Arduino uno User Manual

3.6V, and the maximum current often is 20 mA (milliamperes). Let’s say we
have an LED with a maximum of 2.5 volts and a safe current of 20 mA. We
also assume that we have a power supply delivering 5 volts (as most Arduinos
do). What’s the right size of the resistor we need to put in front of the LED?
We have to make sure that the resistor takes 5 – 2.5 = 2.5 volts from the cir-
cuit, so only 2.5 volts are left for the LED. This value is called voltage drop.
Also, we want a maximum of 20 mA to flow through the LED. This implies
that a maximum of 20 mA (0.02 A) should flow through our resistor also.
Now that we know that 2.5V and 0.02 A should pass the LED, we can use
Ohm’s law to calculate the resistance R:
R = V / I
In our case, we have the following:
R = 2.5V / 0.02A = 125Ω
This means we need a 125Ω resistor for our LED. If you do not have a 125Ω
resistor, use a bigger one, such as 150Ω or 220Ω. It will still protect the LED
and only slightly decrease its brightness. That’s because we’d decrease the
current even more:
I = 2.5V / 150Ω = 17mA
I = 2.5V / 220Ω = 11mA
Resistors
You’ll hardly ever find an electronics project that doesn’t need resistors. So,
you’ll need them often and should get more familiar with them. Usually you’ll
use carbon or metal resistors. Metal resistors are more precise and don’t
create so much noise, but carbon resistors are cheaper. In simple circuits, it
usually doesn’t matter which type you use.
The most important attribute of a resistor is its resistance value that is mea-
sured in ohms. Only a few vendors actually print this value on the resistor,
because resistors are small parts, and it’s hard to read text that is small
enough to fit on them. So, they use a trick and encode the value using colored
stripes.
Usually you find four or five stripes on a resistor (at least on through-hole
parts; SMD resistors don’t have them). One of them is separated from the
others by a gap. (See the following figure.) The separate stripe is on the right
side of the resistor, and it tells you about the resistor’s accuracy. Gold stands
for an accuracy of ±5 percent, silver stands for ±10 percent, and no stripe
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Arduino uno Specifications

General

Form factor	Arduino
Certification	RoHS, FC, CE
Processor model	-
Processor frequency	- MHz
Microcontroller model	ATmega328
Microcontroller frequency	16 MHz
DC input voltage	7-12 V
Operating voltage	5 V
DC current per I/O pin	40 mA
Flash memory	0.032 MB
Maximum internal memory	- GB
SRAM (Static Random Access Memory)	2 KB
EEPROM (Electrically Erasable Programmable Read-Only Memory)	1 KB
Wi-Fi	No
Number of analog I/O pins	6
Number of digital I/O pins	14

Weight and Dimensions

Board dimensions	53.4 x 68.6 mm

Summary

Arduino Uno and the Arduino Platform

The Parts You Need

Chapter 1: Welcome to the Arduino

What Exactly Is an Arduino?

Exploring the Arduino Board

Analog and Digital Signals

Installing the Arduino IDE

Provides step-by-step instructions for installing the Arduino Integrated Development Environment.

Meeting the Arduino IDE

Hello, World!

Introduces the first project: making an LED blink using the Arduino.

Compiling and Uploading Programs

Explains how to compile and upload sketches to the Arduino board.

Chapter 2: Creating Bigger Projects with the Arduino

Managing Projects and Sketches

Changing Preferences

Explains how to customize Arduino IDE settings for better workflow.

The Arduino Programming Language

Using Serial Ports

Explains serial communication for data exchange between Arduino and computer.

Chapter 3: Building Binary Dice

Working with Breadboards

Explains how breadboards work and how to connect components.

Using an LED on a Breadboard

First Version of a Binary Die

Implements the first version of a binary die using three LEDs.

Working with Buttons

Details how pushbuttons work and how to connect them to the Arduino.

Adding Your Own Button

Building a Dice Game

Completes the dice project by adding a guess button and game logic.

