Since some years different companies sell small little boxes, which can be connected to PC or notebook computers by USB or Ethernet and can than be used as a Digital Storage Oscilloscope (DSO). Although the principle design of such a device is no secret and different project proposals for the construction are available, no complete schematics can be found in Internet. My own (not fully finished) schematics and a short description are available here:
My principle goal is to build a few prototypes and to offer some minimal, open-sourced software under free GPL license.
My draft of a simple and cheap, but untested analog input stage for a DSO is available here:
I have written a plain command line driven footprint or "land pattern" generator for the PCB-program of the gEDA collection of free software tools for Electronic Design Automation (EDA). It is written in Ruby, see this page for more information:
The USB is the prefered method to connect various microcontroller-circuits with a modern PC.
I build an experimentation board for the 8-Bit microcontroller AT90USB1287 (AVR) of Atmel corporation and developed a free USB-firmware (GPL) for this controller. The operation of the firmware is demonstrated with a small application program, which uses the internal Analog-to-digital converter of the AT90USB chip to record an analogue electrical signal, and sends the measurement data over USB to a (Linux)-PC.
More information about the experimentation board (schematics, pcb layout and bill of materials) can be found here: A detailed description of the USB firmware is available here: Alternatively you may go directly into the source-text directory: