Is it possible to use uORB directly in a voxl module?
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Hi ModalAI devs,
I'm wondering if it's possible to subscribe to a uORB topic in a voxl module. I want to subscribe to the barometer sensor and there isn't an MPA server for this.
The reason I ask is that when using the voxl-cross docker container I'm unsure which dependency is required to install to get access to the uORB headers etc.
Thanks,
Dan
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Hi Dan,
You can directly subscribe to the mavlink output using the
mavlink_to_px4pipe and check for messages of typeMAVLINK_MSG_ID_ALTITUDEto receive barometer updates in an MPA server.See here for a code example.
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Hi Matt,
Thanks for the quick reply and thanks for the example that's super useful.
Just to clarify what you're saying. From my understanding when I do
uorb topthe topic namesensor_barois available and I can callpx4-listener sensor_baroto get an update from what I believe to be a uorb message? Are you saying that there are mavlink messages also published that will give me the same information and I can use something similar to your example to then create a barometer MPA server?
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@Dan There is no uorb to pipe bridge so not really possible. But you can run the system command px4-listener and parse the output of it. Or if what you really need is something in a Mavlink message then you can go the route Matt suggested.
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There is a mavlink message you can parse for barometer data, that is the code example I sent above. In that file as well, there is an example of calling px4-listener programmatically and parsing its output - see here
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No problem. I was wondering if I could do that bridging myself by subscribing to the uORB topic
sensor_baroand then publishing onto a barometer MPA server but wasn't sure if it was possibly to subscribe to uORB topics in the voxl SDK.Thanks for the clarification. I'll take a look at the px4-listener parsing too.
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Apologies. Final question for now. Who is the producer of the mavlink message for the barometer data?
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The PX4 flight control software
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Thanks Chad.
