Add broadcasting

[knmcguire]

Crazyflie-link-cpp can do swarm broadcasting, so why not the link on the cflib!

This is a missing functionality in Crazyswarm2 that blocks the cflib from being a drop in replacement for the cpp backend: IMRCLab/crazyswarm2#423

[NageshEranki]

Hi, this is an enhancement I'm really interested in and would like to see cflib support broadcasting. I'd love to contribute but could really benefit from some pointers.

EDIT 1: I found this old Bitcraze forum thread that was quite informative. I can confirm that the example python script works. Is that post still a good starting point for development?

Thanks

[ArisMorgens]

Hello Nagesh!

It is so nice to hear that you are interested in contributing!
Swarm broadcasting is indeed not supported by the cflib and is only implemented in the firmware.

Our most recent use of broadcasting was for the decentralized brushless swarm demo. For that, we used a "hacky" solution where a non-flying Crazyflie is responsible to broadcast to all others.
You can find the source code for the demo in our crazyflie-firmware-experimental repository.
Let us know if you need any further help.

[NageshEranki]

Hi Aris,

Sorry for the delay in getting back to you. Thanks for the solution! There are no such things as 'hacky' solutions :) While it's a great starting point, I'm more interested in extending crazyflie-lib-python to do what crazyflie-link-cpp does.

Between my message on this thread and now, I used crazyflie-link-cpp directly to broadcast position feedback from mocap and position setpoints to 5 Crazyflies. Attached is an example script for the same.

I flash an app on the drone; I attached the C file for that too.

Do you think it is possible to directly program in python what crazyflie-link-cpp does?

app_broadcast_fixed_point.c.txt

broadcast_fixed_point_poses.py.txt

[ToveRumar]

Hi @NageshEranki!

This would definitely be interesting!
We definitely want this feature, however the cflib does not support it as of now.

I think its possible to do it, but you would need to implement the full chain in the cflib. Right now every connection in the cflib only connects to one Crazyflie. If you where to implement it I would suggest maybe creating a new way of setting up a link, or using a special address that would be the broadcast address.

This would be a feature somewhat on the bigger side to implement, but definitely fun and interesting!

Did this answer your question?

[NageshEranki]

Hi Tove!

Thanks a lot for the pointers! Let me see what I can do