The Teensy is very similar to the Arduino, but one of the benefits is it lets you change how the device is presented to the OS. For example, you can make it present as a USB HID Gamepad/Joystick, keyboard, mouse, etc. instead of just a COM device. Here is how to configure a joystick with the Teensy: http://www.pjrc.com/teensy/td_joystick.html I have done this with another customer controller I was making for the Raspberry Pi and it worked perfectly, just didn't know how KSP would interact with a joystick, never tried it.