be produced very quickly with Xkeys.

Tom’s library implements programmer’s interface to extended keyboard features (sans cutting). Easy to use functions are provided enabling direct access to programmable features of each key or LED. Thank you very much, Tom!