“I am opposed to the laying down of rules or conditions to be observed in the construction of bridges lest the progress of improvement tomorrow might be embarrassed or shackled by recording or registering as law the prejudices or errors of today.” Isambard Kingdom Brunel (1806-1859)
After you have been building your circuits on prototyping board for a while you are bound to begin considering creating your own PCBs. While this may initially seem to be a daunting prospect it is surprising easy to produce your own circuit boards. The availability of low cost PCB manufacturing services now means that it is possible for a hobbyist with a modest budget to create high quality PCB designs. The CAD tools necessary to design these boards have become increasingly accessible with a number of free and low cost packages available online.
In order to make your first PCB there are a number of points that you should consider if you are not to become frustrated by the process.
Cost – While there are a limited number of free software tools there are also a number of low cost options that are well within the reach of the average hobbyist’s budget. These low cost packages tend to be stripped down or ‘lite’ versions of professional packages and are well supported and maintained. Within this article I have looked at the free and low cost CAD tools that meet a budget of $500 – we are looking at a hobby here after all!
Platform – I personally use Windows as my development OS so I have mainly looked at software running on the latest Windows versions. I have mentioned below if the software is also available for Linux.
Support – You are about to embark on learning a new software tool and you want this process to be as easy as possible, with an intuitive interface that should allow you to begin making progress quickly. If you run into problems then an active online community and forums are useful source of assistance that you can refer too; so these need to be reasonably well developed.
Design Complexity – If you use a ‘lite’ version of a tool you need to ensure you appreciate its limitations. These are normally defined in terms of board dimensions, number of layers and/or number of device pins. What is the size of your ambition? If you are looking to develop simple, small PCBs then your tool choice is larger than if you want to develop multilayer Eurocards.
Commercial Use – You should also consider if you are going to turn any of your projects into commercial products. Many of the commercial software tools are provide as ‘lite’ variants with the specific licensing constraint that they are may not be used for commercial gain. For example Eagle provide a version with the same capabilities as their Standard package for Hobbyist at 1/3 of the price but you are required to sign a disclaimer stating that you will not use it for commercial gain.
Based upon an investigation of the most popular packages on the internet, and drawing on my own personal experience, there are six CAD tools that I believe you should consider if you are looking to start designing your own PCBs. Each of these tools has their own strengths and weaknesses that will effect your selection. The six I would recommend you consider are:
- DesignSpark PCB (RS Components)
- DipTrace 300 pin Freeware (Novarm)
- Eagle Freeware (CadSoft)
- Easy-PC (1000 pins) (Number One Systems)
- KiCAD (KiCAD PCB)
- Target 3001! Discovery (ibfriedrich.com)
Two of these are free packages which are unlimited in terms of size of board, pin number and layers. Four are ‘lite’ versions of packages that have limitations but they provide you with a migration path should you wish to upgrade to a more complete package at a later stage. These packages have the advantage that the time you have invested in learning is not wasted when you want to do more complex designs.
DesignSpark PCB is a CAD tool which is specifically branded for RS Components/Allied and created by Number One Systems which means that is has the look and feel of Easy-PC. DesignSpark PCB is completely free and the tool can be used for commercial project as well as by hobbyists. This is very useful if you decide at a later point that you may want to exploit your design. There are no constraints on the size of the boards or the number layers that you can create and there are some excellent features including autorouting and autoplacement for components. There is an excellent online forum and RS Components/Allied provide an extensive library of parts based upon their catalogue. There are also a number of tutorials online that will help you get started which are accessible through the RS Components website.
As this is a branded product there is advertising within the tool which includes default parts properties relating to RS Components/Allied specific feature, but this is a small price to pay for such an excellent tool. I have personally used this tool for commercial product development and I found the online support to be excellent. DesignSpark PCB does not support operation on either Linux or Mac OS whichwill exclude it from you choice if this is your preferred operating system.
DipTrace is a professional CAD package that is available as a freeware version. The freeware version is limited to 300pins and 2 signal layers and is only for non-profit use. Although it is limited in this regard it is still fully featured with access to all of the standard part libraries (100,000+ parts). The website provided an excellent Guide Tour of the features and capabilities of this tool and as you would expect it is of an excellent standard. DipTrace runs on Windows, Linux and Mac OS X so a version should be available for your development platform.
As this is a professional package it can appear a little bit daunting to a beginner but it is well documented with a good help and an extensive PDF tutorial. There is, however, less support available on-line, which is not entirely uncommon for commercial packages. Should you want to extend your designs then you will need to purchase one of the more extensive versions. There are four to chose from, Lite, Standard, Extended and Full. These range from $145 up to $895 for the Full version which provided unlimited signal layers and pin counts.
This is an excellent tool with all the features you would expect from a professional CAD platform including autorouting and customisable autoplacement. While it has a steeper learning curve than some of the other packages the migration path to other versions means that the time you invest in learning how to get the most from this tool would not be wasted in the future.
