Have fun And Learn Electronics using ArduinoTM

118 Pages·4.085 MB·English

by  Hudson T.

Preface
This book is intended for those who are hobbyists and want to learn about
electronics and have fun at the same time. Each project explains the theory of the
sensor or device and a schematic (wiring diagram) and breadboard view are given
for each project. The code for each project is included, which can be copied and
pasted onto your PC/MAC.
There are 19 projects and the last one is a practical application of several of the
projects in the book. Once you learn how to use this device, the sky’s the limit to
what you can build.
At the end of the book an appendix of all of the Arduino™ commands used in the
book.
Acknowledgements
This book makes extensive use of the Arduino™ IDE and refers to Arduino products
and code created with the Arduino™ software. These files are licensed under a
Creative Commons Attribution Share-Alike license.
Many thanks to the Arduino Trademark team for their help.

Also many thanks to my wife for her support whilst writing this book.
Introduction
Welcome to the world of microcontrollers. Basically that’s what the Arduino™ and
its rival Raspberry Pi are.

Firstly we will look at the versions that are on the market at the moment. There are
over 16 versions of the Adruino, which most of them are listed below:
UNO
Galileo
YUN
BT
Mega 2560
MEGA ADK
Due
Nano
Ethernet
Esplora
Leonardo
Pro Mini
Micro
Mini
Pro
Fio

Of all of these boards the UNO is the most popular board and is the one that most
manufacturers sell with starter kits that are on the market.

The board is reasonably small having dimensions 68.6 x 53.4 mm. It can be
powered either by the USB port or with a regulated DC power supply (centre
positive) between 7 – 20v, but it is not recommended that you use over 12v as it will
overheat the voltage regulator, which will cause early failure of the board. A battery
pack may also be used connected to the Vin header pin and Grd header pin.
USB Connector
External PSU connector

Alternative PSU connector

The USB cable which is usually supplied with the board is a standard A – B cable
like you would use to connect to a printer.

Now we have sorted out how we are going to supply the board, we need to explain
how to program it.

Before you can do this you will need to download some software onto your PC or
Mac. This can be downloaded from the Arduino™ site: (http://www.Arduino™
.cc/en/Main/Software)
Once the software has been installed, which may take a few minutes, click on the
icon on your desktop that looks like an infinity sign (number 8 on its side). You will
get the following screen on your computer.
In Arduino™ speak; a program is called a Sketch. It has three main sections:
1. Library file includes
2. void setup() {
}
3. void loop() {
}
Don’t worry about the programming language at this stage as there are plenty of
public domain programs written that you will be able to use.
There are a few things you may need before tackling the Projects in this book:
Obviously you will need to purchase the Arduino™ UNO board.
Some companies sell kits which include most of the parts you require when using
this book.
You will also need:
Sets of jumper wires of different lengths (Male to Male)
also a few jumper wires (Male to Female)
Red LEDs
Green LEDs
Yellow LEDs
220R Resistors
10K Resistors
100k Potentiometer
1602 Liquid Crystal Display
A couple of lengths of header strip (40Pin 2.54mm Male PCB Single Row Straight
Header Strip)
RGB LED
L293D IC
5 -6v DC Motor
7 Segment Display
74HC595 IC
NE555 Timer
Tilt switch

The following sensors:
Temperature sensor: LM35
Temperature/Humidity Sensor: DHT11
Barometric Pressure Sensor BMP085
Photocell
Relay Module
Servo
Accelerometer ADXL33
This book will be laid out in the following format:
Title
Parts
Theory
Schematic
Breadboard view
Code
Code explanation
Learning Outcomes
All code will in a coloured font; blue for complete code, red for snippets in
explanations.

We will start with a very simple example: How to make an LED blink.
Project 1
Blink an LED

Parts
Arduino™ UNO
Breadboard
LED (any colour)
220R resistor
Connecting wire

Theory

A Light Emitting Diode (LED) is a semiconductor which when current is passed
through it emits light. Most LED’s have a maximum voltage of approximately 1.7v
and a maximum current of 30mA. We will only run the LED at half its power, so we
will use a current of 15mA.
Using Ohms Law:
𝑉
𝑅 =
𝐼
5−1.7
𝑅 =
0.015
3.3
𝑅 =
0.015
𝑅 = 220Ω
Therefore we need to put a 220 ohms resistor in the circuit to minimise the current
on the LED.
What we need to do is switch the LED on for 1 second and off for 1 second. This will
be done in the code by putting a delay of 1000mS.
This is not theory but you need to get to grips with another piece of software that will
help you design your projects. This software is called Fritzing and it is free to
download. You will find it at the following site: http://fritzing.org/download/
With this software you can design the schematic diagram (circuit diagram) and
design the layout on a breadboard as well as writing the code for the project.
Schematic

Breadboard View
Code
/*
Blink
Turns on an LED on for one second, then off for one second, repeatedly.

Most Arduino™ s have an on-board LED you can control. On the Uno and
Leonardo, it is attached to digital pin 13. If you're unsure what
pin the on-board LED is connected to on your Arduino™ model, check
the documentation at http://Arduino™ .cc

This example code is in the public domain.

modified 8 May 2014
by Scott Fitzgerald
*/

// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin 13 as an output.
pinMode(13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}

Code explanation
Now let us look at this code in more detail.
As we found out previously the code is split into 3 sections. As this is a very simple
Project it does not require running a Library file to make it work. We will talk about
these later on.
In the setup code we have the following:
void setup() {
// initialize digital pin 13 as an output.
pinMode(13, OUTPUT);
}

The // denotes that what follows on that line is a comment.
The next line is the important one! It tells the processor that pin 13 is outputting a
voltage signal using the function pinMode.
void loop() {
digitalWrite(13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}

The second part of the code is the part that does the business. As the LED is
connected to pin 13, the line: digitalWrite(13, HIGH); makes the output go high (5v).
It then delays for 1000mS (1 sec) and then the command: digitalWrite(13, LOW);
turns it off again for 1 sec. As it is in a loop it returns to the first command in the loop
and switches it on again and off after 1 sec. It will keep doing this for ever, as long
as the board is powered.

Now we know how it works we will upload it onto the UNO board. With the circuit
connected as in the Breadboard view we will now connect it to our computer. With
the USB A type connector connected to your computer, connect the other end to the
UNO board. All being well the small ON LED on the board will light up
The first thing we need to do is check that the code is error free. At the top of the
window under File there is a Tick icon, the Verify button. When you click on this
button it will start verifying. It will say in the area under the code that it is Compiling
Sketch and there will be activity in the black area underneath. This process may
take a few minutes depending on the complexity of the code and the speed of your
computer.

When it has finished the following screen is displayed and Done Compiling is written
in the area below the code.