How to C# connect to Ouster Gemini MQTT output

C# implementation of an MQTT client that subscribes to topics published by Ouster
Gemini. The client connects to an MQTT broker, subscribes to the specified topic, and prints the received
messages.

System Requirements (tested on Ubuntu 22.04)

.NET SDK 8.0
M2Mqtt Library

Getting Started

Step 1: Install .NET SDK

Update the package index:

sudo apt update

Install the .NET SDK:

sudo apt install dotnet-sdk-8.0

Step 2: Create a New C# Project

Create a new directory for your project:

mkdir -p ~/mqtt_client
cd ~/mqtt_client

Initialize a new C# console project:

dotnet new console -n MQTTClient
cd MQTTClient

Step 3: Add the M2Mqtt Library

Install the M2Mqtt library via NuGet:

dotnet add package M2Mqtt

Step 4: Replace the Default Code

Open the Program.cs file:

nano Program.cs

Replace the contents with the following code:

using System;
using uPLibrary.Networking.M2Mqtt;
using uPLibrary.Networking.M2Mqtt.Messages;
class MQTTClient
{
    static string broker = "192.168.1.15";
    static int port = 1883;
    static string topic = "/ouster/detect/data";
    static string clientId = "subscribe-" + new Random().Next(0, 100);
    static void Main(string[] args)
    {
        MqttClient client = new MqttClient(broker, port, false, null,
        null, MqttSslProtocols.None);
        client.MqttMsgPublishReceived += (sender, e) =>
        {
            string message =
            System.Text.Encoding.UTF8.GetString(e.Message);
            Console.WriteLine($"Received `{message}` from `{e.Topic}`topic");
        };
        client.Connect(clientId);
        if (client.IsConnected)
        {
            Console.WriteLine("Connected to MQTT Broker!");
            client.Subscribe(new string[] { topic }, new byte[] {
MqttMsgBase.QOS_LEVEL_AT_LEAST_ONCE });
        }
        else
        {
            Console.WriteLine("Failed to connect to MQTT Broker.");
        }
        // Keep the application running to listen for messages
        Console.ReadLine();

    }
}

Save and close the file (CTRL + S, then Enter, and CTRL + X to exit).

Step 5: Build and Run the Application

Build the project:

dotnet build

Run the application:

dotnet run