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First Arduino Board, late 2005

Arduino logo

Arduino is a single-board microcontroller designed to make the process of using electronics in multidisciplinary projects more accessible. The hardware consists of a simple open source hardware board designed around an 8-bit Atmel AVR microcontroller, though a new model has been designed around a 32-bit Atmel ARM. The software consists of a standard programming language compiler and a boot loader that executes on the microcontroller.

Arduino boards can be purchased pre-assembled or as do-it-yourself kits. Hardware design information is available for those who would like to assemble an Arduino by hand. It was estimated in mid-2011 that over 300,000 official Arduinos had been commercially produced at that point.^[1]

History [edit]

In 2005 a project was initiated to make a device for controlling student-built interactive design projects that was less expensive than other prototyping systems available at the time. Founders Massimo Banzi and David Cuartielles named the project after Arduin of Ivrea^[2] and began producing boards in a small factory located in Ivrea, a town in the Province of Turin in the Piedmont region of northwestern Italy — the same region as the computer company Olivetti.^[3]

The Arduino project is a fork of the open source Wiring platform^[4] and is programmed using a Wiring-based language (syntax and libraries), similar to C++ with some slight simplifications and modifications, and a Processing-based integrated development environment (IDE).

Arduino was built around the Wiring project of Hernando Barragan. Wiring was Hernando's thesis project at the Interaction Design Institute Ivrea. It was intended to be an electronic version of Processing that used our programming environment and was patterned after the Processing syntax. It was supervised by myself and Massimo Banzi, an Arduino founder. I don't think Arduino would exist without Wiring and I don't think Wiring would exist without Processing. And I know Processing would certainly not exist without Design By Numbers and John Maeda.

—Casey Reas, Interview by Daniel Shiffman^[4]

In September 2006, the Arduino Mini was announced.^[5]

In October 2008, the Arduino Duemilanove was announced. It was initially based on the Atmel ATmega168, then later shipping with the ATmega328.^[5]

In March 2009, the Arduino Mega was announced. It is based on the Atmel ATmega1280.^[5]

As of May 2011^[update], more than 300,000 Arduino units were in use around the world.^[6]

In July 2012, the Arduino Leonardo was announced. It is based on the Atmel ATmega32u4. ^[7]

In October 2012, the Arduino Due was announced. It is based on the Atmel SAM3X8E, which has an ARM Cortex-M3 core.^[8]

In November 2012, the Arduino Micro was announced. It is based on the Atmel ATmega32u4.^[9]

In May 2013, the Arduino Robot was announced. It is based on the Atmel ATmega32u4 and is the first official Arduino on wheels.^[10]

In May 2013, the Arduino Yún was announced. It is based on the Atmel ATmega32u4 and on the Atheros AR9331, and is the first wifi product combining Arduino with Linux.^[11]

Hardware [edit]

An official Arduino Uno with descriptions of the I/O locations

A 3rd-party Arduino board with a RS-232 serial interface (upper left) and an Atmel ATmega8 microcontroller chip (black, lower right); the 14 digital I/O pins are located at the top and the six analog input pins at the lower right.

An Arduino board consists of an Atmel 8-bit AVR microcontroller with complementary components to facilitate programming and incorporation into other circuits. An important aspect of the Arduino is the standard way that connectors are exposed, allowing the CPU board to be connected 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, allowing many shields to 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.

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 simple 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. These pins are on the top of the board, via female 0.1 inch 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 to be plugged into solderless breadboards.

There are a great many Arduino-compatible and Arduino-derived boards. Some are functionally equivalent to an Arduino and may be used interchangeably. Many are the basic Arduino with the addition of commonplace 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 permitting the continued use of Shields, sometimes not. Some variants use completely different processors, with varying levels of compatibility.

Official boards [edit]

The original Arduino hardware is manufactured by the Italian company Smart Projects.^[12] Some Arduino-branded boards have been designed by the American company SparkFun Electronics.^[13]

Sixteen versions of the Arduino hardware have been commercially produced to date:

