Sending live data readings from Raspberry Pi to laptop

Question

I have a simple Python code that takes readings from a temperature sensor. I wish to send these readings (each time one is recorded in the code's while loop) to my laptop so the values can be used in real time in an application I have created on my laptop using Visual C#.

Therefore, I would like to be able to add code into my existing Python code that instead of simply printing the sensor readings on the Pi, sends the values to my laptop in a way that can be read by a C# app.

I don't have wireless internet on the Pi, so I intend to send the data via a cable such as an Ethernet cable.

Any advice on how I could achieve this would be very appreciated, thanks.

Answer 1

You can use UDP fairly easily in both languages. Something like this on the Pi sets up sending packets:

import socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
message = "data you want to send"
sock.sendto(message, ("dns.or.ip.of.server", pick_a_port_number))

On the C# side it's a little bit more complex, but there's an example here, which I'll reproduce modified below:

using System;
using System.Net;
using System.Net.Sockets;
using System.Text;

public class UdpSrvrSample
{
   public static void Main()
   {
      byte[] data = new byte[1024];
      IPEndPoint ipep = new IPEndPoint(IPAddress.Any, pick_a_port_number);
      UdpClient newsock = new UdpClient(ipep);

      Console.WriteLine("Waiting for a client...");

      IPEndPoint sender = new IPEndPoint(IPAddress.Any, 0);

      data = newsock.Receive(ref sender);

      Console.WriteLine("Message received from {0}:", sender.ToString());
      Console.WriteLine(Encoding.ASCII.GetString(data, 0, data.Length)); // this will be "data you want to send"
   }
}

This page might also be useful.

Answer 2

I would like to be able to add code into my existing Python code that instead of simply printing the sensor readings on the Pi, sends the values to my laptop in a way that can be read by a C# app.

You want to use a use a TCP server/client model. Either end can be the server, the other is the client; the client connects to the server and establishes a connection, then information can be sent back and forth. Skeleton code for a basic client or server is probably only a dozen or so lines in python. Start by developing an echo server -- something that simply sends back the same message it is sent -- and then work from there.

You will get better help with this on a dedicated python or C# forum -- nothing about the task is specific to the pi. You should first look around for TCP networking tutorials involving either language and work through those. This way you can save yourself some time by coming to the table with specific questions and code demonstrating what you have tried/what problems you are having.

Answer 3

Using a Samba Server on your Raspberry Pi you could share a directory over the network. By putting your files in that directory you will have access to them from your laptop. By doing this you don't have to edit any code, more than changing what directory the Python program should write to.

Here you can read more about how to set up a Samba server and share folders.

Answer 4

As an alternate, post your readings to a web service, so your laptop need not be on to collect the information. You can fetch the readings on demand from your laptop or any other connected machine.Or

As per @goldilocks answer, this is not specific to pi so much as it is a general computing / programming question.