Hi,
I keep working on my IOT application. I intend every picow to host a website to change global state for all nodes in my LAN. When a change is posted from a browser to any picow device, I want all the other LAN picow nodes to get updated. I was planning on doing direct server to server connections, but I am now trying to use multicasting. I know it is UDP, but plan on making sure everyone gets updated with a custom higher level protocol.
There are no github examples for using multicasting except using Freertos. The logical thing is to use the mdns or ntp as examples, but they are complicated! For my app I would like to avoid the extra complications with the OS I would like to use Poll or background mode, so I cannot use the unix like socket interface.
Surfing the lwip source code makes it seem like the ip level figures out the multicast stuff from the ip addresses used. It seems that is not quite correct. I have not figured out how to join a multicast group. And using tcpdump on a mint computer is obscure at best, especially for multicast groups.
So does anyone have a pointer to a multicast example app using poll or background for the pico? When I get it working I will publish a minimalish example
Thanks, Steve
I keep working on my IOT application. I intend every picow to host a website to change global state for all nodes in my LAN. When a change is posted from a browser to any picow device, I want all the other LAN picow nodes to get updated. I was planning on doing direct server to server connections, but I am now trying to use multicasting. I know it is UDP, but plan on making sure everyone gets updated with a custom higher level protocol.
There are no github examples for using multicasting except using Freertos. The logical thing is to use the mdns or ntp as examples, but they are complicated! For my app I would like to avoid the extra complications with the OS I would like to use Poll or background mode, so I cannot use the unix like socket interface.
Surfing the lwip source code makes it seem like the ip level figures out the multicast stuff from the ip addresses used. It seems that is not quite correct. I have not figured out how to join a multicast group. And using tcpdump on a mint computer is obscure at best, especially for multicast groups.
So does anyone have a pointer to a multicast example app using poll or background for the pico? When I get it working I will publish a minimalish example
Thanks, Steve
Statistics: Posted by nospamcalfee — Sun May 11, 2025 12:29 am