Kicad:GPL PCB Suite

Kicad is an open source (GPL) software for the creation of electronic schematic diagrams and printed circuit board artwork.

Designed and written by Jean-Pierre Charras, a researcher at LIS (Laboratoire des Images et des Signaux) and a teacher in IUT de Saint Martin d'Hères.(France), in the field of electrical engineering and image processing.
Kicad is a set of four softwares and a project manager:

• Eeschema :Schematic entry.
• Pcbnew :Board editor.
• Gerbview :GERBER viewer (photoplotter documents).
• Cvpcb :footprint selector for components used in the circuit design.
• Kicad: project manager.

With the project manager, Kicad, you can choose or create a project and launch Eeschema, Pcbnew, etc. This electronic workbench is free of charges and is open source (GPL). It is useful for everybody working in electronic design (schematic diagrams and Printed Board up to 16 layers).

This software (using WXWIDGETS) is MULTI-PLATFORM. It is running under LINUX and Windows (XP or 2000), for which updates are regularly provided. Currently, the precompiled version of Linux has been tested using Mandrake 9.2 or 10.0 (works with 10.1).
Sometime the softwares are also been tested under other O.S., especially FreeBSD and Solaris.

(Source: http://www.lis.inpg.fr/realise_au_lis/kicad/)

EdSim51:The 8051 Simulator for Teachers and Students

Do you want to learn about microcontrollers and embedded systems? Are you studying the 8051 microcontroller? Do you want to test your code for communicating with peripherals without having to first build the hardware? Are you teaching an embedded systems course and would like your students to have access to a virtual 8051 training kit?

If the answer to any or all of the above is true, then you've come to the right place. The EdSim51 Simulator for the popular 8051 microcontroller is exactly the tool you need. And it's FREE!

A virtual 8051 is interfaced with virtual peripherals such as a keypad, motor, display, UART, etc. The student can write 8051 assembly code, step through the code and observe the effects each line has on the internal memory and the external peripherals.

The Virtual Peripherals:

• Analogue-to-Digital Converter (ADC)
• Comparator
• UART
• 4 Multiplexed 7-segment Displays
• 4 X 3 Keypad
• 8 LEDs
• DC Motor
• 8 Switches
• Digital-to-Analogue Converter (DAC) - displayed on oscilloscope

Why EdSim51's Simulator and not some of the many other simulators that are available?
Many of the simulators for the 8051 that you will find are industry-standard. They are used by professional 8051-based embedded udent can learn how to scan a keypad, multiplex 7-segment displays, control a motor asystems designers. While they show the state of the registers, memory and the port pins while code is being debugged, they do not have graphical representations of peripherals that can be used interactively to communicate with the 8051. EdSim51 have filled that need. The stnd count its revolutions, etc.

Download EdSim51 here.

(Source: http://www.edsim51.com)

Sonnet Lite

Sonnet Lite Version 11.53 is a free feature-limited version of Sonnet's professional Sonnet Suite, which provides EM analysis to hundreds of companies across the globe. Many major manufacturers of high-frequency components and boards depend on Sonnet to analyze their predominantly planar high-frequency designs from 1 MHz through several THz. You can download it right now - it's FREE!

Key Benefits of Sonnet Lite

• Most accurate, reliable planar EM software in the world
• Easy to learn with clear tutorials and online help
• Fast and efficient
• It's Free!

(Source: http://www.sonnetusa.com/products/lite/)

Scicos: Scilab's block diagram modeler/simulator

Scicos is a graphical dynamical system modeler and simulator toolbox included in the Scilab ® engineering and scientific computation software. With Scicos you can create block diagrams to model and simulate the dynamics of hybrid dynamical systems and compile your models into executable code. Scicos is used for signal processing, systems control, queuing systems, and to study physical and biological systems. New extensions allow generation of component based modeling of electrical and hydraulic circuits using the Modelica language.

With Scicos you can:

• Graphically model, compile, and simulate dynamical systems
• Combine continuous and discrete-time behaviors in the same model
  
• Select model elements from Palettes of standard blocks
• Program new blocks in C, Fortran, or Scilab Language
• Run simulations in batch mode from Scilab environment
• Generate C code from Scicos model using a Code Generator
• Run simulations in real time with and real devices using Scicos-HIL
• Generate hard real-time control executables with Scicos-RTAI and Scicos-FLEX
• Simulate digital communications systems with Scicos-ModNum
• Use implicit blocks developed in the Modelica language.
• Discover new Scicos capability using additional toolboxes.

Scilab

A Free Scientific Software Package

Scilab is a scientific software package for numerical computations providing a powerful open computing environment for engineering and scientific applications.