Eagle Freeware is similar to DipTrace in that it is an entry level variant of a family of professional tools. Where Eagle differs from DipTrace however is in the level of adoption it has achieved amongst the maker and hobbyist community. If you need to progress beyond the freeware version which is limited to a usable board size of 80mm x 100mm, 2 signal layers and a single schematic sheet then they offer Eagle Hobbyist. The Hobbyist allows 99 schematic sheets, 6 signal layers and 100mm x 160mm board sizes. You need to sign a form guaranteeing that you will only use the version for non-commercial use before they can process your order. Alternatively the Eagle Standard edition can be purchased with the same performance for $820 for a single user license.
Eagle Freeware includes an autorouter but no autoplacement tools. It is a very nice tool to use and as previously mentioned it has extensive support among the maker and hobbyist community with a large number of online forums and tutorials. Eagle is also supported by Farnell/Newark with Element14 acting an affiliate. This means that Farnell/Newark now include Eagle CAD data on their website for their components and the tool will allow you to link to them for the generation of bills of materials. Eagle CAD is also the CAD tool of choice for a number of online forums providing open source hardware design.
Eagle CAD is available for both Windows, Linux and Mac OS operating systems.
As previously mentioned Easy-PC is created by Number One Systems who also provide DesignSpark. Unlike DesignSpark, Easy-PC has a pricing model in line with Eagle and DipTrace. The entry level version is limited to 1,000-pins and costs £247. For this you get the integrated schematic capture and PCB layout tools but the Pro-Router is an additional tool that costs a further £197. Similarly the component part libraries are additional cost items. While this is an excellent tool it is more squarely aimed at the CAD professional but I have included it here in part to highlight the real value of DesignSpark. It should be stressed however that the underlying database structure does not allow DesignSpark designs to be edited with Easy-PC!
Nevertheless Easy-PC is still a relatively low cost entrant into professional CAD tools and has an excellent 3D viewer. Easy-PC is a Windows only application so will be of little interest to anyone working with Linux or Mac OS. If you are aspire to create larger, more complex designs that will require a fully featured CAD Tool then Easy-PC is well worth considering.
KiCAD is the only open source CAD tool that I have included in this review. It is made up of four separate tools; a schematic editor (Eeschema), PCB edition (Pcbnew), Gerber file viewer (Gerbview) and a footprint selector for component association (Cvpcb). It will allow you to design boards with up to 32 copper layers and also includes an extensive library of 3D models. It has been developed to run on Windows, Linux and Mac OS X and is released under the open source GNU GPL v2 license.
KiCAD is a very competent package and while it is open source it is feature rich and easily competes with some commercial CAD offerings from other vendors. It is primarily aimed at professional users and it is hoped that over time it will prevail as the preferred CAD program within the industry. As such it does not provide a great deal of support for the maker or hobbyist user. There is a reasonable level of documentation online with tutorials and if you have used a CAD tool before then you are likely to be able to pick up this tool relatively quickly. It may, however, be too daunting if you are a complete novice to PCB CAD.
It includes an autorouter and a reasonable collection of component libraries along with a 3D viewer. This is an excellent tool and you are not limited in the size of the PCB you can create so if you are able to overcome the lack of support then you have a tool that will meet you needs well into the future at no cost.
Target 3001! Discovery is the freeware version of a family of seven packages which increase the number of pins, copper layers and simulation nets. These range in cost from the $79 to $4,169 but the ones that makers and hobbyists are likely to be interested in are the Discovery (Free), Light ($79) and Smart ($249) versions. All three versions are limited to 2 copper layers but have increasing pin counts of 250, 400 and 700 respectively. The last version is the only one that can be used for commercial purposes.
Target3001! includes both an autorouter and an autoplacer along with a mixed mode simulator based upon SPICE. This is an exceptionally well featured CAD tools which is very popular in Europe with multi-language support for English, German and French. It has an excellent online help and tutorial videos available through the website. The mixed mode simulator is a real bonus in this tools and while the user interface is slightly more simple than the other packages discussed it is still an excellent offering.
Target 3001! PCB
The choice of package you use will very much depend upon what you are looking to achieve and I hope that the information above will provide you with a better idea of what each tool has to offer. I personally use DesignSpark as the initial designs I did required a fairly large board with a large pin count.
If you normally design small board with limited layers then Eagle is probably the best choice as it has an excellent online community with many designs already available as open source hardware that you can amend for your projects. I also think that KiCAD is an interesting offering which I would consider using myself if I had not already built up experience with DesignSpark. What appeals to me about KiCAD is the unlimited nature of the tool which does not constrain your ambition.
Whatever tool you chose download it and have a play – you will quickly get a feel for what you can do with it and how likely it is to meet with your needs.
Designing you first PCB is an exciting process and you will get an immense feeling of satisfaction when that first board falls through your letter box – so don’t waste any more time and get making!