Issue with connecting gimbal to Pixhawk

PX4 Autopilot
1

I have a 3 axis gimbal with a camera payload attached. This gimbal responds correctly to mavlink messages (in the gimbal v1 protocol) when sent through a serial connection to a uart port.

But I am unable to make it work when I connect it to a pixhawk (6c) board. I connected the uart port of the gimbal to the telem2 of the board and am sending messages over a GCS. I’ve set the required parameters in PX4 to make it connect through the telem2 port according to this link. I tried debugging px4 and it is correctly handling the messages I am sending but I don’t understand how exactly the communication through the telem ports happens. As far as I can tell px4 handles the DO_MOUNT_CONTROL messages by transporting them through gimbal_v1_command uorb topic and outputs another DO_MOUNT_CONTROL message and it handles the SET_CAMERA_ZOOM message by converting it into actuator outputs in mavlink_receiver.cpp. But I don’t understand how any of this is supposed to translate to the commands being sent through the telem port.

If someone could help me understand how communication through the telem ports is handled or point out something I’m missing, that would be appreciated.

2

What gimbal controller are you using? I’m in about the same place with a non-nt storm32. I’ll update if I get it working or find anything else helpful.

Edit: to check serial/mav parameters I set system id to 1 and component id to 154 on the gimbal controller and was getting heartbeats on my ground station.

3

Just wanted to update that I have got mine working. It turns out Storm32 only works with px4 if you use the NT firmware. I think syntax has changed since the i2c firmware was written and it hasn’t been updated (no source code available unfortunately). The only place I could find to get an nt imu was ensys.lt
If you’re using alexmos/basecam, the manual looks like it’s only using ardupilot dialect.
I got my storm32 working using the same parameters as the instructions you linked with gimbal protocol v1.
Also I am using pixhawk 6c and latest stable px4 (1.13.2).

4

One more thing: to make sure all your serial/mavlink settings are correct set MAV_x_FORWARD to 1 and check your mavlink inspector in qgroundcontrol for a heartbeat.