Hi ismat,
You could use timer for more precise control of the LED.
However, for simple application, you can use pause() in Matlab (or Sleep() in C++,). There will be a small milli-seconds of the interval depends the code runtime. Matlab scripts works well for this.
You can store your led_value in this variable led_results. You can look at the example code below in Matlab:
led1 = 0; % initially the LED is off
t = 0; % initialize time to zero
dt = 1; % time step size in seconds
stop_time = 9; % stop time in seconds
led_time=3;
% preallocate array to store LED results
led_results = zeros(1, stop_time/led_time);
% loop until stop time is reached
while t < stop_time
% wait for 3 seconds
pause(led_time)
% turn LED on
led1 = 1;
led_results(floor(t/led_time)+1) = led1; % store LED result
% wait for 3 seconds
pause(led_time)
% turn LED off
led1 = 0;
led_results(floor(t/led_time)+2) = led1; % store LED result
% increment time
t = t + 2*led_time;
end
% display LED results
disp(led_results)
