Record real-time EMG signal and Plot it.

Created this code :

%% Raw sEMG Signal Measuring with Precise Timing and X-Axis in Milliseconds
clc; 
clear; 
close all;
% Parameters
sampling_frequency = 1000;  % Sampling frequency in Hz (1 kHz)
duration = 60;              % Duration of signal acquisition in seconds
num_samples = sampling_frequency * duration;  % Total number of samples
% Swallow timer setup
swallow_interval = 10;  % Swallow every 10 seconds
next_swallow_time = swallow_interval;  % Initial swallow time
% Initialize variables
x = zeros(num_samples, 1);  % Array to store raw voltage data
time_ms = (0:num_samples-1) / sampling_frequency * 1000;  % Time array for x-axis in milliseconds
% Connect to Arduino with higher baud rate (115200)
a = arduino('COM8', 'Uno', 'BaudRate', 115200);  % Replace 'COMx' with your port
% Start acquisition and timing
start_time = tic;  % Start the overall timer
% Start loop to acquire signal
for i = 1:num_samples
    % Read voltage from analog pin A0
    raw_voltage = readVoltage(a, 'A0');
    
    % Store the raw voltage in the array
    x(i) = raw_voltage;
    
    % Calculate elapsed time
    elapsed_time = toc(start_time);
    % Swallow notification logic
    if elapsed_time >= next_swallow_time
        disp(['Time to swallow at t = ', num2str(next_swallow_time), ' seconds']);
        next_swallow_time = next_swallow_time + swallow_interval;  % Set next swallow time
        
        % Optional: Play a sound or beep for notification
        beep;  % Beep sound (you can adjust with 'sound' for different notifications)
    end
    % Stop acquisition after 60 seconds
    if elapsed_time >= duration
        disp('Acquisition complete. Plotting the signal...');
        break;  % Exit the loop once 60 seconds have passed
    end
    
    % Measure how long this iteration took
    iteration_time = toc(start_time) - elapsed_time;
    % Compensate for any delay in the loop to keep the sampling frequency consistent
    if iteration_time < (1 / sampling_frequency)
        pause((1 / sampling_frequency) - iteration_time);  % Adjust to match the sampling rate
    end
end
% Cleanup: Clear Arduino object when done
clear a;
% Plot the raw sEMG signal after acquisition (in milliseconds)
figure('Name', 'Raw sEMG Signal After Acquisition');
plot(time_ms(1:i), x(1:i));  % Only plot up to the last acquired sample
grid on;
title('Raw sEMG Signal After Acquisition');
xlabel('Time (ms)');
ylabel('Voltage (V)');
xlim([0, duration * 1000]);  % Adjust x-axis to show time in milliseconds
ylim([0, 5]);  % Adjust based on your expected voltage range

What I want to achieve is that i record every 10 second a muscle contraction and after 60 seconds I plot the signal. The problem is that it plots the whole signal before the first 10 second. I tried the first time to do it real time like recording and plotting the signal in real time, but the seconds were not right.The x-axis was every 0.5 seconds but the recording lasted much longer. What is the problem here I don't understand what I really need to fix. Maybe it;s the loop that takes time or the readVoltage function of the MATLAB, but how do I coordinate both of the times, the real time recording and the one plotting?