Chapter 4: Building a Morse Code Generator Library

Learning the Basics of Morse Code

Building a Morse Code Generator

Starts the implementation of the Telegraph C++ class.

Fleshing Out the Morse Code Generator’s Interface

Defines the Telegraph class interface and Morse code data arrays.

Outputting Morse Code Symbols

Installing and Using the Telegraph Class

Guides on integrating the custom Telegraph library into Arduino IDE.

Chapter 5: Sensing the World Around Us

Measuring Distances with an Ultrasonic Sensor

Introduces ultrasonic sensors and builds a distance measuring device.

Increasing Precision Using Floating-Point Numbers

Increasing Precision Using a Temperature Sensor

Integrates a temperature sensor to refine distance measurements.

Creating Your Own Dashboard

Chapter 6: Building a Motion-Sensing Game Controller

Wiring Up the Accelerometer

Details connecting the ADXL335 accelerometer to the Arduino.

Bringing Your Accelerometer to Life

Reads and outputs raw accelerometer data for three axes.

Finding and Polishing Edge Values

Building Your Own Game Controller

Integrates a pushbutton and refined accelerometer data for a game controller.

Chapter 7: Writing a Game for the Motion-Sensing Game Controller

Writing a GameController Class

Creates a JavaScript class for convenient access to Arduino motion data.

Creating the Game

Implements a Breakout clone using JavaScript and the motion controller.

Chapter 8: Generating Video Signals with an Arduino

How Analog Video Works

Building a Digital-to-Analog Converter (DAC)

Details building a binary-weighted DAC for video signal generation.

Connecting the Arduino to Your TV Set

Describes modifying an RCA cable to connect to the Arduino.

Using the TVout Library

Introduces the TVout library for generating video signals on a TV.

Building a TV Thermometer

Creates a graphical thermometer display on a TV screen using sensors.

Working with Graphics in TVout

Chapter 9: Tinkering with the Wii Nunchuk

Wiring a Wii Nunchuk

Details wiring the Nunchuk controller to Arduino analog pins.

Talking to a Nunchuk

Building a Nunchuk Class

Creates a C++ class for interfacing with the Nunchuk controller.

Using Our Nunchuk Class

Demonstrates reading Nunchuk data (joystick, accelerometer, buttons).

Creating Your Own Video Game Console

Creating Your Own Video Game

Handling the Different Game States

Chapter 10: Networking with Arduino

Using Your PC to Transfer Sensor Data to the Internet

The Arduino and the Internet of Things (IoT)

Registering an Application with Twitter

Tweeting Messages with Processing

Communicating Over Networks Using an Ethernet Shield

Using DHCP and DNS

Chapter 11: Creating a Burglar Alarm with Email Notification

Emailing from the Command Line

Detecting Motion Using a Passive Infrared Sensor

Bringing It All Together

Chapter 12: Creating Your Own Universal Remote Control

Understanding Infrared Remote Controls

Grabbing Remote Control Codes

Cloning a Remote

Using the TvRemote class

Controlling Infrared Devices Remotely with Your Browser

Building an Infrared Proxy

Chapter 13: Controlling Motors with Arduino

What You Need

Lists components for motor control: servo motor, wires, Arduino.

Introducing Motors

First Steps with a Servo Motor

Building a Blaminatr

What If It Doesn’t Work?

Troubleshooting motor control: power consumption, weight, adjustments.

APPENDIX 1: Electronics and Soldering Basics

Current, Voltage, and Resistance

Electrical Circuits

Resistors

Learning How to Solder

APPENDIX 2: Advanced Arduino Programming

The Arduino Programming Language

Bit Operations

APPENDIX 3: Advanced Serial Programming

Learning More About Serial Communication

Serial Communication Using Various Languages

APPENDIX 4: Controlling the Arduino with a Browser

What Are Google Chrome Apps?

Creating a Minimal Chrome App

Exploring the Chrome Serial API

Writing a SerialDevice Class