How can I limit input into the command window?

I have written an experiment where once in a while I have to input some numbers (1 and 2) into the command window to make the experiment continue. I am currently doing this using the input() function. However, the participant also has access to an instrument which writes letters to matlab. I want to limit the characters I can write into the command window to only include the numbers, so that the instrument doesn't interfere with my input. Checking for the right input after its been given will not work, as the instrument can continuiously send letters, making it impossible for me to write in just my numbers.

I currently have these lines of code, where I manually input whether I want to continue or abort after each block of trials, after which my input is evaluated.

    while 1
            cont=input(sprintf("do you want to continue with block %g?  (1 for yes, 2 for no and abort):    ",wrun));
            %%% if you want to continue, go to next iteration (end while loop)
            if cont ==1
                break
                %%% if you want to abort, make stop variable (end while loop)
            elseif cont ==2
                stop=1;
                break
            end

Answer 1

[Star Strider]

I generally prefer to use the inputdlg fucntion, since it does not involve the Command Window.

If MATLAB is writing to the Command Window and that is causing problems using the input function, inputdlg could be a way to avoid that.

[Femke R]

Thanks for your reply! The problem is that the instrument the participant is holding writes letters to matlab in general (it is treated as a keyboard). So even in a pop-up window, the instrument could still write letters, interfering with the numbers I need to write. Is there a way with inputdlg to limit which keypresses actually make it into the window?

[Rik]

Then maybe you should consider a figure with a keypress function callback. That way you can forward the letters to anywhere you need, and you can catch the numbers for this loop.

[Star Strider]

My pleasure!

My answer is based on my understanding that MATLAB was writing to the Command Window and that was interfering with the input function. I have no idea what ‘the instrument’ is doing, or how to restrict its imputs to MATLAB, since I have no idea what it is or how it works.

The only other option I can suggest is questdlg since that requires clicking on a radio button for input. If there are a restricted number of possible inputs to it, that could potentially work. The listdlg function is another option to consider.

I obviously cannot test any of these, so this is my best guess.

[Femke R]

Questdlg solves my problem, thank you!

[Star Strider]

As always, my pleasure!