Copter-3.3 beta testing

Warning #1: an issue has been found with Tower's Pause button which can cause the vehicle to fly to an old position if the vehicle has not sent a position update to Tower in some time.

Warning #2: Copter-3.3.2 fixes a bug found in Copter-3.3.1's desired climb rate initialisation which could lead to a sudden momentary drop when switching from Stabilize or Acro to AltHold, Loiter or PosHold.

Warning #3: Copter-3.3.2 fixes an issue found in Copter-3.3.1 which could lead to hard landings in RTL or AUTO if the WPNAV_SPEED_DN was set too high (i.e. >400 or 4m/s) and/or the WPNAV_ACCEL_Z was set too low (i.e. <100 or 1m/s/s).

Warning #4: a bug was found in Copter-3.3 which could cause a sudden crash if you abort a Take-off initiated from a ground station.  Video description is here.  The bug is fixed in Copter-3.3.1 so we recommend upgrading.

Note #1: AC3.3-rc8 corrected a long standing bug in the HDOP reporting.  HDOP values will appear about 40% lower than previously but this does not actually mean the GPS position is better than before.
Note #2: if upgrading from AC3.2.1 the vehicle's accelerometer calibration needs to be done again.
Note #3: set SERIAL2_PROTOCOL to "3" and reboot the board to enable FrSky telemetry like in previous versions.
Note #4: the wiki will be updated over the next few weeks to explain how to use the new features

Copter-3.3.1 is available through the mission planner.  The full list of changes vs AC3.2.1 can be see in the ReleaseNotes and below are the most recent changes since AC3.3.

Sadly this version (and all future versions) will not run on the APM2.x boards due to CPU speed, flash and RAM restrictions.

Changes from 3.3:

1) Bug fix to prevent potential crash if Follow-Me is used after an aborted takeoff

2) compiler upgraded to 4.9.3 (runs slightly faster than 4.7.2 which was used previously)

Changes from 3.3-rc11:

1) EKF recovers from pre-arm "Compass variance" failure if compasses are consistent

Changes from 3.3-rc10:

1) PreArm "Need 3D Fix" message replaced with detailed reason from EKF

Changes from 3.3-rc9
1) EKF improvements:
    a) simpler optical flow takeoff check
2) Bug Fixes/Minor enhancements:
    a) fix INS3_USE parameter eeprom location
    b) fix SToRM32 serial protocol driver to work with recent versions
    c) increase motor pwm->thrust conversion (aka MOT_THST_EXPO) to 0.65 (was 0.50)
    d) Firmware version sent to GCS in AUTOPILOT_VERSION message
3) Safety:
    a) pre-arm check of compass variance if arming in Loiter, PosHold, Guided
    b) always check GPS before arming in Loiter (previously could be disabled if ARMING_CHECK=0)
    c) sanity check locations received from GCS for follow-me, do-set-home, do-set-ROI
    d) fix optical flow failsafe (was not always triggering LAND when optical flow failed)
    e) failsafe RTL vs LAND decision based on hardcoded 5m from home check (previously used WPNAV_RADIUS parameter)

Thanks for your testing!

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –


      • Randy, did this get put into rc6?

      • You guys are awesome! Coming to arducopter from other platforms was  worrying at  first - you always wonder what features will be different, but I'm very impressed with how thorough you guys are in both design and resolving issues and implementing new suggestions and features. This project fills me with a sense of excitement! A definite pat on the back to all involved. 

  • Is anyone having problems with Teensie working on their Taranis/X8R/X6R on 3.3?  I just set it up, but there is no data feed on the Teensie. It is only blinking about once per second.

    I bought it here and believe set it up correctly.


    • what firmware do you use on your Teensy?

