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Arduino Uno - R3.jpg
"Arduino Uno" Revision 3
TypeSingle-board microcontroller
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Arduino Logo.svg
Arduino Uno - R3.jpg
"Arduino Uno" Revision 3
TypeSingle-board microcontroller

Arduino is a single-board microcontroller, intended to make the application of interactive objects or environments more accessible.[1] The hardware consists of an open-source hardware board designed around an 8-bit Atmel AVR microcontroller, or a 32-bit Atmel ARM. Current models feature an USB interface, 6 analog input pins, as well as 14 digital I/O pins which allow to attach various extension boards.

Introduced in 2005, it was designed to give students an inexpensive and easy way to program interactive objects. It comes with a simple integrated development environment (IDE) that runs on regular personal computers and allows to write programs for Arduino using C or C++.

The current prices of Arduino boards run around $30 and those of related "clones" as low as $9. 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,[2] and in 2013 that 700,000 official boards were in users' hands.[3]


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.[4]

A hardware thesis was contributed for a wiring design by Colombian student Hernando Barragan. After the wiring platform was complete, researchers worked to make it lighter, less expensive, and available to the open source community. The school eventually closed down, so these researchers, one of them David Cuartielles, promoted the idea.[4]

The current prices run around $30 and related "clones" as low as $9.[4][5] A simple Arduino Mini Pro[6] clone may be had from China for less than $4, post paid.[7]


An official Arduino Uno with descriptions of the I/O locations
An early Arduino board[8] 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. 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. 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 to be plugged into solderless breadboards.

There are 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.[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.


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.[11][12][13]


Arduino Software IDE
Arduino 1.0 IDE, Ubuntu 11.10.png
A screenshot of the Arduino IDE showing the "Blink" program, a simple beginner program
Developer(s)Arduino Software
Stable release1.0.5 / May 15, 2013 (2013-05-15)[14]
Preview release1.5.6-r2 Beta / February 21, 2014 (2014-02-21)
Written inJava, C and C++
Operating systemCross-platform
TypeIntegrated development environment
LicenseLGPL or GPL license

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. 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. Users only need define two functions to make a runnable cyclic executive program:

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]

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.[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]


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 network, in which he discussed the history and goals of the Arduino project.[19] He also gave a talk at TEDGlobal 2012 Conference, where he outlined various uses of Arduino boards around the world.[20]

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.[21]

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.[22] Several Arduino-compatible products commercially released have avoided the "Arduino" name by using "-duino" name variants.[23]



The Arduino project received an honorary mention in the Digital Communities category at the 2006 Prix Ars Electronica.[27][28]

See also[edit]


  1. ^ "Official slogan". