running uxrce_client with voxl2-px4

Kyuhyong You

Hello,
I just wondering if volx2-px4 can run uxrce_dds_client as described here.
https://docs.px4.io/main/en/middleware/uxrce_dds.html

I was able to build install ros2 on voxl2 and uxrce_dds_agent and runs ok with external FC.

I also found voxl-px4 runs with v1.14.0 version

pxh> ver mcu
UNKNOWN MCU
pxh> ver hw
HW arch: MODALAI_VOXL2
pxh> ver all
HW arch: MODALAI_VOXL2
PX4 git-hash: 
PX4 version: 1.14.0 0 (17694720)
Vendor version: 2.0.34 0 (33563136)
OS: Linux
OS version: Release 4.19.125 (68386303)
Build datetime: Jun  7 2023 14:33:27
Build uri: localhost
Build variant: default
Toolchain: GNU GCC, 7.5.0
PX4GUID: 
UNKNOWN MCU

Is it possible to run dds client?

Zachary Lowell 0

@Kyuhyong-You the voxl2 on sdk 1.1.0 runs the dds_client out the gate. You can see here in the executable of PX4 that we spin up the dds client:

https://github.com/modalai/px4-firmware/blob/557d402e84e0a3ea122a0383270ff680d920bb7e/boards/modalai/voxl2/target/voxl-px4-start#L213

# Start microdds_client for ros2 offboard messages from agent over localhost microdds_client start -t udp -h 127.0.0.1 -p 8888

In order to communicate - make sure you have voxl-microdds-agent installed via apt-get as well as configured. Then you should be able to communicate over the bridge:

Here are the instructions: https://docs.modalai.com/ros2-installation-voxl2/

Kyuhyong You

@Zachary-Lowell-0
Thanks for your comment!

So it means px4 on voxl2 is running microdds_client which is not compatible with uxrce_dds_cleint on the PX4 release/1.14.0
And the microdds_client will start automatically when px4 on voxl2 service is up and running?

Zachary Lowell 0

Sure thing @Kyuhyong-You . That is correct - currently the voxl2 runs the microdds client instead of the uxrce dds client on 1.14.0 stable. The microdds client starts automatically on the voxl2 when px4 is instantiated - if not, feel free to build PX4 yourself and flash it on the board via the instructions here:

https://docs.modalai.com/voxl-px4-dev-build-guide/

There is also another service available on SDK 1.1 (https://docs.modalai.com/sdk-1.1-release-notes/) called microdds-agent which spins up the agent to listen to localhost port 8888 and allow for comms similar to mavsdk.

https://docs.modalai.com/ros2-installation-voxl2/