PX4 Community Q&A: August 02, 2023

August 02, 2023

Join us


  • Community Announcement
  • Community Q&A
  • General Discussions

:loudspeaker: Community Announcement

A.1 : PX4 Dev Summit CFP results announced next monday

A.2: PX4 v1.14-RC1 is out for beta testing!

Check out the release notes here:

:people_holding_hands: Community Q&A (No deep technical discussions)

:exclamation: Guideline for asking a Question

  1. Specify what you are trying to achieve
  2. Specify what environment / platform you are using
  3. Prepare a Link or Document to help understand if possible
  4. First, ask the question on Discord or create a Github Issue!
  5. If you take over 5 minutes for the question, please continue in Discord or a Github Issue.

Q.1 : About ORB ID - Toton

What happens when we reach the end range (255) of ORB ID?

Currently in this PR: [WIP] ROS 2: Library with dynamic modes API by bkueng · Pull Request #20707 · PX4/PX4-Autopilot · GitHub, we have overflow of ORB ID enums.

Answer: We can switch to uint16_t for uORB ID, but need to check if the performance degrades - Daniel

Note, there’s also some PR that tried to address this: U orb msg limit by hskrieg · Pull Request #20637 · PX4/PX4-Autopilot · GitHub

Q.2: Boat support in PX4 - slgrobotics

Lawnmower application was good, especially yaw rate controller. When would we get this in main branch? It seems very valuable.

The changes make sense, we should have brought it in as experimental feature. Need to check the merge conflicts.

Will bring this up in next week’s maintainers call and likely merge it.

:thinking: General Discussions

D.1 : CI depreceated set-output PR - farhang

Would be better to have minimal changes and only change the set-output part, and keep the whitechange / formatting PR separately.

D.2 : Remote ID PR update - Andrew

John is making progress on:

working with emergency status. This could be its own PR separate from 21647?

Discussion (also on discord):

  • Right now, the BASIC_ID can be tampered easily, and is not ‘protected’, this needs to be improved
  • EMERGENCY button in QGC currently doesn’t affect the status of Open Drone ID to emergency. Sending some kind of MAVLink command would be sensible


  • We should take care of added uORB topics, and MAVLink default streaming changes
  • Probably we should rely on ‘Mavlink Forwarding’, instead of having to go through uORB.
  • Stripping it down and making just the essentials stay for the uORB would be better.
  • Does ‘ARM STATUS’ streaming out depend on the incoming data?
  • Dronecode is interested in funding the development, so contact Ramon if you are interested!
  • Will have a dedicated Remote ID discussion next week Thursday - Andrew, Daniel.

Example CubeID to purchase: Cube ID | CubePilot – IR-LOCK

D.3: High RAM usage issue - Andrew

High ram usage on main with an older board:

  • With the ARK GPS, using UAVCAN
  • On v1.13, the RAM usage seems normal and UAVCAN seems to work fine


  • Alex: Did unnecessary UAVCAN topics disabled in the build part?
  • Which MAVLink streams are enabled?

D.4: MATEK H743-Mini configuration errors

  • The Board ID in firmware.prototype and defconfig in nsh doesn’t match up, so .px4 binary can’t be uploaded
  • After flashing the bootloader, Vendor ID and board ID shows up as “Holybro Durandal v1”, but then after flashing the .px4 binary, next time in QGC it shows up as Pixhawk V6U, how can this bootloader change?

Also the sensor rotation was wrong, etc. Will create a specific issue for this for more detail.

Related PR: boards/matek/h743: consolidate and fix h743 variants by dagar · Pull Request #20726 · PX4/PX4-Autopilot · GitHub

It’s especially tricky because we can’t automatically ‘detect’ which variant it is in the board. Also, not having to set new bootloader for PX4 purposes, and allowing to flash straight out of the package would be a great customer experience.

There’s a company wanting to have one of their new H743 ii13 based board supported in PX4

Matek H743 related issue has been posted here: