hi my name is Massimo Banzi and I'm one
of the cofounders of the Arduino welcome
to this series of video about the
Arduino starter kit in this particular
video we're going to start learning the
basics of all the components we're going
to use in the rest of the videos so what
we see here is a set of electronic
components and today we're going to
build a very basic circuit we're going
to use a small LED connected to up to a
button and when you press the button the
LED comes on it's a very simple
electronic circuit that doesn't involve
our Arduino board at all and it's
designed for you to understand all the
basic elements that make an electronic
circuit so what is an LED the LED is a
small source of light you can imagine
it's like a light bulb but it's more
efficient because it doesn't generate
that much heat because it's electronic
component based on a semiconductor so
LEDs are very convenient for us because
they work at as small voltage so they
can be powered by a small battery or the
voltage that you can get from an Arduino
board so what is the circuit a circuit
is a series of electronic components
like this LED or this button connected
together using wires electricity can
flow through the components and each
component is either able to transform
the electricity into something else like
light like the LED does or for example
the switch is a component that can open
and close a circuit when you press on it
this particular button that I have in my
hand
it keeps the circuit closed until I
press the button and then it closes the
circuit closing the circuit is like a
little bit like when you open a tab you
let the electricity flow through the
button electricity you can imagine is
like water and the wires that we are
using to make the connections are like
pipes so the source of electricity is
essentially the equivalent of something
that pushes water into the pipes so the
first circuit that we are going to build
is going to have a source of electricity
pushing the current through the wires a
number of wires that connect the button
then the button will open and close the
circuit and when the circuit is closed
the current will flow through the LED
and then we will use another component
that I have here called resistor what
happens is that the voltage of our
battery is too high for the LED that we
are using just to give you an idea we're
going to be using a source of
electricity operating at five volts
which is the standard voltage at which
the Arduino board operates but this LED
is only going to need about one point
seven volts so how do we make sure that
the LED doesn't take too much current
where are we going to use a resistor and
this resistor is going to limit the
amount of current that flows through the
LED keeping it at the optimum amount of
voltage and current how do we make the
connection
well actually what happens with circuits
is that you can take wires and you can
wrap them around and you can create
circuits like that but it's not very
practical if you want to do a lot of
experimentation if you want to move
components around if you want to try
different kind of circuits wrapping
wires around you're not exactly the best
idea so what we're going to do we're
going to use this component that you see
here it's called a breadboard the
breadboard essentially provides a set of
prearranged connections and each one of
these holes is actually connected
underneath with a metallic spring so
when I plug a wire into the breadboard
the spring will hold on to the wire and
it will connect to all the other holes
in the same line of holes so let's have
a look for example this line of holes
that I am pointing to at the moment they
are all connected together so if I plug
this wire in this hole all the holes in
the same column are going to be
connected to this wire so if I take for
example this resistor and I plug the
resistor in one hole in the same line
for example here this is okay
so at the moment the resistor and the
wire are connected together if I move
this wire to the hole next to it they
are not connected anymore because only
the wires in the same column are
connected together so to explain this
concept better
I have prepared here a circuit that
contains a lot of all the basic elements
that I told you about this is the
resistor this is the push-button this is
the LED and this is a wire so what's
missing here is the source of power what
a circuit needs in order to operate is a
source of electricity in this case we're
going to use the Arduino board as a
source of electricity the Arduino board
can be powered through a battery or
through a USB connection as you can see
in this particular situation we're not
going to use the intelligence provided
by the Arduino board we're just going to
use the power that come that you can
take from the Arduino board in order to
learn how to build the circuit on a
breadboard
so we're going to connect this wire to
the other leg of the resistor you will
notice that actually the holes on this
side of the breadboard
they have a different pattern so why is
this because actually these two lines of
holes they follow a different connection
pattern so the ones they cover the main
area of the breadboard as I said are all
connected along the column while these
lines are going all the way from one end
to the other so these are two separate
strips of holes and each one of them is
connected together so for example if I
plug this red wire at the beginning of
this line of holes I'm actually
connecting 5 volts to every single hole
that you can see on this line here so
this means that the resistor is now
connected to this hole now I'm going to
take this black wire and I'm going to
plug it in one of these two holes that
are marked G and D G and E is the ground
it also represents the - on your battery
