New adventures in PCB design - Embedded.com

New adventures in PCB design

This is the first in a series of blogs exploring open-source and free printed circuit design tools and online communities for developers who either do not have the experience or the bankroll to go to a professional tool.

After reading a few comments on Altium's new free CircuitMaker PCB design tool and community, I decided to take a closer look at the Fritzing tool and community web site, which several readers recommended to me. If you have some free or open-source tools that have impressed you, let me know and I will review them here.

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Altium's CircuitMaker
I have been familiarizing myself with Altium's new free PCB design tool and community and so far I like what I see. It encompasses much of what I like and need in such a community. In addition to dozens of online video tutorials it has several dozen detailed written presentations. During its first nine months or so of existence many designs and examples have been added that you can learn from, or modify to fit your needs.

It is also a social and comfortable site, which makes it easy to wander in and out of projects and discussion groups. The ambience is much like cafeterias at high tech companies I used to visit, where design teams would sit together for lunch, talking about their work or some general tech topic. If I wandered by and got interested in what they were talking about it was easy and comfortable to just take a seat and listen in.

But while the CircuitMaker site will be useful to fairly sophisticated open source hardware design DIYers, it seems a big jump for students and other beginners as well as design dilettantes like me who are still at the kicking-the-tires and the moving-the-pieces-around stage of such design efforts.

Also, even though the CircuitMaker site has a community willing to support fellow PCB designers in their efforts, it is almost too helpful, with constant comments from members when they see someone making a mistake. For me – and I think for many beginners and students – it is more useful initially to work in an environment where I am able to putter around making mistakes and learning from them without being distracted by well-meant comments. At the very beginning I like to just experiment, Tinker Toy constructor kit style, and see what works and what does not.

Fritzing and learning from mistakes
That’s why I was pleased to be introduced to the Fritzing open source tool and community web site. Although I am not abandoning Circuit Maker, the Fritzing site has a set of tools that are more helpful as I explore all the ins and outs of PCB design.

Created by a team of engineering students at the University of Applied Sciences of Potsdam in Germany, the Fritzing PCB design approach draws its inspiration from the Arduino breadboard-based paradigm that is popular among hardware do-it-yourselfers. But as Arduino users eventually discover, that platform’s breadboard approach is too fragile to be practical in any sort of commercial end product. If it is targeted at some sort of IoT application it is just too big.

That’s where the Fritzing tool comes in. It is designed for non-engineers or first semester engineering students who are just the first couple of steps beyond an Arduino or other bread-boarding prototype platform. Indeed, if a user of the Fritzing tool has created an Arduino design and wants his or her first Fritzing PCB to interface to it, the defaults are set to an “Arduino shield” to allow it to plug in to the Arduino platform.

Starting out on Fritz
Unlike professional PCB tools and free open source ones that start with a schematic diagram view, the starting point on a Fritzing design is the image of a blank Arduino-like breadboard. But it incorporates two additional views, one a schematic based on the electrical features that are created in the breadboard view and the other a PCB view with the look and feel of a professional tool, in this case the one from Eagle.

The Fritzing PCB design tool's default view is of a breadboard, similar to the look and  feel of a standard physical Arduino breadboard.

The Fritzing PCB design tool's default view is of a breadboard, similar to the look and feel of a standard physical Arduino breadboard.

Similar to CircuitMaker, the Fritzing site has a library of components from which you can create your basic designs. Though it is not as comprehensive as CircuitMaker, it does allow you to create your own custom components and add them to the library on the site.

In the breadboard view, a designer can drag and drop visual representations from the library of common electrical parts. In a palette, you can create a new image for a component you need. In this view you can easily create the wiring to and from part leads and breadboard holes using your earlier physical breadboard design as your guide.

The final result in the breadboard view is then converted into a schematic diagram where circuit mistakes are identified and can be corrected. The final result is then displayed in a traditional PCB view, where the user can make modifications to the board size or geometry. Once a design is created, changes in one view are reflected in all the others via an XML schema that links all of the underlying native files.

The Fritzing tool converts the breadboard view into a standard PCB that allows you to define the dimensions of the board you want to create.

The Fritzing tool converts the breadboard view into a standard PCB that allows you to define the dimensions of the board you want to create.

When a part is selected (or added) in a particular view, its icon is visible in all other views and in a commonly displayed parts inspector. There is also a navigator widget that provides a small preview of the other views next to the currently selected one.

Similar to CircuitMaker, the Fritzing site has a library of components from which you can create your basic designs. Though it is not as comprehensive as CircuitMaker, it does allow you to create your own custom components and add them to the library on the site.

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