Arducopter 2.1 release

Ardupilot 2.1 is out and can be downloaded by the mission planner (or with Git). You must have the latest version of MP to be compatible. If you're compiling with Arduino, you must use the "mrelax" version of Arduino that is in our downloads section. This is because Arduino was never tested with code larger than 128K. And since our code is probably the most complex Arduino project ever, we found the issue. This altered version of Arduino allows you to specify a special compiler flag that makes it work again. Otherwise it's functionally identical to version 22. When we transition to 1.0 of Arduino, you won't need to use a modified version, since they have patched it for us.


This version has a few new features, but is mostly a bug fixes and compatibility with APM2.  The nav routines have been updated and well tested. I'm getting very reliable results now. 

One new feature that I snuck in was SuperSimple mode, which re-calibrates simple mode when you are flying with GPS > 20m from home. It allows you to fly in any direction in Simple outside of this radius. Check the wiki for more info.

Added Auto_land mode to help with Failsafe implementations.


Here's a video I took flying WPs using CH 7 to toggle record them. I flew back and forth over the park to se how straight a line I could maintain and how repeatable it was, then I recorded a few waypoints to the left and right, then I recorded a landing wp by toggling CH7 when the copter was on the ground. The landing could be improved, it was trying to maintain a location and didn't level out in the last meter to the ground as it should. I was missing the screw holding my Arm in place so it folded in just a bit, no real damage done. BTW, this video is W/O a sonar.


The next video is of the Loiter control. I improved loiter a bit with a bug fix and the stability patch from the stabilization. Wind was mild. Could be tuned just a little higher.



Here's a video from Dec 17 showing WP recording. The radio was on the ground the entire video. The 3DR frame did not have a sonar on it. The landing was recorded as well.



Tridge wrote a Geo - fence routine to restrict flight within a certain area for Arduplane. We'll port that over to AC. You'll be able to fly acro inside a safe area and have it go into AP if you loose control!

We need one more pass to finalize the Optical flow integration.

Finalization of the Z Accel code.


Have fun and fly safe,




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  • Marry Christmas, Happy Hanuka, Peace and love from the Holly land 

  • Navigation.pde             last update in GIT


    in the new "calc_XY_velocity()" you wrote:

                 x_GPS_speed  = (last_longitude - g_gps->longitude) * dTnav;
                 y_GPS_speed  = (last_latutude  - g_gps->latitude) * dTnav;

    Should not be "/dTnav" instead of  "* dTnav;"  ?;


  • For people having the "Projects for repository type could not be loaded as the type could not be found" ... remember you need to install the subversive plug-in in Eclipse to make the psf file work.


  • A little while ago I was also asking if arming/desarming motors could be done with a switch.

    Some people said this was too dangerous to implement.

    Well, I'm using this feature now on my MultiWii (version 1.9) and I have to say it's great!!

    Only when applying no throttle the motor can be armed and disarmed.  So there is no danger of disarming the motors when flying or arming the motors when the throttle is up.

    Maybe this could be integrated in the code afterall?  Not everyone would have to use it ofcourse, only those who want to.  So maybe this option can be activated in the user settings?

    I hope you (programmer) guys would think about this.

    Merry X-Mas to you all!

  • I've read about some problems (APM freezing) when this software (2.1) was launched.

    A few people had crashes because of this.

    Have the problems been solved?

    Is there a stable software version out now?

    Or do we have to use previous versions like 2.0.49 for the time being?

  • What is the difference between the 10x45 that came with my kit from jdrones and these 12x47sf apart from the obvious lenght?  Advantage or disadvamtage of running them with my 100% stock quad?  Im a buyer.. In Montreal

  • Loaded dev 2.1 with AF02 mod, and on first flight with stabilize and simple mod, after around 15 secs of hovering manually, she rolled left around 30 degrees and crashed..  it was a stable descent not wobbly or anything...  Could not recover.  Input right all the way and made zero difference..  Im a noob since last monday in flying but havent crashed once in a dozen flights.. :(((   The prop with the most damage had the top screw loose.  Not sure if this was the cause of the crash or software because I tighten the props with the tool and check every flight..!  Or possibly the sudden stop of the prop caused it to loosen itself..  Thats what im thinking because if the prop was loose, it would not of sustained that much damage as it would have been almost free with not much resistance..  Any input on this?

    any difference that its winter here and -14c??  been flying all my flights in subzero temps since I got her..

    ordered 6 sets of props lolll

  • hi all

    testing my hexa right now at the field :) one major thing i am noticing is that the YAW is always sticking left or right and then becomes almost impossible to stop if from yawing, its like its dancing in the air! at times yaw doesnt even respond. any one got an idea of what it could be?


  • Developer

    Here a video of the LOITER mode test with the firmware ArduCopter v2.1 + AF02 mod from afernan

    I have used the emile fix for the calculation of the ground_speed

    Front wind: 19 Km/h gusting 30 Km/h

    LOITER PID: P=0.4, I=0.01, Imax=25

    Regards, Jean-Louis

  • I plan to fly the custom arducoper tomorrow with a little more air authority with the propeller motor combination :

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