if you
look at the battery normally there's a
plus and a minus so 5v represents the
Plus on this ideal battery and the minus
is here represented by G and D so if I
connect the black wire to the other line
on the breadboard now I have connected
five volts the first lines of holes and
the black wire to the second line of
holes
now if everything is done correctly if I
press the button I'm going to connect
the resistor to the LED this will
complete the circuit and the LED will
light up Wow okay it's working okay that
was good so the ability to convert
electricity into another physical
phenomena that we can actually
experience in the real world makes the
LED a transducer so the transducer is a
component which is able to convert
electricity into something else or for
example if there were a component that
would convert light back into
electricity that would also be a
transducer in particular we call the LED
in this particular situation an
activator because it takes electricity
and then turns into something that I can
actually see in the real world in this
case I can see the light electricity is
invisible to me but the LED makes a
literacy visible by turning it into
light we have our completed circuit and
I would like to make some modifications
now to introduce some other concepts so
what we are looking at here is a very
simple circuit where each component is
connected to two the next component in
the circuit and then the last connection
goes back to G and D so you can imagine
the current flows from the red wire into
the circuit through the resistor through
the push button there in this wire then
through this LED another wire back to
ground so this is how the circuit is
closed one of the features of this
circuit is that the elements we say are
connected in series because one
component comes
after the other and we can make this
circuit a little bit more complicated
because at the moment we have only one
button so what happens if I connect
another button so I can remove this
jumper and then I'm going to add another
push button making sure that it's
connected with the LED so now when I
press these patterns nothing happened
because the circuit is still open we
have to close the circuit using one of
these wires so I will plug the wire here
I will plug the other wire here and if
everything works out I press the button
and still nothing happens why because
these two buttons are connected in
series so they are one after the other
if I want to operate the circuit ready
to press both buttons at the same time
so look at this when I press button
number one and button number two the
current is able to flow through the
circuit when I release one of the
buttons the circuit is open and it stops
operating so what we have learned now is
that if we put buttons in series so one
after the other I need to press all of
them in order to close the circuit and
make this electricity flow inside the
push-button there are two pieces of
metal that are separated by a spring
when you press the button these two
pieces of metal they come in contact and
they create an electrical connection and
the electricity can flow to them when
you release the button the spring pushes
the 2-part piece of metal away and it
interrupts the circuit it opens the
circuit so you will notice that the push
button has got four legs at the moment
we used only two what are the other two
legs doing well actually they are
internally connected to the first set of
legs so the two legs on this side of the
push button are internally connected
together and the two legs on this side
of the push button and internally
connected together so this increases the
number of combination
you can use when you create circuits and
so what happens is that if I take this
jumper that I use to build this circuit
I can actually mount it behind the push
buttons and the circuit still works so
what you will notice at this point in
the circuit and this point the circuit
are exactly the same and here this point
and this point are exactly the same so
when I press the button these two points
in the circuit are connected with these
two points in the circuit when I release
the button only these two points are
connected and these two points are
connected individually but there is no
connection between the four of them so
this allows me to try to create another
connection that we call parallel
connection the idea is that we can
actually place one button next to the
other and we can create two different
paths that the current can use to
actually throw through let's see what
happens if we put these two push buttons
in parallel so what I'm going to do I'm
going to use two jumpers so I'm going to
connect one leg of the first push-button
with the same leg on the second
push-button and I'm going to do the same
for the remaining contact one and two so
what happens here is that if I press the
button now the LED comes on and if I
press the other button the other LED
comes on and if I press both of them the
LED comes on at the same time so what's
happening here is that by creating two
different path for the current to flow
through I just need to press one of the
two buttons for the current to reach the
LED and light up if you put the buttons
in series you need to press one button
and the other button in order to create
light and in this particular
configuration you need to press one
button or the other button in order to
turn on the LED so in a way this small
circuit is creating a very basic logic
circuit one that has an end logic you
need to press one button and the
other in order to light up the LED and
the second one is an or circuit you
press one button or the other that's all
for today I hope you enjoyed the
tutorial and remember build it hack it
share it because Arduino is you