Arduino

"Arduino Uno" Revision 3
Type	Single-board microcontroller
Website	www.arduino.cc

Arduino is an open-source computer hardware and software company, project and user community that designs and manufactures kits for building digital devices and interactive objects that can sense and control the physical world.^[1] Arduino boards may be purchased preassembled, or as do-it-yourself kits; at the same time, the hardware design information is available for those who would like to assemble an Arduino from scratch.

The project is based on a family of microcontroller board designs manufactured primarily by SmartProjects in Italy,^[2] and also by several other vendors, using various 8-bit Atmel AVR microcontrollers or 32-bit Atmel ARM processors. These systems provide sets of digital and analog I/O pins that can be interfaced to various extension boards and other circuits. The boards feature serial communications interfaces, including USB on some models, for loading programs from personal computers. For programming the microcontrollers, the Arduino platform provides an integrated development environment (IDE) based on the Processing project, which includes support for C and C++ programming languages.

The first Arduino was introduced in 2005. The project leaders sought to provide an inexpensive and easy way for hobbyists, students, and professionals to create devices that interact with their environment using sensors and actuators. Common examples for beginner hobbyists include simple robots, thermostats and motion detectors. Adafruit Industries estimated in mid-2011 that over 300,000 official Arduinos had been commercially produced,^[3] and in 2013 that 700,000 official boards were in users' hands.^[4]

Arduino started in 2005 as a project for students at the Interaction Design Institute Ivrea in Ivrea, Italy. At that time program students used a "BASIC Stamp" at a cost of $100, considered expensive for students. Massimo Banzi, one of the founders, taught at Ivrea.^[5] The name "Arduino" comes from a bar in Ivrea, where some of the founders of the project used to meet. The bar, in turn, was named after Arduino, Margrave of Ivrea and King of Italy from 1002 to 1014.^[6]

A hardware thesis was contributed for a wiring design by Colombian student Hernando Barragan. After the Wiring^[7] platform was complete, researchers worked to make it lighter, less expensive, and available to the open source community. The school eventually closed, but the researchers, including David Cuartielles, promoted the idea. The Arduino core team consisted of Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino and David Mellis.^[5]

An Arduino board consists of an Atmel 8-bit, 16-bit and 32-bit AVR microcontroller with complementary components that facilitate programming and incorporation into other circuits. An important aspect of the Arduino is its standard connectors, which lets users connect the CPU board to a variety of interchangeable add-on modules known as shields. Some shields communicate with the Arduino board directly over various pins, but many shields are individually addressable via an I²C serial bus—so many shields can be stacked and used in parallel. Official Arduinos have used the megaAVR series of chips, specifically the ATmega8, ATmega168, ATmega328, ATmega1280, and ATmega2560. A handful of other processors have been used by Arduino compatibles. Most boards include a 5 volt linear regulator and a 16 MHz crystal oscillator (or ceramic resonator in some variants), although some designs such as the LilyPad run at 8 MHz and dispense with the onboard voltage regulator due to specific form-factor restrictions. An Arduino's microcontroller is also pre-programmed with a boot loader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an external programmer. This makes using an Arduino more straightforward by allowing the use of an ordinary computer as the programmer.

At a conceptual level, when using the Arduino software stack, all boards are programmed over an RS-232 serial connection, but the way this is implemented varies by hardware version. Serial Arduino boards contain a level shifter circuit to convert between RS-232-level and TTL-level signals. Current Arduino boards are programmed via USB, implemented using USB-to-serial adapter chips such as the FTDI FT232. Some variants, such as the Arduino Mini and the unofficial Boarduino, use a detachable USB-to-serial adapter board or cable, Bluetooth or other methods. (When used with traditional microcontroller tools instead of the Arduino IDE, standard AVR ISP programming is used.)

The Arduino board exposes most of the microcontroller's I/O pins for use by other circuits. The Diecimila, Duemilanove, and current Uno provide 14 digital I/O pins, six of which can produce pulse-width modulated signals, and six analog inputs, which can also be used as six digital I/O pins. These pins are on the top of the board, via female 0.10-inch (2.5 mm) headers. Several plug-in application shields are also commercially available. The Arduino Nano, and Arduino-compatible Bare Bones Board and Boarduino boards may provide male header pins on the underside of the board that can plug into solderless breadboards.

