PX4 Dev Call: April 07, 2021

April 07, 2021

Join us


  • Community Q&A
  • Roadmap
  • High priority queue
  • Release
  • In-Depth discussions


The 1.12 release is currently in beta testing.

There will be another incremental beta release after the PWM configuration for certain boards is fixed.

The release should be tested with QGC daily

Community Q&A

Crazyflie optical flow

Goncalo Antasio
is looking into getting the Crazyflie working with optical flow. He’s debugging with PX4_INFOs and checking ekf2 but doesn’t get a valid local position. First thing to check is if there’s optical flow data coming in. Please double check following documentation on the optical flow sensor that is on the Crazyflie: Optical Flow | PX4 User Guide PMW3901-Based Flow Sensors | PX4 User Guide especially verify that SENS_EN_PMW3901 is enabled and you get horizontal flow data. It’s independent of the distance sensor and its data.

Dodecarotor not properly loading the mixer

Strobino and AM
try to set up a Dodecacopter using a pixhawk 4. The IO mixer seems to be loaded correctly but the all-stock fmu mixer fails to load for an unknown reason. They get the expected output on the main outputs but no reaction on the aux outputs. Please open an issue with the details and a log from boot and we’re able to reproduce and load the same mixer to find the issue. It sounds like a broken airframe configuration. And please share a video when the vehicle is flying.

Sidenote: Mixer feedback is per mixer so as long as the mixers spread over IO and FMU are symmetric it makes sense but as soon as the FMU mixer doesn’t cover the necessary feedback anymore the response to limits will be assymetric.

In-Depth discussions

Convention on code base file names


  • Name the file after the only class that it contains for simplicity.
  • Name module folders and commands lower case snake case because we already use that from the beginning.
  • MAVLink stream definition files are all capital to be consistent with the MAVLink message naming.
    The goal is to have MAVLink generator handle more of the stream definition such that it’s only about the message interpretation with less error-prone boilerplate in the stream definitions.

Suggestion by @dagar to take google code style, change it to tabs for indentation and enforce it through clang-format. For a smooth transition just on new changes. That strategy worked before.
We have a clone of the style guide. Let’s adjust what’s necessary GitHub - PX4/styleguide: Style guides for PX4 source projects

Convention uORB topic names

  • the vehicle prefix doesn’t help
  • the sensor prefix is really helpful
  • we need to make sure the message defintions scale for support of a lot of messages for different use cases while not paying resources for unused messages
  • likely we require name spaces for messages
  • review of existing messages, don’t change them unnecessarily but any changes have to be acceptable


Discussion based on board: Roadmap · GitHub

High priority queue

Discussion based on board: High-Priority Queue · GitHub

If you have any feedback or corrections please comment on this post.