Broadcasting while connected to PC

[Novakasa]

Hi, I didn't find a definitive answer on this, is it possible to have a hub broadcast while it is connected to the PC?
I'm currently thinking about ways to scale the train layouts to more hubs than the bluetooth connection limit of about 7-8, and I'm currently envisioning broadcasting to be able to do that. Trains would still be connected to the PC, but stationary hubs controlling switches and level crossings could communicate with a "master hub" via broadcasting. The master hub then would also need to be connected to the PC.

An alternative would be to also have the PC be advertising while connected to the trains at the same time, though i'm imagining that to be kind of difficult since most bluetooth libraries don't seem to support both bluetooth as a "server" and "client" simultaneously (I'm currently looking at rust libraries mainly)

So, I guess my concrete questions would be:

• Can a pybricks hub broadcast while connected to a PC via the pybricks protocol
• Would a design like this allow me to push beyond the connection limit of around 7-8?
  • ~4-6 train hubs connected to PC
  • 1 master hub connected to PC while simultaneously broadcasting (could maybe also be a train hub)
  • ~5-10 stationary layout hubs not connected to PC, only listening to broadcast data

[dlech]

It depends on the hub. On BOOST move hub, it doesn't work at all, IIRC. On city hub and technic hub, it kind of works, but many packets are dropped/latency is increased. Prime/Inventor/Essential hubs will work the best.

[dlech]

As long as it is not a Mac, a PC should work. I think there was some discussion about that in the last 6 months or so.

[Novakasa]

I guess as a follow-up on that, when a hub runs a program, it stops advertising, right (unless it broadcasts)? So the amount of bluetooth traffic is minimized if only one hub is broadcasting

[dlech]

Correct.

[laurensvalk]

Technic/City Hub is actually pretty good at broadcasting while connected. It's mainly observing while connected that isn't great.

So in applications like these, if you keep the listening hub program as simple as possible so that it almost never needs changes, then continuously reprogramming and debugging the sender program which has all the logic is still pretty convenient.

[Novakasa]

Awesome, that sounds very promising! I will test this scenario first before investigating PC-side/raspberry-pi broadcasting