two while loops running at same time

while ~stop
 % Read current voltage value
x = readVoltage(a,'A0');
 % Get current time
 t = datetime('now') - startTime;
 % Add points to animation
 addpoints(h,datenum(t),x)
 % Update axes
 ax.XLim = datenum([t-seconds(15) t]);
 datetick('x','keeplimits')
 drawnow
 % Check stop condition (check the button on D6)
 stop = readDigitalPin(a,'D6');
end

while x>=2.9
if x>=3.3
    disp('signal recevied soil is dry time to water')
  writeDigitalPin(a,'D2',1);pause(5);writeDigitalPin(a,'D2',0);   
 x=x-0.5;
 elseif x>=2.9
   disp('signal received soil is wet but not wet enough time to water')
    writeDigitalPin(a,'D2',1);pause(5);writeDigitalPin(a,'D2',0); 
    x=x-0.5;
   
end
pause(20)
end 

I have these 2 while loops i want to run them at the same time independent of eachother how would i do that the first while loop is to graph an animated line of a moisture sensors values the second is to check the value of a moisture sensor

Answer 1

[Les Beckham]

You can't code them as separate loops and have them run "at the same time". Depending on how you want the timing to work, you should do something like this using only one loop (assuming you want to check your moisture sensor and update your plot every twenty seconds and stop the loop completely on the "stop condition"):

while 1 
    % Read current voltage value
    x = readVoltage(a,'A0');
    
    % Get current time
    t = datetime('now') - startTime;
    
    % Add points to animation
    addpoints(h,datenum(t),x)
    
    % Update axes
    ax.XLim = datenum([t-seconds(15) t]);
    datetick('x','keeplimits')
    drawnow
    
    % Check stop condition (check the button on D6)
    stop = readDigitalPin(a,'D6');
    if stop
        break; % break out of the loop
    end
    
    if x>=3.3
        disp('signal recevied soil is dry - time to water')
        writeDigitalPin(a,'D2',1);pause(5);writeDigitalPin(a,'D2',0);   
        x = x-0.5; % << why are you doing this?
    elseif x>=2.9
        disp('signal received soil is wet but not wet enough - time to water')
        writeDigitalPin(a,'D2',1);pause(5);writeDigitalPin(a,'D2',0); 
        x=x-0.5; % << why are you doing this?
    end
    
    pause(20)
    
end

I don't know why you have the x=x-0.5; lines. If you want the plot to reflect that offset, move the if/else block above the addpoints line or just subtract off the offset when you read the analog input instead.

[Walter Roberson]

You can't code them as separate loops and have them run "at the same time".

You can (see my Answer)... it just might not be a good idea.

[Les Beckham]

Good point, Walter.

I should have qualified that with "(unless you have the Parallel Computing Toolbox and are willing to make your code much more complicated)".

[Walter Roberson]

@Les Beckham

Well, background pool exists these days. Using it (or Parallel Computing Toolbox) is probably not a good design, but it could be done.

Answer 2

[Walter Roberson]

In order to run two loops independently of each other, you will need to use one of:

• parfeval and backgroundPool -- part of basic MATLAB; or
• parpool and parfeval or spmd or parfor -- Parallel Computing Toolbox

The loops will not be able to communicate directly with each other unless you use spmd. There are things you can do with parallel.pool.DataQueue to have the controlling thread relay data between workers. Also, you would need to test whether the arduino object gets shared between the workers (it might not.)