Question: How to test that mavlink works?

[phuesler]

Hi,

Thank you for creating and contributing to this useful project.

I'm struggling to understand the flow of data and hope that you can shed some light on it. Where can I test that I can start/top etc. the camera through mavlink commands? I was hoping this would work with QGrouncControl.

As I understand it, there are 4 components involved:

• A drone running a flight controller that speaks Mavlink. Or a sitl like ArduPilot sim_vehicle.py
• mavproxy
• mavlink-camera-manager
• A GCS like QGroundControl

Which components are connected together? I assumed that QGroundControl and mavlink-camera-manager, there is no need to involve the flight controller. But I'm starting to think that his is wrong. Because I can't get it to work:

I followed the example in the Readme and issued the following commands:

./Tools/autotest/sim_vehicle.py -v ArduCopter

./mavlink-camera-manager-linux-desktop --verbose --mavlink-system-id 1 --mavlink tcpout:0.0.0.0:5760

./QGroundControl.AppImage

I then changed the QGroundControl Application settings to listen on port 5600 for a UDP stream. Once configured in the UI of mavlink-camera-manager, the video shows up in QGroundControl.

When I check the output of mavlink-camera-manager, it doesn't say anything about a successful mavlink connection. It is outputting the same debug message about mavlink HEARTBEAT, regardless of weather QGroundControl is running or not.

2024-10-22T10:47:17.984371Z DEBUG sender_loop: src/lib/mavlink/manager.rs:175: Message sent: MavHeader { system_id: 1, component_id: 100, sequence: 0 }, HEARTBEAT(HEARTBEAT_DATA { custom_mode: 0, mavtype: MAV_TYPE_CAMERA, autopilot: MAV_AUTOPILOT_INVALID, base_mode: (empty), system_status: MAV_STATE_STANDBY, mavlink_version: 3 })

What am I missing here?

[joaoantoniocardoso]

Hi @phuesler,

Yeah, the exactly thing you are missing is to ask for mavproxy for an exclusive endpoint for mavlink camera manager.

./Tools/autotest/sim_vehicle.py -v ArduCopter --mavproxy-args --out=tcpin:0.0.0.0:5777

(note that here I'm using 0.0.0.0, which will allow incoming connections from any network. Feel free to use anything more restrictive, like 127.0.0.1)

and then:

./mavlink-camera-manager-linux-desktop --verbose --mavlink-system-id 1 --mavlink tcpout:127.0.0.1:5777

(note that I'm using 127.0.0.1 here because I'm assuming they are both running in the same machine)

I hope this helps, thanks!

[joaoantoniocardoso]

Oh, just to be clear:

• The "master" 5760 TCP is the communication between the mavproxy and the autopilot.
• The UDP 14550 is the default for GCS.
• so we need an extra endpoint for MCM (5777 TCP, for example)

[phuesler]

Thanks for your quick reply and for taking the time.

Unfortunately I see still the same behavior, issuing the above commands.

• mavlink-camera-manager is sending mavlink messages to mavproxy who sends it to the autopilot?
• mavlink-camera-manager is broadcasting its mavlink heartbeats announcing its camera?
• Does QGroundControl send the camera related messages to ArduPilot and not mavlink-camera-manager directly?
• What is the expected behavior in QGroundControl when it 'works'?

If it helps, I see this in the SITL console:

COMMAND_ACK: REQUEST_CAMERA_INFORMATION: UNSUPPORTED