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Licensing Matters

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Why engineers should care about licensing hardware designs

In this post we take a look at open source licensing and in particular when used with hardware designs, rather than software. Of course, hardware can include software—or “firmware”— elements, but the case being made here is of the importance of providing explicit licensing information with a design if you intend for it to be freely used, and improved upon, by others.

A clear signal of intent

Back when we only had top-down media, such as books and magazines, things were much simpler. A publisher would have to be clear about the rights associated with a design they printed, and for simpler DIY circuits found in hobbyist magazines it was probably safe to assume you're free to do with them as you please (but perhaps not reprint them verbatim!) The same could also be assumed for reference designs such as those provided by semiconductor manufacturers — after all, why would they not want you to adapt them for use in 101 different products all using their components.

Nowadays things are a little more complicated and you might find a design online via any one of a number of websites, forums or wikis, or be sent something via a mailing list. Unless explicit rights are conveyed with the design, what can you do with it? The answer may be nothing. It's possible that you could build something from a schematic diagram or a PCB layout, or re-capture or re-lay out these in an attempt to get around the copyright in the design. But the design may embody other rights, e.g. patent, and there remains potential to land in hot water if your action is discovered.

Thankfully, if you want to share something with a wider community and to encourage reuse, we have open source licensing to facilitate this. It may not always be perfect but at the very least it serves as a clear indication of intent, and says that your happy for your work to be used in a given way, but perhaps subject to certain conditions.

Copyright licensing

Open source licences are mostly concerned with copyright. When you make a creative work such as a schematic, board layout or code, you hold copyright by default, and an open source licence can then be used to grant liberal rights to third parties.

In addition to granting rights, open source licences tend to include a disclaimer stating that the work is not warranted to be fit for any particular purpose. You wouldn't want someone trying to sue you for lost earnings, or worse, that they claim are a result of making use of your design...

It's also worth noting that there is an Open Source Definition which sets out the specific criteria for open source licences. If a licence does not meet the criteria, it cannot be called open source.

Major licence types

There are many open source licences and it would be easy to dedicate an entire post to dissecting a small selection of these. Rather than do that, it's sufficient to say that there are “copyleft” licences, where the rights granted are hereditary, permissive licences which pretty much say do as you please, and those that sit somewhere in between.

When a copyleft licence is being used, the copyright holder is granting you rights but under the condition that you grant the same rights to others if you distribute a modified version of their work Hence the “hereditary” part — the rights flow with the design and, in theory at least, cannot be taken away.

Permissive licensing is as the name suggests, and generally allows people to do as they please with the design.

Hardware != software

It must be pointed out that there are practical considerations when using copyleft licensing with hardware designs. In short, it may not be as anywhere near effective in ensuring that the liberal rights flow with a design and across 3rd party revisions etc, as when used with the source code to computer software. Lawyer and open source licensing expert, Andrew Katz, wrote an excellent blog post explaining why.

Since hardware designs tend to be pictorial in form, e.g. diagrams, rather than text, the open content licences from Creative Commons (CC) are a popular alternative to using licences that were designed with software in mind. One important thing to note here though, is that not all CC licence variants would be considered to be open source, as some fail to meet the aforementioned criteria. For example, an “NC” type licence which stipulates no commercial use would clearly discriminate against field of endeavour.

More recently, we have also seen the creation of licences that were designed specifically for use with hardware. Such as the TAPR Open Hardware Licence, the CERN Open Hardware License, and the Solderpad Hardware License.

Have you the right?

Before you can go granting rights to others you must first be certain that you have the rights required to do so. If this concerns something you designed outside of work, and your employment contract does not stake a claim on things you work on in your own time, this is probably straightforward enough and you're likely free to do as you please. But if, for example, this concerns something you were contracted to work on for an employer or a customer, it's quite possible that they will not want this sharing in such a way — at the very least not without first being consulted!

Whenever there is uncertainty, before you go publishing materials under any sort of licence, you must make the appropriate checks, e.g. with your manager, company legal counsel or a customer.


When it comes to the rights associated with creative works such as a hardware design or source code, the worst possible position is one of uncertainty. Whether you mark a work “all rights reserved” or publish it under an open source licence, you are working to remove uncertainty and to manage expectations. This can save you, and others, a great deal of hassle further down the line.

There are a lot of open source and open content licences available, and which one is the best fit for a particular project will depend upon criteria including the motivation for taking such an approach and, to some extent, personal tastes. And if you are looking at using open source licensing in a work context, it would be strongly advisable to consult company legal counsel.

NOTE: I am not a lawyer and this does not constitute legal advice!

Open source (hardware and software!) advocate, Treasurer and Director of the Free and Open Source Silicon Foundation, organiser of Wuthering Bytes technology festival and founder of the Open Source Hardware User Group.

20 Apr 2012, 9:24