Open Source EDA Links

Open Source tools work best when there is a community-wide effort to provide the best software to the greatest number of people. Most open-source developers believe that all open source code is good and that more open source code is better. After all, when source code is open and available under a standard license agreement like GPL, any good algorithm or method is free to be used, copied, modified, and spread around the world to the benefit of everyone.

For example, the vectored text rendering in xcircuit was borrowed and used in gEDA's "gschem" tool. I borrowed code from the SourceForge project "acroformtool" to add PostScript-compatible flate compression/expansion to graphic images in xcircuit. For that matter, by compiling and linking to open-source libraries for Tcl/Tk, I have added scripting capabilities to all of my EDA tools. The Tcl/Tk development community then continues to add capabilities to my software without my having to lift a finger. Isn't Open Source great?

So, I heartily recommend to every end-user to find the tools work best for you. And when you find something broken or missing, remember that it is your duty to request a fix or a new feature, or modify the code yourself and submit a patch. And when Cadence (not to pick on them, particularly; there are many others) is forced to reduce their prices to $100 a site license, we will have done our job.

Below is a list of Open Source EDA tools that I know about, or that have been reported to me. If you know of others, please let me know and I can add them to the list.

This is a web-based design and simulation environment mainly aimed at circuit board-level projects. The business model is similar to that of the company I am working for, efabless, with a crowdsourcing model of user-generated designs for purchase but a free software frontend. They have direct connections to Shenzhen PCB manufacturers but will allow you to download your own gerber files.

Schematic entry and printed circuit board generation tool written by Sergei Iliev. Completely open source, and hosted on SourceForge.
Links for sites with electronics projects, tutorials, etc.
This is the platform I've been helping to develop for several years now. The web-based part of it has a circuit IP catalog and marketplace. Originally geared toward ASIC analog circuit and chip design, it has expanded to incorporate digital circuits (with an emphasis on mixed-signal microprocessor SoCs), programmable devices (especially programmable analog), and board-level projects. My tools (qflow, qrouter, magic, netgen, etc.) are hosted on the design platform called "Open Galaxy", are configured for working with real foundry processes, and are free to use once you register with the site.

Maker Pro
This site looks rather like a Hackster spinoff, but it has a lot of educational/tutorial content that sets it apart.

The premier site for projects, very heavily Arduino and Raspberry Pi oriented. Do a search on "RISC-V" to find a handful of stuff done by me and acquaintances of mine.

Homeadvisor Residential Electrical Circuit Help
This is a little off-topic because most of the content of is directed toward electronics, but given that a lot of Maker types (I'm one of them!) are increasingly incorporating circuit projects into their "smart homes", it's worth knowing the electrical basics.

The links below have been around for a while. Some of them are still good, and I need to sort them out sometime. . .
EEWeb Electronics Forum
Excellent forum for all sorts of Electronics questions and answers.
A loosely-knit organization of a number of open source tools, including ng-spice and icarus verilog, among others.
The SourceForge project page for ng-spice
A port of ng-spice as an extension of Tcl/Tk. This is a bit cumbersome, as one of the main development directions of ng-spice was to add interpreter-like capabilities (an unfortunate choice, if you ask me---there are already plenty of interpreters out there not to spend the time to write a new one). But I once looked at the idea of replacing the ng-spice interpreter functions with Tcl/Tk, and it is not a trivial task. So redundancy exists. tclspice uses the Tcl/Tk "BLT" package to add plotting capabilites with continuous updates.
chipmunk tools
John Lazzaro's interactive analog and digital circuit simulators. I have some updates but have not managed successful ports to recent Linux/GCC versions. This could still be a very nice program if lifted out of the ancient HP Chipmunk graphics system that was its original environment. Maybe I'll work on that sometime.
Kicad home page
Kicad users Yahoo group
Kicad devel Yahoo group
Kicad Wiki
Links sent to me by Remy, a devoted Kicad user. Kicad is an open-source GPL schematic entry and PCB board layout tool (includes a Gerber viewer and 3-D component-level viewer).