Observable UDP Socket

antokhio · July 22, 2025, 8:32pm

Hi, I’ve been trying to make RPLidar UDP version (S2E I think) work. And I’m not very happy with way I have to deal with something I never tough exist an “UDP Socket” you can track progress here: GitHub - antokhio/VL.Devices.RPLidar at feat/udp-lidar

So I’m looking for something like:

socket.OnRecive =+ ???
OnRecive.Where(packet => myPacket)…

I’m using .net Socket, anyone seen any examples or lib that does that?

joreg · July 23, 2025, 9:15am

UDPServer (Reactive) returns an Observable which should be what you’re looking for here.

antokhio · July 24, 2025, 8:52am

This was prolly the first node I checked on the way… Sadly for whatever reason it does not receive anything…

When I was playing with this on C#, I noticed that there are two ways to initialize socket, one with “Bind” for TCP/IP and another one with “Connect” if you would like to connect to socket (The lidar in this case is a Server). Seems connect is not exposed.

Also when I try ReciveFrom in c# I had to specify the EndPoint and it was kinda necessary, otherwise it did not receive anything… Seems like IO.Socket needs few buffs to make it usable in this case.

Guess back to study source, prolly need to patch it somewhere a bit…

joreg · July 24, 2025, 9:04am

are there any official specs regarding how to talk to the rplidar via udp? if you could share a link we’d not need to guess things here.

antokhio · July 24, 2025, 9:32am

gist.github.com

https://gist.github.com/antokhio/887089e7b584a3cb0df34469c24d68ee

RPLidarUDPSocket.cs

// based on https://github.com/vvvv/VL.StandardLibs/blob/3343499ace0997feb6227f9da1581badac37fc42/VL.CoreLib/src/IO/Socket/UdpSocket.cs#L9

using System.Net;
using System.Net.Sockets;
using VL.Core.Import;
using VL.Lib.Basics.Resources;
using NetSocket = System.Net.Sockets.Socket;
namespace VL.Devices.RPLidar
{
    [ProcessNode()]

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that seems to establish connection

that the PDF protocol https://download-en.slamtec.com/api/download/rplidar-s2e-protocol/1.0?lang=en

antokhio · July 25, 2025, 8:36am

@joreg so the code from above works decently and lidar connection is stable and working, I guess I’ll do PR on corelib to add UDPSocketClient to avoid extra C# code in the lidar repo, and then I can PR the lidar stuff

github.com/vvvv/VL.StandardLibs

Added udp socket client

main ← antokhio:feature/udp-socket-client

opened 08:35AM - 25 Jul 25 UTC

antokhio

+58 -0

# PR Details Added udp socket client ## Description Allows to connect t…o remote UDP Socket ## Related Issue https://forum.vvvv.org/t/observable-udp-socket/24484/3 ## Motivation and Context Could not connect to remote UDP Socket ## Types of changes - [ ] Docs change / refactoring / dependency upgrade - [ ] Bug fix (non-breaking change which fixes an issue) - [x] New feature (non-breaking change which adds functionality) - [ ] Breaking change (fix or feature that would cause existing functionality to change) ## Checklist - [ ] My change requires a change to the documentation

The updates to RPLidar UDP would be on same branch GitHub - antokhio/VL.Devices.RPLidar at feat/udp-lidar

antokhio · August 5, 2025, 10:54pm

@joreg a reminder…

joreg · August 6, 2025, 10:38am

it’s on the list but I’m afraid will take a bit more to review due to slow summer time

joreg · August 17, 2025, 4:49am

please see my answer in the PR.

independently: i’d anyway say that since VL.Devices.RPLidar’s underlying library includes the code for the serial connection, it should also contain the code for the udp connection.