Rise of the Clones (APM2.x series)



The name 3DR, 3D Robotics, and ArduPilot are trademarks of 3D Robotics.  

The design is Open Source and licensed under the Creative Commons and GPL v3 license.

A misconception is out there that cloning the Ardupilot is not liked.

This is not right, there are a few companies that make Ardupilot gear, and who give back to the community, either in support of developers, or simply adding improvements and Publishing the results for all to see.

What are not appreciated are those who take, but do not give. Who either simply take the Schematics and PCB drawings, directly use these, make equipment, and do not offer support channels or worse, those who make derivatives, and do not feed back to the community.

Recently Hobby king released the HKPilot mini, a welcome derivative to the APM series of boards, this is great news, but there is a catch.  Hobby King did not want to release the drawings.

Here is an email exchange that I have had with them regarding this issue.(please note I have been corrected, the copyright is owned by 3DRobotics)


Me Mar 11 11:47:

Where are the design files for this product? it is Open Hardware, you must publish your design files. This product is copyrighted to DIYDRONES*, and is licensed under the Open hardware licence. This requires you to publish the Eagle drawings.
Under the licence, any derived product MUST be published with the SAME open hardware licence.

Howard T., Mar 14 10:39:

Hello Philip,

Thank you for raising this matter to our attention. For us to help you with your inquiry, we will escalate this matter to our Product Specialist for further assistance. Rest assured that your concern will be addressed shortly. Thank you for your patience and understanding.


HobbyKing Support Team



Ian, Mar 14 18:20:

Hi philip , 
Thanks for contacting the HobbyKing Support Team.

You may contact DIYDRONES for the design schematics. We are not the owner therefore we cannot supply you with the design

Thanks for emailing support. 
If you have any other questions, please let me know. 
Best Regards. 
HobbyKing Product Specialist 

 After other exchanges, including posts on the product page they posted the following.


   Proficnc 11 points - 11/03/2014

   design files please


      Eagle CAD files will be uploaded shortly in compliance with the user agreement

      proficnc  11 points

      Thankyou :)

Which was great…. Except they did not post the files.

After another day of many people sending support requests, finally they sent an Altium file (Just PCB, and with exploded polygons).  This File was a modification of the Altium file I had posted on DIY Drones of an early 2.5 revision (mistakes included J ) which does appear to be the board that they have built.

But the problem? According to the licence, they MUST abide by the licence.

  • ShareAlike — If you remix, transform, or build upon the material, you must distribute your contributions under the same license as the original.
  • Attribution — You must give appropriate credit, provide a link to the license, andindicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.

So that means that Altium is OK, as that is what they used. But they MUST include the FULL design file. That is Schematic, Lib files, everything needed for others to go straight into production with this file, and it should have this license clearly marked, and it should show it is a derived work.


* The name 3DR, 3D Robotics, and ArduPilot are Trademarks of 3D Robotics.  

The design is Open Source and licensed under the Creative Commons and GPL v3 license.

The Pixhawk / PX-4 has the open Hardware licence, please see the link below for details...


1. Documentation

The hardware must be released with documentation including design files, and must allow modification and distribution of the design files. Where documentation is not furnished with the physical product, there must be a well-publicized means of obtaining this documentation for no more than a reasonable reproduction cost, preferably downloading via the Internet without charge. The documentation must include design files in the preferred format for making changes, for example the native file format of a CAD program. Deliberately obfuscated design files are not allowed. Intermediate forms analogous to compiled computer code — such as printer-ready copper artwork from a CAD program — are not allowed as substitutes. The license may require that the design files are provided in fully-documented, open format(s).


If you do not wish to release your drawings, then you must start with a clean slate, the reality is, if it is compatible with APM/PX4/Pixhawk, it is most likely a derivative. (Exceptions would be TauLabs/OpenPilot; APM code will run on their boards, but only after significant modification to the code)

Why is this important?

DIYDrones is a community where people with a common interest share their ideas, and inventiveness. It is important that the work done by those in the Development process is recognized for its worth. When someone comes along and taps into that knowledge, makes a gain from that, and does not return to the community, it takes away from why we are all here.

I have heard people say “I do not want to open source my product based on APM, because people will copy it…..” the reality is, without the open nature of the project, this person would be unable to economically design their project in the first place, so feeding back to the community is a small price to pay.

For those interested, have a look at the git-hub repositories, there are a number of hardware suppliers supported by the code base, and the development team, these manufacturers get direct support from the whole team, because they are OPEN with their code additions, and also with their hardware.

When purchasing hardware, consider this,

  1. does the company you are purchasing from directly support the product?
  2. does the company seek to improve on the product, and release this information for the community to use?
  3. do profits from the sale of the product go towards creating better outcomes for the community in the longer term?
  4. does the company have quality control?
  5. does the company have engineering on hand to help with your log analysis?

This Blog will be moderated. All posts will require approval. 

Views: 5309

Comment by James on March 22, 2014 at 6:01pm

My comment might cause quite some trouble but..

What is a clone and what is original? For an open source project which schematics, design, codes are all open and free for all. There shall not be the "official" vs "clone" talk, every piece of hardware are on the same ground. The only difference here is, APM is a project ORIGINATED by 3DR and evolved under 3DR's control/contribution. Somehow or another, the development team is quite closed/under control of 3DR until today. (dev google group, github main managers are pretty much own by Chris.) Also, when speaking of support from third party hardware maker, so far what has been seen is fierecing rejection. Let's put it this way, if one hardware maker comes up to the community to say, "hey, we would like to support the project in trading of the recognition. But we might not be able to help with software dev. What we can do is improve/derivate hardware and donate partial profit to the community. It might not be as much as 3DR.(there is a significant price different between the so-called clones and 3dr, already)." ... I really would like to hear what does the community have to say about it.different group has different capability, you can't simply blaming them not bing helpful or whatsoever...

 will the community take it and offer proper recognition? 

