A demonstration of how to use the SparkFun Pro Micro (or similar) to implement a USB keypad for a workstation, using a cheap 4x4 switch matrix. This is the first step towards implementing a custom mechanical keyboard from first principles.
Keyboard.* and HID.* are taken from the Arduino libraries, for ease of building with a Makefile. If you're using the Arduino IDE, just include keytest.cpp in a sketch -- the other files are not needed.
For more details, see