How to Publish Simulink output into Websocket

I want to publish the simulink output into Webscket in JSON format. How can i do this? The Rasberry Pi websocket block does not work

[Prasanth Sunkara]

Hi Amish,

Could you please share more info on what you have tried with the Raspberry Pi block? Also, who did you conclude it did not work. Did you try any Simulink example related to web socket blocks?

[Amish Chavda]

Hi Prashant,

The Rasberry Pi block needs dedicated Rasberry Pi HW. I tried in Simulink with Matlab function block. But the JSOn encode and websocksts needs Matlab engine to run. .So it works only in Simulation. No C code possibility.

In the end i just switched to Python

Answer 1

[Aman]

Hi,

I understand that you have a Simulink model and want to publish its output to a WebSocket but are unable to do so, and the Raspberry Pi WebSocket block is also not able to do the task.

Without the actual error information, it is difficult to give an upfront explanation of why the Raspberry Pi WebSocket block failed to publish the signal.

Alternatively, you can create a function in MATLAB to publish the data received to a WebSocket; for this, you need to use the "webwrite" function that writes the content to the WebSocket. Once the function is developed, you can call it by using the "MATLAB Function" block in Simulink.

You can refer the below example code for reference.

function sendJSONDataToWebSocket(data)
% Convert data to JSON format
jsonData = jsonencode(data);
% Specify the WebSocket URL
webSocketURL = 'ws://your-websocket-url';
% Set the HTTP headers
headers = struct('Content-Type', 'application/json');
% Send the JSON data to the WebSocket server
webwrite(webSocketURL, jsonData, 'Headers', headers);
end

Please refer the following documentation to learn more about the “webwrite” method.

https://www.mathworks.com/help/matlab/ref/webwrite.html?s_tid=doc_ta

Also, to learn about “MATLAB Function” block of Simulink, please refer the following documentation.

https://www.mathworks.com/help/simulink/slref/matlabfunction.html

I hope it helps!

[Amish Chavda]

Webrite doesnt support Ws.

Is theer any other method

The 'ws' protocol specified in URL, 'ws://localhost:16016', is not supported. Specify the URL with the protocol 'http://' or 'https://'