This Python module provides functions to send and receive UDP messages in MATLAB (or directly in Python).

MATLAB functionality assumes you have MATLAB set up to run Python code. See: https://www.mathworks.com/help/matlab/call-python-libraries.html

In the examples below, replace my IP address (192.168.1.12) with your IP address.

Files:

• matlab_udp.py contains the module. No other files needed to use the module.
• udp_send.py is a Python script that uses the module to send a UDP message in Python or terminal command line.
• udp_rx.py is a Python script that uses the module to receive a UDP message in Python or terminal command line.

Use the module's send() function to send a message via UDP to a specified IP and port.

The function returns the number of bytes sent.

Example usage in MATLAB:

>> a = py.matlab_udp.send('192.168.1.12', 5005, 'Hello');

Example usage in Python:

>>> import matlab_udp
>>> matlab_udp.send('192.168.1.12', 5005, "Hello")

This message can be received in Linux using netcat to listen:

$ nc -kluv 5005
Listening on [0.0.0.0] (family 0, port 5005)
Hello

Use the module's receive() function to receive a message via UDP from a specified port.

The function will block until a UDP message is received.

The function returns the message, IP address of sender, and port of sender.

Example usage in MATLAB:

>> msg = py.matlab_udp.receive(5005);

Then, send a message from a Linux terminal using:

$ nc -u 192.168.1.12 5005
Hello

The msg variable contains the message:

>> msg
msg = 
      Python tuple with no properties.
    ('Hello\n', '192.168.1.12', 47185.0)
>> char(msg{1})
ans =
    'Hello
     '
>> char(msg{1}(1:end-1))
ans =
    'Hello'
>> char(msg{2})
ans =
    '192.168.1.12'
>> msg{3}
ans =
       47185    

Note that nc sends an end-of-line, so the message string has an end-of-line. This module's send() function does not send the end-of-line.

Example usage in Python:

>>> import matlab_udp
>>> matlab_udp.receive(5005)

Then, send a message using:

$ nc -u 192.168.1.12 5005
Hello

Python will show:

(u'Hello\n', '192.168.1.12', 47185.0)

To send a message via UDP from a Linux terminal using the matlab_udp module, use the udp_send.py script.

$ python udp_send.py 192.168.1.12 5005 "Hello"
Sent 5 UDP bytes to 192.168.1.12:5005  Hello

This message can be received in another Linux terminal using:

$ nc -kluv 5005
Listening on [0.0.0.0] (family 0, port 5005)
Hello

To receive a message via UDP from a Linux terminal using the matlab_udp module, use the udp_rx.py script.

$ python udp_rx.py 5005

Then, send a message from another Linux terminal using:

$ nc -u 192.168.1.12 5005
Hello

The terminal running udp_rx.py will show:

Received UDP from 192.168.1.12:47185 Hello