mavlink / libevents Goto Github PK

hey @bkueng

I am pondering over using the events to report the prearm status of the STorM32 gimbal controllers, but have some points I can't figure out and don't understand, but don't know where to ask for clarification, hence this issue here. I hope you find this appropriate.
(I read up as much of the available info as I could find, below, mavlink docs, PX4 docs).

The available docs mention specifically health and arming as use case, as well as it's not only for the autopilots but also components, and that events can be specific to an implementation. So, this makes me hopeful, but I don't yet get it.

The STorM32 gimbal controller represents a mavlink gimbal component, and I currently am using a device specific message https://github.com/mavlink/mavlink/blob/master/message_definitions/v1.0/storm32.xml#L560-L567, which I wonder if it can be replaced with device-specific events.

There are two questions however, spurred by comments in the docs

• "Each namespace has a name and an 8 bit component ID (typically matching the MAVLink component ID). Within a namespace, each event has a unique name and sub ID (24 bits). The event ID is the combined component ID with sub ID" (this repo)
• "from that name, a 24 bit event ID is derived using a hash function." (PX4 docs)
• "A UI should not display unkown groups." (this repo)

Obviously, the STorM32 controller would need to send the event with an ID. I don't understand how to decide on this ID. The docs imply that I somehow can create an implementation-specific ID, but I can't see how this possibly could work without having to register this ID with the mavlink project. I mean, to me it looks like it needs to be GUID.

Moreover, gimbals like any component can have whatever component ID they want, so how can there ever be a somewhat generically defined event, and be it only generic for all STorM32 gimbals? I.e., the "component ID" part of the ID spec does not make any sense to me, but just creates problems.

So, what ID shall I use for "my" STorM32 prearm event?

Second, how can device-specifi/implementation-specific events, which obviously will be in their own group, ever be of any use if a UI should not display unkown groups? Again, I conclude that it all only ever could work out if one registers the event with the mavlink project.

Many thx in advance.