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!

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      • Lidar lite v2 is only 115.00.

        It would be nice to have the option use the installed sonar or lidar, either way OF is really neat feature.
        • I live outside their country, and shipment to my place is unusually high.

          I agree, having such option would be great.

          Tried to calibrate OF, but it seems without lidar flowX/Y and bodyX/Y are poorly correlated, scaling will not make them match (bodyX/Y and GyrX/Y do match).
    • I would say I am right there with you, but you have clearly thought this through more deeply than I have. I am getting ready to mount a px4flow but have not entirely wrap my mind around when OF works and if by using it I loose functionality some where else.

      I am interested in the answers to your questions also!

      Looking forward to an icon in mission planned to enable PX4Flow as a near plug and play option, with a calibration sequence similar to setting the Acc or compass.

      All is good time I am sure.
  • It's normal that I start autotune with


    and after autotune I have





    • Yes, these parameters are tuned on autotune routine. How are your copter flying with them?

      • I'm satisfied but just after second autotune The first wasn't good  (autotune>save>autotune>save)

        I have large x8  8 kg 

        • This procedure was recommended a few times. The autotune takes the currrent parameters as the starting point, thus , doing it two times would make the parameters more refined.

          If they are OK, with no wobbles, enjoy it!

  • Hi!

    I tried to use battery_voltage2 and current2, readings get to Pixhawk but scaled wrong?
    I received 15355V, tried to scale it to 15,3V but then I only get 15V. Using a standard power module connected to ADC 3.3V.

    Want to use 2 batteries in parallell and monitor each via separate power modules?

    Great job with the new version....


    • Developer


      I've never tried to monitor two batteries but it should work if you make most of the BATT2_ parameters the same as the equivalent BATT_ parameters.  We don't us the measurements from the second battery monitor for anything (i.e. battery failsafe) but I think you should be able to see the values in the Mission Planner (or other GCS perhaps) as "battery_voltage2", etc.

      • Randy,
        You are right I can see some values in MP but as I wrote I cant scale them correct without loosing the decimals?

        My settings for batt2:
        BATT2_MONITOR -> 4        (Analog Voltage and Current)
        BATT2_VOLT_PIN-> 13       (in MP A12 not sure if this is right since it is numbered 13 in the Picture in wiki)?
        BATT2_CURR_PIN-> 14      (in MP A13 not sure if this is right since it is numbered 14 in the picture in wiki)?

        And I have only connected pin 3,4 and 6 from Power module, and they are connected to ADC 3.3V on pin 2,4 and 5 and in that order.

        It is a quite Heavy X8 so I was thinking i might go over 60A if I run them via one Power module, and as I was having one spare, so why not try it this way?

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