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: 5301

Comment by crystal garris on March 21, 2014 at 9:13am

... stand up to the right of copy in court.

Comment by Gary McCray on March 21, 2014 at 10:54am

Actually, when it comes to the APM / PX----- Auto pilots, there is really a bigger problem than simple Creative Commons - Derivatve compliance.

I am afraid we are trying to "nail jello to a tree".

Basically what the APM / PX's are is a microcontroller hooked to an IMU with some assorted IO.

So is my cell phone, the basic architecture is the same and it is all derivative to some degree.

Good thing nobody (well I hope nobody) is trying to enforce that one.

In particular, what the APM/PX's are is a piece of hardware that supports a specific piece of firmware (which is also open source).

But the firmware is not dependent on that particular or exact piece of hardware.

The further process of integrating that firmware into the Linux - other open source platform BeagleBoard Black as is currently happening even further unseats the firmware from a specific hardware platform.

Ostensibly there will be a dedicated Fire IMU, but the IMU is just the same collection of sensors and IO that pretty much everybody else is already selling on IMU boards.

It is actually hard to see how "derivative" could even begin to apply unless you are claiming first use of any sensor - GPS - Accelerometer, etc.

And I think that ship sailed a long time ago (B3DR).

And since it is open source, anybody is free to make it compatible with whatever hardware.

Aside from direct violation of copyright (3DR name and logo on the card) or trying to claim something as their own private property that was pulled from the open domain I think it is going to be virtually impossible to accomplish legal redress.

Giant corporations like Apple of course, all the time try to convince the courts that they invented and have sole rights to everything (famously a rectangle with rounded corners) after having ripped the foundation of their company off from Xerox PARC a long time ago.

That they are so frequently successful in their suits speaks much more for what is wrong with our legal system than what is their right.

Our boards are in the process of becomming ubiquitous.

More and more Cape accepting ultro powerful microcontroller boards are becoming available as is an ever increasing crop of multisensor IMU boards / capes that cover pretty much all our needs.

And the transition of our firmware to a Linux base pretty much ensures complete democratization of the hardware.

I am afraid Pandora's box is open, and it is all coming out one way or the other.

Comment by Rob_Lefebvre on March 21, 2014 at 11:30am

Gary, pretty good post, except I'd argue that your phone has little in common with the APM or Pixhawk, while the cloned board, even the derivative ones, do.

There's a very important reason for that.  The clone and derivative boards, are being specifically arranged so that they can run the Ardupilot programs in a native way.  They use the exact same chips, arranged in the exact same way (ie: I/O ports are not moved around).  The same is not true for your phone.  You cannot load the Pixhawk hex file onto your phone and actually get it to work.  That demonstrates that there are specific differences.

If the cloners were not simply cloning, then they would have to write their own firmware, port ours (such as the case for Megapirate or Ardupilot on the OP Revo), or create their own HAL build target and ask to have it adopted in the Trunk, which it likely would be if it meets the quality requirements.

But none of those things are true.  At best, they are simply moving some traces around and changing IO interface plug types (HKPilot Mini).  At worst, they just take the APM board files and send them off to be built by another shop, without even bothering to change the screen printing.

Comment by Oliver on March 21, 2014 at 11:58am

I think Gary is right - the cat is out of the bag. And the legal system is a huge mess. So it looks like the legitimate hardware makers are going to have to rely on education and various social pressures, and on building and retaining market share by providing fair pricing, high quality, good service and support, good warranty policies and so on rather than relying on lawyers and cops (the exception being outright counterfeits of trademarks which at least in the US can be dealt with pretty swiftly). This situation has its benefits, as it does favor in the long run companies like 3DR over the dollar-uber-alles outfits like HK, who have to row their boats ever more frantically as they fill to the gunwales with disgruntled customers while trying to compensate by raising prices and bombarding everyone with a stream of emails touting this week's fabulous new product. These outfits sink themselves eventually (Detroit is the ultimate example). They may still be able to bottom-feed, like snapping turtles buried in pond mud, but their customers are then also bottom dwellers who are largely invisible and irrelevant in the bigger picture. 

Comment by Stephen Zidek on March 21, 2014 at 3:22pm

This talks a lot about clones which are not community friendly.  However, I'm more interested in which ones are community friendly.  Could we start a running list of links to cloned APM hardware which is "good"?  I ask because I'm considering starting a new APM project, but the cost of 3DR equipment is prohibitive for me personally.  I'd like to go with a bargain basement product, but reasons like those outlined in this post are stopping me.  Are there any cheap and honest APMs out there?

Comment by Gary McCray on March 21, 2014 at 3:53pm

Hi Rob, I don't actually disagree with you at all and I wasnt proposing that we attempt to use our phones for flying planes with (although I understand a few others have done.

I was simply pointing out from a hardware resource standpoint that there really are many of the same facilities on both of them and there are also many more powerful (but generic) solutions waiting at the gate.

A whole lot of things already have embedded GPS, Accels, gyros and Mags and baros aren't that uncommon either.

And basically what the APM was was a board optimized at the time for being able to support real time autonomous flight an at the time significant hardware requirement.

