Sending custom mavlink message from raspberry pi to pixhawk using pymavlink

#1

Hi,

i am trying to send a custom mavlink message from my companion raspberry pi to my pixhawk. In order to set this up on the pixhawk I followed the guide on the website (https://dev.px4.io/en/middleware/mavlink.html).

This is the custom mavlink message I want to send to the pixhawk from the pi: https://pastebin.com/6k5ySmyJ

After following the guide the code compiles. If I understand the guide correctly I can now send the custom message from my pi to the pixhawk and it will receive it and publish it to the new uORB topic.
So I only have to send the message over mavlink. Here is the problem i think since I don’t really know how to send custom messages with pymavlink. Right now I am using this code:

# open connection to pixhawk
mavs = mavutil.mavlink_connection("/dev/ttyS0", baud=921600)

# wait for the heartbeat message to find the system id
mavs.wait_heartbeat()

# send auv data
while(True):
        mavs.mav.command_long_send(mavs.target_system, mavs.target_component,
        command=213, 
        confirmation=0,
        param1=1,
        param2=1,
        param3=1,
        param4=1,
        param5=1,
        param6=1,
        param7=1)

The codes executes fine so the message is being send I think but it does not seem to reach the pixhawk. I wrote a simple app to publish the uORB topic on the pixhawk and nothing seems to arrive there.
Can someone help me with this? Is the problem that the mav.command_long_send() function can not be used for this? Do i need to extend the pymavlink library by my own function and if so how do I do this?

Thanks for your help