Arduino Tut. #7 - Button Debouncing - Software & Hardware Video Lecture

how's it going guys welcome to the
seventh argument tutorial in which we're
going to discuss what are the basic
concepts that I wanted to discuss a long
time ago but never got around to it so
that would be button debouncing so as
you can see I have a small setup where I
have two LEDs on the bread board along
with a button which is used to toggle
the LEDs and currently there is no
button debouncing present and my
software or hardware as you can see if I
if I keep just pressing the button you
would see the LEDs blinking sometimes so
I'm going to discuss the concept of the
whole button debouncing and what's
happening exactly in a separate video
but I actually wanted to show you what
is actually happening in the hardware so
as you can see sometimes I press and the
LEDs quickly blink and they don't just
saw as you would expect them to so let's
take a look at the code what which I
have right now and see how we can first
of all debounce and software and then
I'm also going to explain how you can
debounce in hardware so stay tuned
alright so they can look at the sketch
that I have currently uploaded in on the
Arduino as you can see I have a button
and two LEDs declared I also have a
boolean for to keep the state of the
button and I have a toggle which is also
a boolean I'm going to explain that in a
second what it does in the setup
function I have two LEDs as output one
button as an input and arbitrarily I
have declared two LEDs one high one low
just for starting purposes and the loop
as you can see I write a digital read of
the button high and if that is the case
I'm going to say that the button is
pressed that is set to true otherwise it
is false and the toggle is false so what
this creates is a situation where I can
actually check if the button has been
pressed once or it has been just held
down and what that basically means is
that if I just hold my finger on the
button
I'm not going to just keep on toggling
the LEDs during that process I'm only
going to toggle at once so once again
because of that issue I have to check
for if the button is pressed is true and
the toggle is currently false so that
means that the toggle has not been
executed yet so it if it has not been
executed I execute it once so I set it
to true and I execute the function
toggle which is basically setting LED
LEDs to the opposite of the of what they
currently are so in order to make this
fukin debounce able I'm going to
actually go ahead and add a condition so
I'm going to add an int bounce which is
which I'm going to set to zero for now
I'm going to change this button is
pressed true because I'm going to add a
condition so if it is high I'm going to
simply increment the bounce so we're
going to increment the bounce we're also
going to say that the bounce is going to
be reset back to zero in case of the
button not being pressed anymore or the
button going back to low and we are also
going to add an if statement so if
debounce bigger equal to and I have
tested several values for this case so
in my case 5000 worked pretty well you
can experiment on your own this value is
basically going to indicate how long you
wait to be certain that the button is
actually not bouncing any more so you
may set this to something lower it
depends on your on many factors notably
your button so in this case I am going
to say button pressed equals to true
and this should be about all we need for
button D bouncing so let's check the
sketch and upload it and once again this
is the value which indicates how long
you need to wait before accepting that
the button was pressed so just to
explain this a little bit you may set
this to a lower lower value so for
example 500 or even 50 but the lower you
set it the less time you give yourself
to pick the D bones so preferably you
would like to set it as long as you can
without having a delay in your button so
let's take a look at what our same setup
does right now alright so we have our D
bouncing implemented so as you can see
no matter how hard I try the LEDs are
responding perfectly to my button
presses you no longer see them
flickering here and there so obviously
if I if I try and sort of press
extremely fast that's only the contact
not making um sort of the closure and
it's not actually the button bouncing
effect so let's take a look at the
hardware solution that we can also
implement alright so if you have noticed
this is my current setup for the button
so as you can see the pen is normally
pulled down low and once you press the
button it goes too high so that's what
I'm detecting in my software so what
happens is when this contact makes
basically when I create this contact
with the button it goes high low high
low which is the bouncing of the button
but if you were to insert a capacitor
right here basically you would have a
low on this capacitor right so zero
volts and when you press the button
instead of going up instantly this
voltage would actually take time to go
to five volts depending on the capacitor
value so that is one way that you can
debounce the button through hardware so
thank you guys for watching these are
the two methods which you can use to do
bounce your buttons right now so the
hardware method as well as the software
that I explained in the extended version
I would like to touch up on button D
bounce and a little bit more and
actually explain the concept so take a
look at that I'm going to post a link in
the description thank you very much if
you've enjoyed the video make sure to
leave me a comment if you have a
question post it down there as well if
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