Objectives:
 Learn what an Arduino is and what it can do
 Learn what an LED is and how to use it
 Be able to wire and program an LED to blink
By the end of this session:
 You will know how to use an Arduino and have a better
understanding of how many electronic devices are
made
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A microcontroller with many inputs and outputs
which you can program to turn lights on, react to
button pushes, control motors and do many more
things. It acts as the ’brains’ in the circuits. You will
use it for every project.
Arduino Uno
A collection of holes that are connected together in lines
to easily join components together.
Breadboard
Wires to join the breadboard to the Arduino and
also to link connections on the breadboard.
Jumper Wires
LED stands for ‘Light Emitting Diode’. They are lights that
only work when they are used the correct way around.
LED’s
Resistors come in many different values, and have different
coloured stripes, they are used to protect LEDs from getting
destroyed by too much current
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1)
Place the breadboard on the table. As shown in
the picture, each column is connected together
inside. (All of the red holes are connected
together, but they are separate from the
yellow column.)
2)
Look at the LED, you will see that one leg is
shorter than the other, and that one side of the
plastic is flat. Make sure that the flat side (short
leg) is facing left (<- side).
3)
Push the resistor into the breadboard, it does not
matter which way around it goes in.
4)
Push a wire into the Arduino’s pin
13 and into the column with the
resistor.
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5)
Connect a wire between the Arduino ‘s GND pin and the column in which
the short leg of the LED is inserted.
NOTE:
Pin 13 is special, it is attached to an LED on the Arduino already, so you don’t
have to wire one up separately on a breadboard like this, however it is
important to learn how it works .
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1)
Plug the USB cable into the Arduino and Computer, then open the Arduino
Program.
2)
Visit the webpage where you found this document —and copy and paste the
‘Blink template program’ into the Arduino window.
3)
An Arduino program has two main
sections:
The setup function runs once at the start
of the program, then the loop function
runs over and over again. When it gets to
the end, it starts the loop function again.
4)
Firstly, type this line to tell the program,
that we want to call pin 13 ‘LED’.
In the setup function we need to tell the
Arduino that we want ’LED’ to be an
output.
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5)
Now, the Arduino knows that we have an LED connected to pin 13, so we
just need to tell it what we want it to do with it.
Firstly, make it blink an LED (turn it on and off) over and over again. To do
this we need to write code in the loop section:
HIGH means turn on
LOW means turn off
Delay(1000); means delay 1 second
6)
Upload the program by clicking on the upload button.
7)
Your LED should turn on and off every second. This is because even though
you only wrote code to turn it on and off once, because it is in the loop
function, it repeats forever!
Try changing the delay number to 200 or 2000, repeat step 6 and watch
what happens.
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8)
Try connecting another LED in the breadboard as shown in the diagram.
You will need to connect it to a pin other than pin 13, say pin 12, then
connect the other side to the GND pin.
You will see that the black wire connects the two LED’s together, but
since the first LED’s leg was connected to GND, both LED’s legs become
connected to GND.
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9)
We need to tell the program that we have added another LED.
Firstly, we need to give it a name
We need to tell it that LED1 is an
output
We then need to tell it what we
want it to do.
Here it is turning LED1 off and LED
on, then waiting a second before
doing the opposite.
10)
Upload the program by clicking on the upload button.
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11)
You should see the LEDs flashing alternately. Try experimenting and moving
the ‘digitalWrite’ lines so that both LED’s flash at the same time, or make
them on for a long time and off for a short time.
Remember, whenever you change the program, you need to click the
upload button to see the new program working!
Extension task
Extension task
If you finish all of these steps,
remove your wires from the
Arduino and plug in the circuit
board as shown in the picture.
If you finish all of these steps,
remove your wires from the
Arduino and plug in the circuit
board as shown in the picture.
The LEDs are connected as follows:
The
board
contains
LEDs
connected to pins 9, 10, 11, 12 and
13. Use these numbers in your
program and make them flash
alternately, or scroll along the row.
Red: pin 11
Amber: pin 12
Green: pin 13
Try and make a program to make
them light in a Traffic light
sequence.
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