Comment by Andrew Rabbitt on March 22, 2014 at 8:05pm

jg,  You both miss my point and make my point in the one post!

I don't equate my APM1 with a 10-year-old radio.  My earliest APM1280 is barely 3 years old.  Sure, they're "cheap" for you, but for some of us, we need to stretch the effect of our cash.  Now if rapid obsolescence is the 3DR business model, I'm not happy to support it with wads of my hard-earned.

Anyone would think the APM had ceased to function the way some talk, but in my opinion, there is a lot of life left in the old girl yet and I believe the (fixed wing) flight control model is, frankly, a bit noddy.  This is one area where leaps and bounds could be made without resorting to monster processors and memory on shiny new hardware.  That's something I am working away at for my own amusement.

Anyway, to make my earlier point clearer, if 3DR et al continue to release their hardware designs under GPL they must offer something additional to those who, lets face it - even when playing by all the rules, can take the design and produce it at Chinese prices.  This is what I'm getting at.  It's the something else that will make me buy 3DR over E-bay specials.  If what I buy today is effectively unsupported in six months time, I fail to see what 3DR is offering, given that it is open-source after all...

Comment by Philip on March 23, 2014 at 4:27am
@georacer. Read the blog again. Cloning is not discouraged, but complying with the terms of the copyright is encouraged.
Anyone is welcome to design another autopilot board, and if the community likes it, or you have the skills, then get a HAL layer done, and you have an APM compatible Autopilot... Greatly encouraged......

Comment by Philip on March 23, 2014 at 4:32am
@james the term was original, not official. When you take a design you did not do, and produce it, you have a clone. This is not discouraged as you say, if the terms that are on the original are complied with.

Comment by Philip on March 23, 2014 at 4:50am
@wayne. GPL 3 covers those issues raised for software... This blog is discussing the hardware. There is no confusion as to the derivative nature of the HK mini.

I wonder if a hobbyking HKpod, 10% bigger than the Techpod would be ok? Is that a derivative?
Comment by Rob_Lefebvre on March 23, 2014 at 5:12am

James, the answer to your question is very simple:  "Yes".  

If one of the alternative manufacturers would like to do something, anything, no matter how big or small, to support the community, it would be gratefully accepted.  But as it is now, not a one of them has done anything beyond selling clones at bargain basement prices, with zero support.

They've not submitted a single pull request, or even a line of code, or even an actionable bug report.  Nor have any of them fixed any of the mistakes on the APM design (level shifter, power supply, etc).

While one of them does employ some people to provide some customer support, they seem to have chosen people with highly questionable technical skills, and even worse people skills.  It just leads to further confusion and an even worse experience for their customers.

Comment by Rob_Lefebvre on March 23, 2014 at 5:14am

@Andrew:  Which APM hardware has ever been obsoleted?  Last I heard, Arduplane still worked on APM 1.x series?

Comment by Bertold on March 23, 2014 at 6:09am

I have a question about this.

I thought a hardware design is not covered by copyright. The blueprint is, of course, but the actual manufactured product is not. From US Copyright law (it's the same in most countries, but this one is available in English and I don't want to try to translate the legal text as I will probably subtly change the meaning without knowing): "In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work."

Therefore, I would think the open hardware license would give you the right to reproduce the schematics and other design files without asking permission from the author providing the conditions in the license are met. Hardware made from the schematics is unrestricted I think, as these are protected by patents rather than copyright. Obviously using the 3DR trademark on a board that is sold in a country where it is valid is not legal, but that is the responsibility of the buyer/importer, not the manufacturer or seller.

Distribution of the GPLv3 blob without source is not OK, but I think they sell them without software requiring the user to flash APM.

Comment by hal on March 23, 2014 at 7:35am

Andrew 3dr does offer something different.  If they didn't people wouldn't buy their product over one that provides the same function at less cost.  3dr provides and pays for this forum, 3dr pays for staff that write code now for their hardware products, 3dr continues to improve the hardware and the software and YOU and EVERYONE else gets to use it for FREE.  3dr also has made their programming backwards comparable where they could.  I fly arducopter so I cannot comment on the functionality of the arduplane.  But the functionality and reliability of arducopter has now met and exceeded the big closed source hardware and software manufacturers.  They have achieved this with the help from the community and money from their own pockets.  The cost is far less than half to buy and fly an APM system compared to another closed source system.  I chose the APM platform because I do not like manufacturers telling me what I can and cannot do with my system.  I don't want them making safety or programming choices for me.  I want to be able to customize my system to exactly what I would like it to, or need it to do at the time.  Opensource projects pool resources from a larger population of people, and a larger group of ideas.  They are tend not to "group think" as much if there is a problem.  Look how fast the project has grown, look how fast the community has grown, and look at all the new features in alpha/beta and compare those to any other companies offerings.  And you get it all for 3dr just asking you to buy their hardware, and if you decide to buy a clone, please contribute to the community to improve the project for all of us.  Then maybe someday you will realize there are differences in quality of parts and production and purchase a genuine 3dr product.  It doesn't get any cheaper than FREE!

Comment by Philip on March 23, 2014 at 1:35pm

@jg, you comment to Andrew is spot on.  If people actually think that an Autopilot of the level of APM or Pixhawk could ever have been built at the current price-point without opensource, they are kidding themselves. these systems are truly amazing value.


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