Do you have an old Macintosh computer laying around? Why not blow off the dust and follow these simple steps to do an upgrade to OS X? You don’t even have to spend hundreds of hours creating the source code for the custom microcontrollers that interface the system together since it is available for free on the site.

“This is a Macintosh 512k which I upgraded to run OS X by replacing the innards with a modern Mac Mini and various supporting components, including a grayscale CRT monitor, an LS-120 floppy disk drive, and a microcontroller-based USB device that interfaces the Mini to the original keyboard and mouse. Why? Mainly because I wanted to experiment with creating a custom USB device. Also I guess I wanted to waste hundreds of dollars and countless hours building a semi-useless computer with a 9 inch black and white screen and no arrow keys.

The most interesting part of the project for me was the circuit that allows the old original keyboard and mouse to be used with the Mini. It is based on an Atmel AT90USB162 microcontroller, which is basically a standard AVR µC with a special coprocessor dedicated to USB signaling. It comes with a C library that makes it relatively easy to create USB devices like HID keyboards and mice, speakers, storage devices, etc.”