Creating Countdown timer in Matlab App

Hi all,

I am trying to create a countdown timer in matlab. The user will press a button and that time will start to decrease. I have used an edit field text for the timer display. I am able to get the starting time displayed on the display, but am really struggling (i actually have no idea - even though I tried searching around) to determine how the 'countdown' works in Matlab. I have the following code:

properties (Access = private)
        timerLeft = 0; % Description
        end
        

and then:

        function BeginButtonPushed(app, event)
            
        end
        
        function FunctionalityTest10sButtonPushed(app, event)
            timerVal = 10;
            app.timerLeft = timerVal;
            app.timerCountdown.Value = '00:00:10';
        end

All help is really appriciated.

Answer 1

[Image Analyst]

See attached demo. It's in GUIDE but you can click the link/button to convert it to App Designer.

[Kanwartej Singh]

Hey, firstly thanks for this, however, I do not understand what it means by clicking on the button to convert it to App Designer? I clicked both of the links you attached yet got an error messaage.

[Image Analyst]

Right click in your browser and them download those files to your local drive. Then open guide

>> guide

When guide opens up, open up gostop.fig.

At the bottom there will be a banner asking if you want to convert the code to App Designer. Click that.

[Kanwartej Singh]

Hey, thanks for this. I got the 'timer' bit working with the pause command. However, what I don't know is how to get the display of hours, minutes and seconds in the format 00:00:00. I would be able to do it with just seconds with if statements and num2str but I have no clue on the minutes and hours bit aswell, and decreasing minutes as seconds go 00 etc. Could you help me with that. My current code is as follows:

    function BeginButtonPushed(app, event)
            message = '';
            i = 1;
            while i < app.timerLeft
                app.timerLeft = app.timerLeft - 1;
                pause(1);
                fprintf(num2str(app.timerLeft));
            end
        end

        % Button pushed function: TutorFunctionalityTest10sButton
        function TutorFunctionalityTest10sButtonPushed(app, event)
            timerVal = 10;
            app.timerLeft = timerVal;
            app.timerCountdown.Value = '00:00:10';
        end
    end

[Image Analyst]

Examples:

dt = datestr(now, "HH:mm:ss")

dt = '13:04:54'

t = datetime('now','TimeZone','local','Format','d-MMM-y HH:mm:ss Z')

t = datetime
   23-Apr-2022 13:34:55 +0000

t1 = datetime(2022,4,23,9,034,06, 'Format','HH:mm:ss')

t1 = datetime
   09:34:06

[Kanwartej Singh]

Hey,

So I went about this in a similar but different manner using the duration command(I bevlieve it is similar but is only for limited time segments, which is what I need). What I did was:

function BeginButtonPushed(app, event)
            for i = 1:length(app.strD)
                app.timerCountdown.Value = app.strD(i);
                pause(1);
            end
        end

        % Button pushed function: TutorFunctionalityTest10sButton
        function TutorFunctionalityTest10sButtonPushed(app, event)
            timerVal = 10;
            app.timerLeft = timerVal;   
            app.timerCountdown.Value = '00:00:10';
            d = duration(0,0,10:-1:0);
            app.strD = string(d);
        end
    end

Now this works for just seconds, but doesn't work for miniutes, as I cannot do duration(0,1:-1:0,10:-1:0). How would I be able to go about this? I am really confused, as if I just do duration (0, 1:-1:0) - it just prodcues a 1X2 duration array with 0:1:0 and 0:0:0. All help is appriciated.