Turning on and off leds with Arduino with parallel loops

Hi everyone,

I am trying to turn on and off leds randomly but independently. I think it might be doable with parallel loops, but I get an error saying "Arduino objects cannot be saved to disk, and will be skipped." Is it possible to do what I am trying?

a = arduino();

t1 = parfevalOnAll(backgroundPool, @f1, 1, a, 'D7')
t2 = parfevalOnAll(backgroundPool, @f1, 1, a, 'D4')

v1 = fetchOutputs(t1);
v2 = fetchOutputs(t2);
clear

function [tx, ty] = f1(a, pin)
tx = zeros(10, 1);
ty = zeros(10, 1);
for i = 1:10
    writeDigitalPin(a, pin, 1);
    x = rand(1);
    tx(i) = x;
    pause(x)

    writeDigitalPin(a, pin, 0);
    y = 2 * rand(1);
    ty(i) = y;
    pause(y)
end
end

Answer 1

[Taylor]

The issue you're encountering is related to the fact that arduino objects are not serializable and cannot be passed directly to parallel workers because they cannot be saved to disk. When using parallel processing in MATLAB, each worker operates in its own separate process, and objects like arduino cannot be directly shared across these processes.

If your goal is to toggle each LED randomly and independently you could try just creating the random order of pins and delay times before entering the loop, and then just loop through them. In the code below, you would just replace the display commands with your function to toggle the specified pin on/off.

pins = "D" + (1:10)

pins = 1x10 string array
    "D1"    "D2"    "D3"    "D4"    "D5"    "D6"    "D7"    "D8"    "D9"    "D10"

randIdx = randperm(length(pins));
pauseTimes = rand([1 10]);
for ii = randIdx
    disp(pins(ii))
    disp(pauseTimes(ii))
end

D7

    0.6864

D8

    0.2819

D3

    0.5752

D4

    0.8155

D1

    0.6598

D5

    0.4251

D2

    0.9067

D10

    0.1653

D9

    0.4702

D6

    0.8848

Answer 2

[MathWorks MATLAB Hardware Team]

Hi,

MATLAB Support Package for Arduino Hardware doesn't support parallel executions. Please feel free to refer following link for more info,

https://in.mathworks.com/help/matlab/supportpkg/getting-started-with-matlab-support-package-for-arduino-hardware.html

Thanks

MATLAB Hardware Team

MathWorks