Some of our designs are freely shared with you, but there are some ground rules you need to follow. Our open source softwares are GNU GPL and everything else freely accessible (unless otherwise noted) is Creative Commons BY-SA licensed. This gives you both rights and obligations.



What are the license terms of the SKAARHOJ designs?

Our open source softwares are released under GPL. Please read the license.

Everything else (such as schematics, PCB designs, enclosure designs, spreadsheets etc. available for download) unless otherwise noticed is released under Creative Commons BY-SA. Please read this page.


How may I use your designs as open source?

Well, the licenses above defines this, but said shortly, you may copy, change and (re)distribute our work as long as you give us credit for the original creation and pass on the work under the same license terms. This effectively means (among other things) that you cannot adapt and redistribute our work without letting the recipient (for instance a customer) know that it's based on open source under the license terms given, which effectively means that there is no way to legally make a "closed product" out of any of it, including your own adaptations.


Can I use your software libraries in my own closed products?

No. A consequence of GPL is that if you use any of our libraries or code snippets from them, your software must be GPL as well. And GPL means that your client have to receive access to the source code for any compiled delivery such as a pre-programmed Arduino.


How should I attribute you in derivative works?

The CC-by-sa license says that you must attribute the work in a manner specified by the licensor (us), but in a way that doesn't suggest that we endorse your work. We specifically ask the following:


  • For enclosures, you must remove our logo from the case, and you must write on a visible place outside (on the back for instance) "Based on work from under the CC-by-sa license"
  • For PCBs, you must remove "SKAARHOJ YYYY" from the PCB and you must place "Based on work from under the CC-by-sa license" on the silkscreen.
  • For documents like schematics, manuals, spreadsheets etc, you must include the text "Based on work from under the CC-by-sa license" somewhere visibly in the document.


How should I attribute you if I use your designs inside my own designs?

This may sound like the previous question, but lets say you fully design your own enclosures for our hardware designs. Or if you develop your own hardware boards and combine with ours. In other words: if a lot of completely original work by you is mixed with works from us. In this case we suggest that you attribute us by stating "Includes work from under the CC-by-sa and GPL licenses" on a visible place for the client. A visible place would be in manuals and on the back of an enclosure containing our designs.


But then, how can I make money?

Sell services. Sell your knowledge and customization services. Sell 24-7 support. Sell documentation. Sell warranty.  We do some of that! It's not possible to charge money for open sourced intellectual property itself, because you are obliged to offer that part to your client for free.


Can I charge a client for an adaptation of your work?

Yes, that would be a service you do for that client. However, the adaptation itself (software, hardware design etc) would have to be licensed under the same terms as the original (GPL or CC-by-sa) and therefore the next client in line (and the public) should have it for free. And of course, in the spirit of sharing you would have made it public available already somehow.


How can I sneak around your license terms?

Hopefully you can't, but in reality there are probably many ways to "get away" with it. But we urge you to consider your deeper motives and attitudes. Although it can be very challenging, give the spirit of sharing a chance and play by the rules. Don't be like the Dead Sea that always accepts but never gives.



Where can I find your free stuff?

Generally, everything that's open and subject to the licenses described can be found on the GitHub repository "SKAARHOJ Open Engineering". The overview, including links to various services, is found on the Free Stuff page.



Why is not all of your IP (Intellectual Property) open?

We wish you asked the question in reverse: Why do you share any of your IP at all? :-) But to be honest, we live in the real world where even nice guys like us have families to feed and we are in no privileged position to ignore basic rules of business. So we need to consider what creates unique value to customers and protect that. At the same time we really truly love to share whatever we can. One particular technology that is closed source is the UniSketch operating system running on our controllers today. It's a good example of our thinking: UniSketch combined with is a unique technology of high value to our customers and our selves as well. However, to a DIYer, UniSketch and would be far more complex to use than what is likely to be gained from it. Since we also cannot provide support for our open source technologies, it would be frustrating for all. But the DIYer can still find many of the libraries behind devices cores as well as hardware schematics and related software libraries online - far enough to build their own controllers. This is a good example of how we can protect technologies of unique value to SKAARHOJ and still share a whole bunch of useful stuff with the world. We hope you appreciate our efforts to keep ourselves in business so we can continue to share!


How can you mix Open Source and closed source?

We can do that simply because we are the copyright owners of our own open source software. So while you can't legally combine our GPL'ed software with closed libraries in your work, we - as the original authors of our open source code - can just decide to dual-license the software to ourselves.