00 Introduction

BECOME EXTRAORDINARY

Everyone, every day, uses technology. Most of us leave the programming to engineers because we think coding and electronics are complicated and difficult; actually, they can be fun and exciting activities. Thanks to Arduino, designers, artists, hobbyists and students of all ages are learning to create things that light up, move, and respond to people, animals, plants, and the rest of the world.
Over the years Arduino has been used as the “brain” in thousands of projects, one more creative than the last. A worldwide community of makers has gathered around this open-source platform, moving from personal computing to personal fabrication, and contributing to a new world of participation, cooperation and sharing.
Arduino is open and simple. It’s founded on lessons we’ve learned teaching our own classes: if you start with the assumption that learning to make digital technologies is simple and accessible, you can make it so. Suddenly electronics and code become creative tools that anyone can use – like brushes and paint. This book walks you through the basics in a hands-on way, with creative projects you build by learning. Once you’ve mastered the basics, you’ll have a palette of software and circuits that you can use to create something beautiful, and make someone smile with what you invent.

Welcome to Arduino!

ARDUINO MAKES IT AS EASY AS POSSIBLE TO PROGRAM TINY COMPUTERS CALLED MICROCONTROLLERS, WHICH ARE WHAT MAKE OBJECTS INTERACTIVE

You are surrounded by dozens of them every day: they are embedded in timers, thermostats, toys, remote controls, microwave ovens, even some toothbrushes. They just do one specific task, and if you hardly notice them – which is often the case – it’s because they are doing it well. They have been programmed to sense and control activity using sensors and actuators.
Sensors listen to the physical world. They convert energy that you give off when you press buttons, or wave your arms, or shout, into electrical signals. Buttons and knobs are sensors that you touch with your fingers, but there are many other kinds of sensors.
Actuators take action in the physical world. They convert electrical energy back into physical energy, like light and heat and movement.
Microcontrollers listen to sensors and talk to actuators. They decide what to do based on a program that you write.
Microcontrollers and the electronics you attach to them are just the skeleton of your projects, though. You’ll need to bring skills you probably already have to put some flesh on the bones.
For example, in one of the projects we suggest, you’ll make an arrow and attach it to a motor, and put them both in a box with a knob, so you can make a meter to tell people whether you’re busy or not. In another, you’ll put some lights and a tilt switch on a cardboard frame to make an hourglass.
Arduino can make your projects responsive, but only you can make them beautiful. We’ll provide some suggestions along the way as to how you might do that.
Arduino was designed to help you get things done. To make that happen, we kept the background material on programming and electronics to a minimum. If you decide you want to know more about these aspects, there are lots of good guides available. We’ll provide a couple of references, and you can find more online at: arduino.cc/starterkit

