Overview of KiCAD – free electronics design program.

KiCAD is a program for electronics design. It includes a schematic editor, PCB editor, Gerber files viewer and some utilities. It also has a 3D modelling capability, but the render quality is lower than that of competitors. Nevertheless, it is enough for visual design checks and enclosure allocation. There are Windows and Linux versions of the program. Also, a Mac OS version exists but is not stable yet.

The program’s main benefits are its price (free!) and functionality, which is not limited compared to free versions of Eagle or DipTrace. KiCAD can work with up to 16-layer PCB and has no limits on its size. There are quite a lot of element and footprint libraries for KiCAD. Also, it has well-designed editors to make your own quickly. The central part of the KiCAD concept is separate libraries for elements and footprints. On one side, it requires an additional step in design to allocate a footprint to a component, but on the other hand, it adds a lot of flexibility. For instance, we have one schematic symbol for a resistor, and we linked a 0805 SMD footprint. But during the PCB design, we changed our mind and decided to use a 0603 SMD instead. In this case, we don’t need to go back and change a schematic. We just changed the link. Such a concept allows only one footprint of a type (i.e., 0805 or SOT-23) and links it to a component, avoiding keeping and creating copies for each. At first glance, I thought such a concept was not too convenient, but I changed my opinion after completing the entire project cycle from schematic design to Gerber files – it is good.

The user interface can be considered as a disadvantage of the program. It is not intuitive enough and requires a manual to do some stuff. But I believe that Eagle has the same issue. This problem appears at the start and almost disappears after one or two projects are completed in KiCAD. Good manuals for it can be found here: http://www.kicad-pcb.org/display/KICAD/KiCad+Documentation. Reading them significantly reduces the time to learn the program. Also, they have a lot of valuable tips.

Generally, the development cycle in KiCAD starts with creating a schematic in the “Eeschema” program. Then footprints are allocated in the “Cvpcb” program. The next step is to design PCB and prepare Gerber files for production in the “PCBNew” program. It is possible to step back on each stage, make changes and pass them forward. Because several programs are involved in the design, understanding their links is essential for practical work.

Also, a netlist can be saved in “Spice” and used for a circuit simulation in any program that supports this popular format. It is straightforward to create Bills of Materials for its order. It has an extensive list of options and formats for the output file. “Bitmap2Component” is included in the package, which allows creating logos on a silkscreen layer or touching buttons on copper layers. A handy “Pcb Calculator” is also included in the package.

Many components, footprints and 3D models library are located here: www.kicadlib.org. I use this great online utility to create multipin components for a schematic: http://kicad.rohrbacher.net/quicklib.php. It allows me to quickly create different components using pin names from data copied from a datasheet edited in Excel.

I considered the 3D PCB rendering function as a toy at first glance, but I changed my mind after I became familiar with it and tried to use it. It helped me to find a couple of mistakes in my design, so now I use it for each design that requires enclosure allocation or has tight component placement. KiCAD already has the most basic 3D models. A lot more can be downloaded from the library mentioned above. Also, most manufacturers have 3D models of their components on Internet sites. Unfortunately, they usually use “iges” or “step” formats that KiCAD does not recognise. It requires the “.wrl” format made by the “Wings3D” program. It is also a free program but doesn’t recognise “iges” and “step” formats either. By the way, making your 3D model of a component in this program is relatively easy, especially if you don’t need to detail it highly. I’ll show you how to do it quickly in one of my future posts. “Wings3D” can be downloaded here: www.wings3d.com. It is free and can be launched under Windows, Linux or Mac OS. The perfect manual for the program can be found here: www.vrspace.org/sdk/vrml/tools/wings3d/wings3d_manual1.6.1.pdf. I highly recommend becoming familiar with it and understanding its central principles before starting to use it. It will save a lot of time.

KiCAD is very well documented, so I don’t see any point in further describing its work. But the topic of 3D model preparation isn’t covered enough, so in the next post, I’ll show you how to prepare such models for it quickly.

I’ve decided to use this program as a main for my hobby projects.

All my posts about KiCAD that exist at the moment can be found here.

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