There are many Arduino-compatible and Arduino-derived boards. Some are functionally equivalent to an Arduino and can be used interchangeably. Many enhance the basic Arduino by adding output drivers, often for use in school-level education to simplify the construction of buggies and small robots. Others are electrically equivalent but change the form factor, sometimes retaining compatibility with shields, sometimes not. Some variants use completely different processors, with varying levels of compatibility.

The original Arduino hardware is manufactured by the Italian company Smart Projects.^[9] Some Arduino-branded boards have been designed by the American company SparkFun Electronics.^[10] Sixteen versions of the Arduino hardware have been commercially produced to date.^[when?]

• Example Arduino boards
• 
  Arduino Diecimila in Stoicheia
• 
  Arduino Duemilanove (rev 2009b)
• 
  Arduino UNO
• 
  Arduino Leonardo
• 
  Arduino Mega
• 
  Arduino MEGA 2560 R3 (front side)
• 
  Arduino MEGA 2560 R3 (back side)
• 
  Arduino Nano
• 
  Arduino Due (ARM-based)
• 
  LilyPad Arduino (rev 2007)

Arduino and Arduino-compatible boards use printed circuit expansion boards called "shields", which plug into the normally supplied Arduino pin headers. Shields can provide motor controls, GPS, Ethernet, LCD, or breadboarding (prototyping). A number of shields can also be made DIY.^[11][12][13]

• Example Arduino shields
• 
  Multiple shields can be stacked. In this example the top shield contains a solderless breadboard.
• 
  Screw-terminal breakout shield in a wing-type format
• 
  Adafruit Motor Shield with screw terminals for connection to motors
• 
  Adafruit Datalogging Shield with a Secure Digital (SD) card slot and real-time clock (RTC) chip
• 
  HackARobot Fabric Shield – designed for Arduino Nano to hook up motors and sensors such as gyroscope or GPS, and other breakout boards such as WiFi, Bluetooth, RF, etc.

Arduino Software IDE

A screenshot of the Arduino IDE showing the "Blink" program, a simple beginner program
Developer(s)	Arduino Software
Stable release	1.6.3 / 2 April 2015 (2015-04-02)[14]
Written in	Java, C and C++
Operating system	Cross-platform
Type	Integrated development environment
License	LGPL or GPL license
Website	arduino.cc

The Arduino integrated development environment (IDE) is a cross-platform application written in Java, and derives from the IDE for the Processing programming language and the Wiring projects. It is designed to introduce programming to artists and other newcomers unfamiliar with software development. It includes a code editor with features such as syntax highlighting, brace matching, and automatic indentation, and is also capable of compiling and uploading programs to the board with a single click. A program or code written for Arduino is called a "sketch".^[15]

Arduino programs are written in C or C++. The Arduino IDE comes with a software library called "Wiring" from the original Wiring project, which makes many common input/output operations much easier. The users need only to define two functions to make an executable cyclic executive program:

• setup(): a function run once at the start of a program that can initialize settings
• loop(): a function called repeatedly until the board powers off

A typical first program for a microcontroller simply blinks an LED on and off. In the Arduino environment, the user might write a program like this:^[16]

#define LED_PIN 13

void setup() {
    pinMode(LED_PIN, OUTPUT);       // Enable pin 13 for digital output
}

void loop() {
    digitalWrite(LED_PIN, HIGH);    // Turn on the LED
    delay(1000);                    // Wait one second (1000 milliseconds)
    digitalWrite(LED_PIN, LOW);     // Turn off the LED
    delay(1000);                    // Wait one second
}

It is a feature of most Arduino boards that they have an LED and load resistor connected between pin 13 and ground; a convenient feature for many simple tests.^[16] The previous code would not be seen by a standard C++ compiler as a valid program, so when the user clicks the "Upload to I/O board" button in the IDE, a copy of the code is written to a temporary file with an extra include header at the top and a very simple main() function at the bottom, to make it a valid C++ program.

The Arduino IDE uses the GNU toolchain and AVR Libc to compile programs, and uses avrdude to upload programs to the board.