PARTS IN YOUR KIT

Arduino Uno - The microcontroller develop-ment board that will be at the heart of your projects. It’s a simple computer, but one that has no way for you to interact with it yet. You will be building the circuits and interfaces for interaction, and telling the microcontroller how to interface with other components.
Battery Snap - Used to connect a 9V battery to power leads that can be easily plugged into a breadboard or your Arduino.
Breadboard - A board on which you can build electronic circuits. It’s like a patch panel, with rows of holes that allow you to connect wires and components together. Versions that re-quire soldering are available, as well as the sol-der-less type used here.
Capacitors - These components store and re-lease electrical energy in a circuit. When the circuit’s voltage is higher than what is stored in the capacitor, it allows current to flow in, giv-ing the capacitor a charge. When the circuit’s voltage is lower, the stored charge is released. Often placed across power and ground close to a sensor or motor to help smooth fluctuations in voltage.
DC motor - Converts electrical energy into me-chanical energy when electricity is applied to its leads. Coils of wire inside the motor become magnetized when current flows through them.These magnetic fields attract and repel mag-nets, causing the shaft to spin. If the direction of the electricity is reversed, the motor will spin in the opposite direction.
Diode - Ensures electricity only flows in one di-rection. Useful when you have a motor or other high current/voltage load in your circuit. Di-odes are polarized, meaning that the direction that they’re placed in a circuit matters. Placed one way, they allow current to pass through. Placed the other way, they block it. The anode side generally connects to the point of higher energy in your circuit. The cathode typically connects to the point of lower energy, or to ground. The cathode is usually marked with a band on one side of the component’s body.
Gels (red, green, blue) - These filter out differ-ent wavelengths of light. When used in con-junction with photoresistors, they cause the sensor to only react to the amount of light in the filtered color.
H-bridge - A circuit that allows you to control the polarity of the voltage applied to a load, usually a motor. The H-bridge in the kit is an in-tegrated circuit, but it could also be construct-ed with a number of discrete components.
Jumper wires - Use these to connect compo-nents to each other on the breadboard, and to the Arduino.
Light Emitting Diodes (LEDs) - A type of diode that illuminates when electricity passes through it. Like all diodes, electricity only flows in one direction through these components. You’re probably familiar with these as indicators on a variety of electronic devices. The anode, which typically connects to power, is usually the long-er leg, and the cathode is the shorter leg.
Liquid Crystal Display (LCD) - A type of alpha-numeric or graphic display based on liquid crys-tals. LCDs are available in a many sizes, shapes, and styles. Yours has 2 rows with 16 characters each.
Male header pins - These pins fit into female sockets, like those on a breadboard. They help make connecting things much easier.
Optocoupler - This allows you to connect two circuits that do not share a common power supply. Internally there is a small LED that, when illuminated, causes a photoreceptor in-side to close an internal switch. When you ap-ply voltage to the + pin, the LED lights and the internal switch closes. The two outputs replace a switch in the second circuit.
Piezo - An electrical component that can be used to detect vibrations and create noises.
Photoresistor - (also called a photocell, or light-dependent resistor). A variable resistor that changes its resistance based on the amount of light that falls on its face.
Potentiometer - A variable resistor with three pins. Two of the pins are connected to the ends of a fixed resistor. The middle pin, or wiper, moves across the resistor, dividing it into two halves. When the external sides of the poten-tiometer are connected to voltage and ground, the middle leg will give the difference in voltage as you turn the knob. Often referred to as a pot.
Pushbuttons - Momentary switches that close a circuit when pressed. They snap into bread-boards easily. These are good for detecting on/off signals.
Resistors - Resist the flow of electrical energy in a circuit, changing the voltage and current as a result. Resistor values are measured in ohms (represented by the Greek omega char-acter: Ω). The colored stripes on the sides of resistors indicate their value (see resistor color code table).
Servo motor - A type of geared motor that can only rotate 180 degrees. It is controlled by sending electrical pulses from your Arduino. These pulses tell the motor what position it should move to.
Temperature sensor - Changes its voltage out-put depending on the temperature of the com-ponent. The outside legs connect to power and ground. The voltage on the center pin changes as it gets warmer or cooler.
Tilt sensor - A type of switch that will open or close depending on its orientation. Typically they are hollow cylinders with a metal ball in-side that will make a connection across two leads when tilted in the proper direction.
Transistor - A three legged device that can op-erate as an electronic switch. Useful for controlling high current/high voltage components like motors. One pin connects to ground, another to the component being controlled, and the third connects to the Arduino. When the com-ponent receives voltage on the pin connected to an Arduino, it closes the circuit between the ground and the other component.
USB Cable - This allows you to connect your Arduino Uno to your personal computer for programming. It also provides power to the Ar-duino for most of the projects in the kit.

TABLE OF SYMBOLS

UNCONNECTED WIRES
TILT SWITCH
RESISTOR
LED
POLARIZED CAPACITOR
GROUND
CONNECTED WIRES
TRANSISTOR
MOSFET
PHOTO RESISTOR
DIODE
CAPACITOR
PUSHBUTTON
MOTOR
POTENTIOMETER
PIEZO
BATTERY
In this book we will show you circuits both with realistic illustrations and with schematic diagrams.
Illustrations will give you an idea of what the breadboard might look like in one possible implementation of the project. Schematics, instead, use symbols to capture the essence of circuits: they present the components and the ways they are connected in a clear, succinct, and unambiguous form, but not their physical organization. Schematics and schematic symbols are how we communicate about circuits. As you explore the world of electronics you will discover that some books and websites only provide schematic diagrams, so learning to read circuits this way is a valuable skill.
Here are the symbols we will be using throughout the book.