How would one go about using Matlab to stop data acquisition at a certain threshold?

I'm working on a project involving taking in data, and I need to design a code which will stop the data collection once a certain threshold has been reached. I have a separate Python based program which I am using to take in the data, but I want to use Matlab in order to examine the data, while it is being acquired, and stop dats acquisition at a certain threshold. So to say, once data X reaches threshold Y, then warning Z will be displayed and data acquisition will be discontinued.

Answer 1

[TED MOSBY]

Hi Zachary,

As you have not shared your python code on how you are acquiring the data in python and using MATLAB for a real time communication with the python script. I can give a workaround using some basic assumptions as shown in the code below:

MATLAB Script to Monitor Data and Stop Acquisition at Threshold

dataFilePath = 'path_to_data_file.txt'; % Path to the data file being written by Python 
stopSignalPath = 'path_to_stop_signal.txt'; % Path to a stop signal file 
threshold = Y; % Define your threshold value Y 
checkInterval = 2; % Time in seconds between checks 
while true 
    % Read the latest data from the file 
    data = dlmread(dataFilePath, ','); 
    % Assuming the data of interest is in a specific column, e.g., first column 
    latestData = data(end, 1); % Get the latest piece of data 
    % Check if the latest data exceeds the threshold 
    if latestData >= threshold 
        % Display warning  
        warning('Threshold reached. Data acquisition will be stopped.'); 
        % Write a stop signal to a file (or another stop mechanism) 
        fid = fopen(stopSignalPath, 'w'); 
        fprintf(fid, '%s', 'stop'); 
        fclose(fid); 
        % Optionally, break the loop if no further processing is needed 
        break; 
    end 
    % Wait for a bit before checking again 
    pause(checkInterval); 
end 

Python Script

import time 
stopSignalPath = 'path_to_stop_signal.txt' 
while True: 
    # Your data acquisition logic here 
    # Check for the stop signal 
    try: 
        with open(stopSignalPath, 'r') as file: 
            signal = file.read().strip() 
            if signal == 'stop': 
                print("Stop signal received. Ending data acquisition.") 
                break 
    except FileNotFoundError: 
        # Handle the case where the MATLAB script hasn't created the file yet 
        pass 

As this just an example script, feel free to adjust things according to your requirements.

Hope this helps!