The PX4 has a lot more powerful and memory full controller, the same (more or less senosrs) and an even bigger stack of IO. 

It is also capable of performing tasks beyond the current envelope of APM firmware (ROS and vision stuff for instance).

And the Pixhawk itself a single board version of the PX4FMU and IO with slightly honed capabilities.

And I am not actually saying I enjoy or condone the bald faced advantage taking by other companies simply out to make the easiest buck they can at our or 3DR's expense.

What I am saying is that given what has come to be a relatively ubiquitous blend of sensors, IO and powerful microcontrollers (now further enhanced with the likes of BBB and Odroid U3) our currtent crop of "flight controller hardware" is facing a rapidly approaching irrelevance.

We are already actively engaged in adapting the BBB with a Fire IMU cape and some of our group are working on the Odroid and there is some independent work adapting our firmware to the BBB with a generic IMU cape.

The APM needed to be superseded for continued growth, but these newer more powerful generic processors promise to have a long growth curve in parallel and they are not going to be held accountable to any one fiscal entity.

I really want to see 3DR continue to prosper, but the simple fact of the matter is that their importance and success is going to be related to their comprehensive support more so than the exclusivity of their hardware.

That is where they have everybody else beat right now and in the future it is going to be crucial.

And of course, because of that continuous support and taking of responsibility, our open community is also strongly supportive of them.

And in response to Stephen above, I say:

You say 3DR equipment is prohibitively expensive. From what Ive seen it costs between 50 percent more and 100 percent more than the cheapest cloners. THAT is not prohibitively expensive, it is a bargain.

As has been repeatedly said in these discussions, what really bugs this community, it's developers and it's question answerers more than anything is to be expected to answer questions about problems that are indigenous to the clone boards.

We truly don't waste our time or our money buying them, why should you or anybody else expect us to waste our time dealing with them.

Our time is valuable too, and we know we get the best most debugged and pretested part from 3DR and it is what we base all our work on.

Comment by Rob_Lefebvre on March 21, 2014 at 3:56pm

Are there any cheap and honest APMs out there?

Not that I'm aware of.

Comment by Andrew Rabbitt on March 21, 2014 at 11:08pm

Interesting debate.  I think Oliver has some very good points.  There's almost certainly not enough margin in any 3DR or other "reputable/honest" hardware supplier's products to fund a full-scale legal rights war on the people who play fast and loose with the IPR.  That is an impossible fight and those folk will always be with us.

3DR et al have to win by providing great service, thorough documentation, forward/backward compatibility as best as can be done and legacy hardware support.  I think they might succeed in part on several of these factors, but in corporatizing the webstore and documentation, they have more-or-less flicked the bird to early adopters and slow learners among us.

When I crash my APM1-piloted airframe, as I'm prone to do, I wind up hunting for replacement bits, cables etc - none of which appear readily available from 3DR.  If the business model forces me to abandon hardware at regular intervals, then I'll be looking to make some savings along the way, somewhere...

Comment by Georacer on March 22, 2014 at 4:01am


You wrote this in your last post:

As has been repeatedly said in these discussions, what really bugs this community, it's developers and it's question answerers more than anything is to be expected to answer questions about problems that are indigenous to the clone boards.

We truly don't waste our time or our money buying them, why should you or anybody else expect us to waste our time dealing with them.

Our time is valuable too, and we know we get the best most debugged and pretested part from 3DR and it is what we base all our work on.

Is DIYDrones.com planned to turn into a community meant to revolve around and support original 3DR products? Why do you discourage people from buying cloned boards so fiercely? Shouldn't everyone be granted the right to place his money where he deems best and face the consequences of his actions?

Comment by hal on March 22, 2014 at 7:55am

Andrew I have been involved with r/c for over 20 years.  I cannot tell you or even fathom the amount of equipment I have given to the recycle or trash bin for lack of repair parts or no longer comparable with the newer stuff.  It is just part of the hobby.  Just this week I tossed 2 "computer" radios from the the earlier 2000's.  They are junk now, and even though I could have purchased a module to make them work with 2.4 their functionality is nothing today.  They were both $500+ radios!  For less than $200 today you can get a 18 channel fully program just about anything radio.  For $300 you can get yourself a major brand computer radio that will outdo the older ones 10x over!  Product cycles are just part of the hobby.  These APM boards are really cheap compared to what they do, how well they work, the software support provided, and the continuing improvements.  It seems now that there are a few different board manufacturers on different projects that the cable and i/o format has stabilized a bit.  Its just part of being an early adopter when the first generation product is no longer comparable with the newer stuff.  How many people still use an Iphone 1 or an iPod original?  Im sure there are some, and they are also no longer supported and no parts available. In another year or two I am pretty sure the APM 2.6 board will be almost obsolete in hardware terms.  It probably is almost there now.  As a result I will end up taking them out and replacing them with the Pixhawk or whatever is the next board coming down the production line.  I will want the features that the new products offer, and the new capabilities of the updated software.  Its just the way product cycles work.  Its not unique to 3dr at all, and I think they do an excellent job of making most items backwards compatible.


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