Arducopter Beta 2.0.38



Please note that the initialization of Gyros was requested to move to the Arming function. This had the unintended consequence of making the Ground Station report erroneous attitude until the unit is armed at least once. This is changed already in the next version 2.0.39 which is still in development. Thanks.


This is a nice update and is recommended for everyone. I've gotten a half dozen flight in with it and have had good success. I'll be incorporating some of the ideas mentioned in the suggestions post over the next few versions. 


What's new:

I reworked the startup so it's much faster. Also, a feature a lot of folks wanted, calibrating the IMU at first Arming is in there. If you hand launch, please do your first arming of the motors on the ground.

I enabled a mode filter for sonar. Not too thoroughly tested performance wise, but it does work. (note, if you rely on the rangefinder class, you must rework your code to be compatible.)

RTL bugs are squashed and it's flying really well now.

Added a special filter in the PID for the derivative term to get rid of the alt hold and loiter issues from noisy sensors. 

Added a completely experimental mode called circle. It will by default spin the copter in a 10m circle from the point at which it was engaged. And it will Yaw towards that point at all times.

Yaw while navigating happens at quarter speed, which was problematic before.

Roll and Pitch Imax are higher 5° than before (.5°)

Logging seems to work now. Please erase the log after installing.

Everything else is mentioned on the SVN.


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  • I did some more ground testing today. I decided to add modes.

    It was found that if the the Altitude mode is engaged while throttle is zero the take off will flip.

    No damage done because my hand was holding the frame.

    Possibly. If throttle is zero and altitude mode is on do not start motors?

    Once in flight the Sonar worked perfect during Altitude hold within 10 inches.



  • jason...
    i can't get good auto level setting on hexa and QC (+) frame
    some diffrent code for auto level between ver 37 and 38?
    now i just using manual level (disarm 10sec)


  • 3D Robotics
    The 3D Robotics terms of service are here:

    Products can only be returned if they're defective.
  • Chris: Since I didn't hear a response from UDrones yet can I just order a new oilpan to have one in the meantime or would that not fix the issue? Is there any sort of return policy if the issue still isn't resolved and it is the APM for some wierd reason and I end up with 2 oilpans?
  • Developer
    Yes it will. I will release it soon. It has some good fixes for Hexa and Tri as well as startup. It won't have the RTL performance enhancement which needs some flight testing.

    I'll have that in the next .40 version. I also plan to implement a trig LUT, which should make the cut on the 1280. I have it built already, just need to merge it and convert it to program flash. That one will be really good, I hope.
  • Will 2.0.39 work with the 1280 ?

  • 3D Robotics

    I suggest you contact Udrones for a RMA to get it replaced. 

  • Chris: If that is the case I'm leaning mostly toward a hardware error. This is every single time. Every time I click the level button it never truely levels. The horizon is always pitched down slightly and a little to the right. I'm not sure how to include pictures here so I guess I'll link to it.

    That is generally the best "level" I can get out of it. I am also aware the GCS goes a little wacko when you don't arm but even after I arm and disarm many times it starts to pitch down quickly and roll to the right and continue to do this and never stop. I'll even reset the level and it doesn't do a thing, it keeps going in circles and circles (while still actively connected after arming). I can see why my craft is so unstable as if I power up the craft and give it gas it tries to auto level itself so if it is pitched right 45 degrees and down the right front motor goes high throttle when the rest are closer to idle. The craft clearly is interpreting exactly what the GCS is seeing. I got this brand new from UDrones and took it out of the package to try it out finally this week and this probably explains why I can't fly it for more than about 30 seconds before I lose authority in 1or2 axis. Can I send this in to get looked at? I had an ARDU platform about 10 months ago I built for a customer and never had a single issue with a self rotating horizon then, it flew great (old Ardupirate).

  • 3D Robotics
    agibbons: Glad it's working for you now. I've added a screenshot of the baud setting to the manual, so it should be harder to miss now.

    As for the gyros, that sounds like more than what the filter pads address. Does this happen all the time? The best way to test is on the bench. In the MAVLink setup tab click on the level button and then check the flight data. It should be rock solid and hardly moving at all. If it's moving, you may have a hardware issue.
  • Chris and Rui: Thank you for the tip on the buad rate for the XBee it works fine now, didn't see it as that is the very last line, maybe you should stick something important like that toward the top. Nevertheless, chalk it up to operator error.

    Now onto my issue I need to resolve, since I have the telemetry working I can see the problem I'm having while flying. The gyros are severely drifting down (pitch forward) so after about 30 seconds of flight, physically level on the craft, it is thinking it is pitching down about 40 degrees hence why my FULL back on the pitch doesn't even hold it steady. Will soldering the gyro filter pads take care of this issue? Once I can get this issue resolved I will be good to go I think. Can I use a conductive trace pen to join these or is it better to try the blob of solder?

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