As the Arduino platform uses Atmel microcontrollers, Atmel's development environment, AVR Studio or the newer Atmel Studio, may also be used to develop software for the Arduino.^[17][18]

Arduino is open-source hardware: the Arduino hardware reference designs are distributed under a Creative Commons Attribution Share-Alike 2.5 license and are available on the Arduino Web site. Layout and production files for some versions of the Arduino hardware are also available. The source code for the IDE is available and released under the GNU General Public License, version 2.^[19]

Although the hardware and software designs are freely available under copyleft licenses, the developers have requested that the name "Arduino" be exclusive to the official product and not be used for derivative works without permission. The official policy document on the use of the Arduino name emphasizes that the project is open to incorporating work by others into the official product.^[20] Several Arduino-compatible products commercially released have avoided the "Arduino" name by using "-duino" name variants.^[21]

• Xoscillo: open-source oscilloscope^[22]
• Scientific equipment^[23]
• Arduinome: a MIDI controller device that mimics the Monome
• OBDuino: a trip computer that uses the on-board diagnostics interface found in most modern cars
• Ardupilot: drone software / hardware
• ArduinoPhone^[24]
• GertDuino, an Arduino mate for the Raspberry Pi^[25]
• Water quality testing platform^[26]

The Arduino project received an honorary mention in the Digital Communities category at the 2006 Prix Ars Electronica.^[27]

When the Arduino project started, the five co-founders created a company that owned all the Arduino associated trademarks. The manufacture and sale of the boards was done by sell boards, Arduino would get a royalty from them. In the founding bylaws of the company, it was specified that each of the five founders was to transfer ownership of the Arduino brand to the newly formed company. At the end of 2008, Gianluca Martino’s company, Smart Projects, registered the Arduino trademark in Italy and kept this a secret from the other co-founders for about two years. This was brought to light when the Arduino company tried to register the trademark in other areas of the world (they originally registered in the US), and discovered it was already registered in Italy. Negotiations with Gianluca and his company to bring the trademark under control of the original Arduino company were not successful, and in 2014, Smart Projects began refusing to pay royalties. Smart Projects appointed a new CEO, Mr. Musto, who renamed the company to Arduino SRL and created a website named Arduino.org, copying the graphics and layout of the original Arduino.cc. This resulted in a rift in the Arduino development team, and although all Arduino boards are still available to consumers, and the designs are open source, the implications of this are uncertain.^[28][29][30]

• List of Arduino boards and compatible systems
• Comparison of single-board computers

• Getting Started with Arduino; Massimo Banzi, Michael Shiloh; 262 pages; 2014; ISBN 1-4493-6333-4.
• Arduino For Dummies; John Nussey; 446 pages; 2013; ISBN 978-1118446379.
• Programming Arduino Next Steps: Going Further with Sketches; Simon Monk; 2013; ISBN 978-0071830256.
• Exploring Arduino: Tools and Techniques for Engineering Wizardry; Jeremy Blum; 384 pages; 2013; ISBN 978-1118549360.
• Arduino Workshop: A Hands-On Introduction with 65 Projects; John Boxall; 392 pages; 2013; ISBN 978-1593274481.
• Beginning C for Arduino: Learn C Programming for the Arduino and Compatible Microcontrollers; Jack Purdum; 280 pages; 2012; ISBN 978-1430247760.
• Programming Arduino: Getting Started With Sketches; Monk Simon; 162 pages; 2011; ISBN 978-0071784221.
• Make: Electronics (Learning by Discovery); Charles Platt; 352 pages; 2009; ISBN 978-0596153748.

Wikimedia Commons has media related to Arduino (hardware).

• Official website
• Arduino The Documentary at IMDb, Vimeo
• Documentary about Arduino, Wired Magazine (Italian with English subtitles)
• How to install additional Arduino libraries
• Arduino cheat sheets
• An online platform and collaboration platform for Arduino users
• Examples of various Arduino projects
• Arduino Board Pinout Diagrams: Due, Esplora, Leonardo, Mega, Micro, Mini, Nano, Uno
• Evolution tree for Arduino
• Massimo Banzi interviewed on the TV show Triangulation on the TWiT.tv network
• Massimo Banzi interviewed on the TV show FLOSS weekly on the TWiT.tv network
• Arduino Stack Exchange, questions and answers