On Wed, Jan 29, 2025 at 6:34 AM Matteo Golin <matteo.go...@gmail.com> wrote:
> Hello again everyone, > > I was going through some of the NuttX documentation for UORB again since > InSpace is using it in our applications and > also to mock our sensors to see our system response in different scenarios > (we are planning to use a modified fakesensor > example). > > I noticed an intriguing application mentioned in the documentation that it > would be possible to create a UORB node that > subscribes to other sensor nodes and performs fusion/creates a new output. > The docs mention PX4's use of this and links > to this graph: https://docs.px4.io/main/en/middleware/uorb_graph.html > > Yes, you can subscribe sensor and read data from userspace by: orb_subscribe: https://github.com/apache/nuttx-apps/blob/master/system/uorb/uORB/uORB.h#L447 orb_copy: https://github.com/apache/nuttx-apps/blob/master/system/uorb/uORB/uORB.h#L495 Note: you need poll fd before orb_copy, or use orb_loop_init to assist you manage multiple data sources. and publish the fusion data by: orb_advertise: https://github.com/apache/nuttx-apps/blob/master/system/uorb/uORB/uORB.h#L284 orb_publish: https://github.com/apache/nuttx-apps/blob/master/system/uorb/uORB/uORB.h#L374 For our application, we would be doing things such as calculating altitude > from barometer data, or roll/pitch/yaw > measurements from IMU + magnetometer data. I am thinking that such a node > might become useful for other NuttX users, but > I'm not sure where in the source tree it would live (or if it belongs > there). It's not a sensor so I don't think it > would go in `drivers/sensors`, Yes, only the physical sensor should be put into drivers/sensors, all algo should be put to userspace. This capability come from usensor: https://github.com/apache/nuttx/blob/master/drivers/sensors/usensor.c. but I'm not too sure. My reasoning is that since a "barometer topic" under > UORB has a > standard interface, it would be possible to register a altitude fusion > node which pulls from any barometer node, > irregardless of the barometer type. Please check whether https://github.com/apache/nuttx-apps/tree/master/system/uorb/sensor has defined the topic you need. If not, it's easy to add the new topic by following the same style. > If the user needs to add more configuration to the barometer, they could > use > `orb_ioctl` commands to modify the sensor settings from their application > and these changes would bubble up to any > fusion nodes. > > What are your thoughts on this? Would something like this be beneficial > for NuttX? > > Yes, it's a good idea to share the algo to the community, but we need to find a common place for them. Here is the current layout: kernel driver: https://github.com/apache/nuttx/tree/master/drivers/sensors userspace framework and tools: https://github.com/apache/nuttx-apps/tree/master/system/uorb fusion algo(not use uorb): https://github.com/apache/nuttx-apps/tree/master/inertial/madgwick we may need to consolidate the source code in userspace into one place. -- > Matteo Golin >
