Timing button presses code

When running my code I would like it so that when a button is pushed on, a timer will start and when the button is pushed again the timer will stop and display the time it took from when the button was pushed on to when it was pushed off. The following is my current code but the tic toc does not work.

a = arduino; %register Arduino Uno
while 1==1 %make code continuous
    pin1 = readDigitalPin (a, 'D2'); %continuously read button 1
    pin2 = readDigitalPin (a, 'D4'); %continuously read button 2
    pin3 = readDigitalPin (a, 'D6'); %continuously read button 3
    pin4 = readDigitalPin (a, 'D8'); %continuously read button 4
    if pin1==1 %if button 1 is pushed
        tic
        writeDigitalPin(a, 'D10', 1); %turn on RGB LED to green
    else %when button 1 is pushed again
        writeDigitalPin(a, 'D10', 0); %RGB LED turns off
        toc
    end
    if pin2==1 %if button 2 is pushed
        tic
        writeDigitalPin(a, 'D13', 1); %turn on yellow LED
    else %when button 2 is pushed again
        writeDigitalPin(a, 'D13', 0); %LED turns off
        toc
    end
    if pin3==1 %if button 3 is pushed
        tic
        writeDigitalPin(a, 'D12', 1); %turn on red LED
    else %when button 3 is pushed again
        writeDigitalPin(a, 'D12', 0); %LED turns off
        toc
    end
    if pin4==1 %if button 4 is pushed
        tic
        writeDigitalPin(a, 'D11', 1); %turn on RGB LED to blue
    else %when button 4 is pushed again
        writeDigitalPin(a, 'D11', 0); %RGB LED turns off
        toc
    end
end

Answer 1

[Rik]

You need to review your logic. What conditions are true when a button is pressed for the first time? And how do those conditions differ from what happens when the button is pressed a second time? You probably need to keep track of whether a timer is running. If you use code like I wrote below it is easier to change behavior and add or remove pins as needed.

Note that ==1 is only needed if pin_value can also have other non-zero values.

pins=struct;
pins(1).read='D2';
pins(1).write='D10';
pins(1).RunningTimer=false;
pins(1).tic_handle=[];
pins(2).read='D4';
pins(2).write='D13';
pins(2).RunningTimer=false;
pins(3).read='D6';
pins(3).write='D12';
pins(3).RunningTimer=false;
pins(4).read='D8';
pins(4).write='D11';
pins(4).RunningTimer=false;

a = arduino; %register Arduino Uno
while true %make code continuous
    for n=1:numel(pins)
        pin=pins(n);%store for shorter syntax
        pin_value=readDigitalPin(a,pin.read);
        if pin_value==1
            %button pushed
            if ~pin.RunningTimer % first time
                %start timer
                pin.tic_handle=tic;
                pin.RunningTimer=true;
                writeDigitalPin(a,pin.write,1);
            else
                %stop timer
                pin.RunningTimer=false;
                toc(pin.tic_handle)
                writeDigitalPin(a,pin.write,0);
            end
        else
            %button not pushed
        end
        pins(n)=pin;
    end
end

[Madison Gladstone]

The code does produce a timer however, When pressed the first time the led flashes, when pressed again the LED remains on but stops flashing, another press initates the flashing, and the fourth press turns off the led. How would you modify the code so that the led turns on and is not blinking for the first push and the second push turns it off and displays the time. Also after turning the led on and off with the button is there a way to store the times in a table and reset the time each time the led is turned on? Sorry for all the questions I am new at coding.

[Rik]

You can easily modify this code to store the time:

pin.TimeElapsed=toc(pin.tic_handle);

The benefit of that line is that it will automatically overwrite any previous measurement.

I don't have an arduino myself, so I can't test any of this code. My assumption was that you had an already working interface with the hardware, leaving only the Matlab part as an issue. If I had to guess I would say the code runs too fast, so it will read the pin multiple times for each press.

I can't test the behavior of readDigitalPin so you will have to do that on your own. Use the debugging tools. Put a breakpoint in this code and see what happens line by line.

[Madison Gladstone]

Thanks I will give it a try