      APM MavLink to FrSky X8R S.Port converter


    • Try these values for your SR2 parameters:

      SR2_EXT_STAT = 10 
      SR2_EXTRA1 = 5
      SR2_EXTRA2 = 10
      SR2_EXTRA3 = 3
      SR2_PARAMS =0
      SR2_POSITION = 2 
      SR2_RAW_CTRL = 2
      SR2_RAW_SENS = 10
      SR2_RC_CHAN = 0

      (assuming you are using Telemetry 2 port for the Teensy.) 

      I posted discussion on this issue here:

      Serial 2 protocol needs to be set to 1 for mavlink. Teensy needs Mavlink data streams on input side. 

    • I started having some reliability problem with the same since 3.3 throughout rc2-rc5. Re-flashed tensy/taranis and fine-tuned params and it is ok again. Some further discussions are here.

      Tensy led messages are the following: (no of blinks)

      1 - No MAVLink data

      2 - No Telemetry packets

      3 - Missing SYS_STATUS data

      4 - Missing GPS data

      5 - Missing VFR_HUD data

      6 - Missing RAW_IMU data

      7 - Missing ATTITUDE data

      I believe only protocol Mavlink (1) will work - however SRx params needs to be set.

    • Hi, I have my Teensie on Pixhawk at Telem 1 without any problems. I miss only the dates of hdop, all the other dates comes correctly.

    • Wow somebody is making a killing on these lol nearly double the price of buying a 20 dollar Teensy and a few wires but anyway. You may have to enable the Telemetry on Serial 2 in advanced or tree view in mission planner.

      You may also need to click the button under "OSD" to enable telemetry to stream even if not detected.

      • Ah, well, there is a bit of code included. I don't care to spend hours constantly modifying lines of code when someone else did the work, "did" work well and looks good. If Droneshop wishes to continue selling their product, they need to support it. Peter King is a decent guy.

        Thanks for the info.

This reply was deleted.


DIY Robocars via Twitter
May 15
DIY Robocars via Twitter
May 14
DIY Robocars via Twitter
May 13
DIY Robocars via Twitter
RT @f1tenth: Say hi to our newest #F1TENTH creation for @ieee_ras_icra next week in Philly. It’s going to be huge! 😎 🔥 @AutowareFdn @PennEn…
May 13
DIY Robocars via Twitter
May 11
DIY Robocars via Twitter
May 8
DIY Robocars via Twitter
RT @SmallpixelCar: Noticed my car zigzagged in last run. It turned out to be the grass stuck in the wheel and made the odometry less accura…
May 8
DIY Robocars via Twitter
RT @SmallpixelCar: Test my car. RTK GPS worked great. Thanks @emlid for their support.
May 8
DIY Drones via Twitter
RT @chr1sa: @kane That's @diydrones circa 2009. Still have a box of those Canon cameras that we used to strap into planes, just like this.…
May 3
DIY Robocars via Twitter
RT @chr1sa: Our next @diyrobocars race is going to be outside at a real RC racetrack in Fremont on May 28. Fully autonomous racing, head-to…
Apr 30
DIY Robocars via Twitter
RT @f1tenth: Our Spring 2022 F1TENTH course @PennEngineers is coming to an end with a head-to-head race as a big finale. So proud of our st…
Apr 26
DIY Robocars via Twitter
RT @DanielChiaJH: I wrote a thing! Throughout the development of my @diyrobocars car I've been using @foxglovedev Studio to visualize and d…
Apr 23
DIY Robocars via Twitter
RT @SmallpixelCar: My new car for high speed. Low body, everything ( @NVIDIAEmbedded Jetson Xavier NX, @emlid RTK GPS, IMC) under the deck…
Apr 23
DIY Robocars via Twitter
Apr 21
DIY Robocars via Twitter
RT @f1tenth: F1TENTH Race training setup @PennEngineers for our upcoming ICRA2022 @ieee_ras_icra competition. @OpenRoboticsOrg @IndyAChalle…
Apr 21
DIY Robocars via Twitter
RT @fatcatFABLAB: Proud to be hosting a restarted DIY Robocars NYC Meetup April 26. Come by if you want to talk about and race self-driving…
Apr 17