1. The Serial Arduino, programmed with a DE-9 serial connection and using an ATmega8
2. The Arduino Extreme, with a USB interface for programming and using an ATmega8
3. The Arduino Mini, a miniature version of the Arduino using a surface-mounted ATmega168
4. The Arduino Nano, an even smaller, USB powered version of the Arduino using a surface-mounted ATmega168 (ATmega328 for newer version)
5. The LilyPad Arduino, a minimalist design for wearable applications and E-textiles using a surface-mounted ATmega328
6. The Arduino NG, with a USB interface for programming and using an ATmega8
7. The Arduino NG plus, with a USB interface for programming and using an ATmega168
8. The Arduino Bluetooth, with a Bluetooth interface for programming using an ATmega168
9. The Arduino Diecimila, with a USB interface and utilizes an ATmega168 in a DIP28 package (pictured)
10. The Arduino Duemilanove ("2009"), using the ATmega168 (ATmega328 for newer version) and powered via USB/DC power, switching automatically
11. The Arduino Mega, using a surface-mounted ATmega1280 for additional I/O and memory.^[14]
12. The Arduino Uno, uses the same ATmega328 as late-model Duemilanove, but whereas the Duemilanove used an FTDI chipset for USB, the Uno uses an ATmega8U2 programmed as a serial converter.
13. The Arduino Mega2560, uses a surface-mounted ATmega2560, bringing the total memory to 256 kB. It also incorporates the new ATmega8U2 (ATmega16U2 in revision 3) USB chipset.
14. The Arduino Leonardo, with an ATmega32U4 chip that eliminates the need for USB connection and can be used as a virtual keyboard or mouse. It was released at the Maker Faire Bay Area 2012.
15. The Arduino Esplora, resembling a video game controller, with a joystick and built-in sensors for sound, light, temperature, and acceleration.
16. The Arduino Due is a microcontroller board based on the Atmel SAM3X8E ARM Cortex-M3 CPU. It is the first Arduino board based on a 32-bit ARM core microcontroller.^[15][8]

• Example Arduino boards
• 

  Arduino Diecimila

• 

  Arduino Duemilanove (rev 2009b)

• 

  Arduino UNO

• 

  Arduino Leonardo

• 

  Arduino Mega

• 

  Arduino Nano

• 

  Arduino Due (ARM-based)

• 

  LilyPad Arduino (rev 2007)

Shields [edit]

Arduino and Arduino-compatible boards make use of shields, printed circuit expansion boards that plug into the normally supplied Arduino pin-headers. Shields can provide motor controls, GPS, ethernet, LCD display, or breadboarding (prototyping). A number of shields can also be made DIY.^[16][17][18]

• 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 SD slot and Real-Time Clock chip

Software [edit]

Arduino Software IDE

A screenshot of the Arduino IDE showing the "Blink" program, a simple beginner program
Developer(s)	Arduino Software
Stable release	1.0.4 / March 11, 2013 (2013-03-11)[19]
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 is derived 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. There is typically no need to edit makefiles or run programs on a command-line interface.^{[citation needed]} A program or code written for Arduino is called a sketch.^[20]

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. Users only need define two functions to make a runnable 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:^[21]

The integrated pin 13 LED

#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.^[21] 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.^[22][23]

Development [edit]

The Motoruino is a third-party board kit that can be assembled by a hobbyist

The core Arduino developer team is composed of Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino, David Mellis and Nicholas Zambetti. Massimo Banzi was interviewed on the March 21st, 2009 episode (Episode 61) of FLOSS Weekly on the TWiT.tv network, in which he discussed the history and goals of the Arduino project.^[24] He also gave a talk at TEDGlobal 2012 Conference, where he outlined various uses of Arduino boards around the world.^[25]

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.^[26]

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.^[27] Several Arduino-compatible products commercially released have avoided the "Arduino" name by using "-duino" name variants.^[28]

Applications [edit]

This section requires expansion. (January 2013)

• Xoscillo: open-source oscilloscope^[29]
• Scientific equipment^[30]
• 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
• The Humane Reader and Humane PC from Humane Informatics: low-cost electronic devices with TV-out that can hold a five thousand book library (e.g. offline Wikipedia compilations) on a microSD card
• Ardupilot: drone software / hardware

Reception [edit]

The Arduino project received an honorary mention in the Digital Communities category at the 2006 Prix Ars Electronica.^[31][32]

See also [edit]

	Free software portal
	Electronics portal

• ARM express
• BASIC Stamp
• Fritzing
• Gumstix
• ioBridge
• Make Controller Kit
• Maximite
• mbed microcontroller
• Minibloq
• Netduino
• OOPic
• Parallax Propeller
• PICAXE
• Raspberry Pi
• Simplecortex
• Tinkerforge

References [edit]

External links [edit]

Wikimedia Commons has media related to: Arduino

• Official website
• Arduino The Documentary at the Internet Movie Database, YouTube, Vimeo
• Documentary about Arduino, Wired Magazine (in Italian)
• Arduino Shield list
• Arduino RTOS list
• How to install additional Arduino libraries?
• Arduino Cheat Sheet
• Arduino Board Pinout Diagrams: Due, Esplora, Leonardo, Mega, Micro, Mini, Uno