Scilab is an open source software. Since 1994 it has been distributed freely along with the source code via the Internet. It is currently used in educational and industrial environments around the world. Scilab is now the responsibility of the Scilab Consortium, launched in May 2003. There are currently 25 members in Scilab Consortium.

Scilab includes hundreds of mathematical functions with the possibility to add interactively programs from various languages (C, C++, Fortran…). It has sophisticated data structures (including lists, polynomials, rational functions, linear systems...), an interpreter and a high level programming language.

Scilab has been designed to be an open system where the user can define new data types and operations on these data types by using overloading.

A number of toolboxes are available with the system:

• 2-D and 3-D graphics, animation
• Linear algebra, sparse matrices
• Polynomials and rational functions
• Interpolation, approximation
• Simulation: ODE solver and DAE solver
• Scicos: a hybrid dynamic systems modeler and simulator
• Classic and robust control, LMI optimization
• Differentiable and non-differentiable optimization
• Signal processing
• Metanet: graphs and networks
• Parallel Scilab
• Statistics
• Interface with Computer Algebra: Maple package for Scilab code generation
• Interface with Fortran, Tcl/Tk, C, C++, Java, LabVIEW
• And a large number of contributions for various domains.

A large number of contributions can be downloaded from Scilab Web site. Scilab has been built using a number of external libraries.

Scilab works on most Unix systems (including GNU/Linux/Vista) and Windows (9X/2000/XP). It comes with source code, on-line help and English user manuals.

(Source: http://www.scilab.org)

NEC2C and XNEC2C

nec2c:
nec2c is a translation of the Numerical Electromagnetics Code (NEC2) from FORTRAN to C. Operationally nec2c differs from NEC2 by being a command line non-interactive program, taking as arguments the input file name and optionally the output file name. While translating NEC2 to C I also took the liberty of changing the output format somewhat, without realizing at the time that I was making it incompatible with visualizing software such as xnecview. Others, though, have taken nec2c and restored the output format while improving its functionality and speed, as well as building a C++ library based on nec2c.

Read more details on-line or download nec2c's manual.

Since version 0.6, nec2c incorporates a fix for a bug that was inherited from the original NEC2 FORTRAN code. This has been kindly fixed by G. Burke and you can read more details about it here.

Download source package of nec2c.

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xnec2c:
xnec2c is a GTK+ graphical interactive version of nec2c. It incorporates the nec2c core which it uses for reading input files and calculating output data, but it does not need and indeed does not produce an output file by default. Since xnec2c incorporates the nec2c core, it has access to all internal buffers, including structure data, frequency-related data (structure currents, input impedance, gain etc) and radiation pattern data (for the far field and near field). It therefore has the ability to graphically display user-requested data directly, as the frequency loop progresses or after input from the user. Graphs of frequency-related data and the current or charge distribution evolve as the frequency loop progresses, and radiation patterns (far and near field) are sequentially drawn for each frequency step. A new frequency can be entered by the user from spin buttons in the main or radiation pattern windows or by clicking on the graphs of frequency-related data. New output data are then computed and displayed in text and graphical form.

Read more details on-line or download xnec2c's manual.

Download source package of xnec2c.

Example Input Files: This directory has some example NEC2 input files that I used for testing xnec2c. They include some antenna designs of interest to radio amateurs as well as possibly to professional radio engineers (short verticals for low frequencies).

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These are screen shots of xnec2c displaying structure currents or charges, frequency-related data and radiation patterns.
Click on the thumbnails for the full-sized images.

Current distribution in the structure	Charge density in the structure	Frequency-related data: Gain, VSWR, Zi	Radiation pattern: transparent wire grid

gEDA Project

What is gEDA?

The gEDA project has produced and continues working on a full GPL'd suite of Electronic Design Automation tools. These tools are used for electrical circuit design, schematic capture, simulation, prototyping, and production. Currently, the gEDA project offers a mature suite of free software applications for electronics design, including schematic capture, attribute management, bill of materials (BOM) generation, netlisting into over 20 netlist formats, analog and digital simulation, and printed circuit board (PCB) layout.

The gEDA project was started because of the lack of free EDA tools for UNIX. The tools are being developed mainly on GNU/Linux machines, but considerable effort is being made to make sure that gEDA runs on other UNIX variants. For a complete list of freely available tools please be sure to visit Open Collector.

Tools that are part of gEDA/gaf (gschem and friends):

• gschem : Schematic Capture (Screenshots)
• gnetlist : Netlist Generator
• gattrib : Attribute Editor (screenshot)
• symbols : Symbol Library
• utils : Utilities
• gsymcheck : Symbol Checker

(Source: http://www.geda.seul.org)