Hi All,

I was recently fiddling around the code for a while and decided to create a tutorial out of it so that others may find it useful. If I would have known this knowledge long back, I am sure I would have saved a lot of time since then! I find lot of beginners getting swayed and lack of knowhow on MavLink with respect to APM/PX4. Information on internet is scattered and not much of use!! 

This will be "Step by Step" entertaining, PART - I of the series I plan to write.on:

What it Covers:

  1. MavLink, starting from scratch. What the hell is it and understand how it works with APM/ PX4
  2. Learn how developers think -> Arducopter communication with Mission Planner and vice-versa.
  3. Get a feel of 'How Stuffs works'.

Too much hype:) Well, this information has been collated from my experience and from internet. I know there is information on the new Wiki, it tells you what, I plan to tell you 'how'! :)

Please let me know if you found it interesting. If there is enough response, I will make another tutorial where I would add more 'Step by step' knowhow!!


- More on MavLink

- Learning Arducopter source code, Step by Step

- Making swarm (multiple) copters work with your 3DR Telemetry radio! I am working on it.

See attachment for [MAVLink Tutorial for Absolute Dummies (Part –I)]

Edit: Request you to post your queries over the forum directly, as it is not possible for me to address all queries I get by email!


Best regards,


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Timing is perfect. :)

Love the idea, thanks for doing it, its absolutely something i am interested in learning

Thank you for this it will be very helpful to me and keep up the good work and pass on all that you can as I need help with the 2.5 best regards ,


Thank you for your feedback so far :) This will be applicable to both APM series and PX4 series as they share the same code base for GCS and Autopilot, so should be valid for next many generations to come :)

I did try to review it well before posting though for anything that may be unclear, typos, or additions, your comments are more than welcome!

Thank you, about bloody time. I have put dust covers over my Ardu and am using my KK2 instead. The uploading of information from computer to the flight controller is too complex, not all of us out here are computer nerds. I got 32 flights from the Ardu and then it refused to arm so now I am stuffed! How about a Mission Planner lite so that we can just fly instead of playing around with endless parameters that we don't understand.

Thanks for making a start Shyam

i would also like to know more about SWARM  screen

He he...

i agree !!!

Exactly what i was looking for !!!

Thank you Shyam for your time and effort.

Hi All,

    Please use the current updated version of the document and have renamed it for your  

    reference to _v.1.


There is no dedicated Swarm screen on MP. The current software design is meant for 1 GCS to 1 copter, so this would have to updated in software design.

Also, the 3DR radios do not support multiple communication, as IMHO, it is Send all <-> Receive all based link that is used. So all nearby drones will listen to all 3DR radios in the surroundings. I am not sure, it different frequencies for each 3DR radio is supported/ can be configured.




What is the Screen that comes up after you press Control F in Mission Planner, i thought that was the Swarm Screen?

I was also under the impression that by changing the Net ID in a 3DR telemetry Set, that would cause your 3DR telemetry to be a unique ID, thus allowing the use of Multiple 3DR Telemetries 

Hi @MightyThor,

You are right about the Ctrl+F Swarm option. As it is still in beta, I guess being the reason that it is not moved to make it into one of the tabs so not many know about it! I have tried adding two quads to that but it is still not clear to me on how to use it as I haven't looked into it much yet.

About the NET ID, you are right, can be changed as I read but haven't tried myself though. I am not sure if it changes along with it its frequency because that is important. To me it looks like, it is like changing the system ID of the component being used inside. This would still mean all packets from one telemetry goes to all drones and causes packet over flooding.

If you or someone could confirm about the frequency part, would be helpful.

In the USA we can only use the 915 mhz Frequency, out side the USA its 433  mhz, so i doubt a frequency change would Occur. Changing the NET ID gives enough uniqueness, as i understand it, to Send commands uniquely to each 3DR receiver. I will be setting up a second Quad this weekend, so i can verify the Change in NET IDs

Do you have the Link to Download Mission Planner Code? i am looking for the Zip FILE, i have an interest in changing a few things like Loiter turns, i'd like to see if it can support a Start Altitude param and a Finish Altitude Param

I also would like to Look at the Code in the Swarm Screen.

Hi @TheMightyThor,

It would be nice to have your real name :)

I use Visual Studio 2012 in Windows to build MP code on Windows (source code link from github). VS 2010 somehow has some issues with some libraries. There are also instruction here. I didn't try to build on my Linux yet. Using Arduino is no good, with Visual Studio, change, compile and upload has faster development advantage.

If you have any issues understanding MP code, you can mail me, I will try to sync with you.

Sure, do keep me updated with your findings :)


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