gEDA is a set of open source software by Ales Hvezda, whose main task is creation of projects of electronic devices (CAD). This package has the tools to trace pc boards (PCB), preparate for production, change the electrical circuits and not only. It should be noted that the collection of projects was designed for UNIX-compatible platforms, but some programs have been ported under Windows.
Due to the fact that the utility uses the binaries and opens nmap on the command line, you can create java. This software is ideal for the design of devices of medium difficulty.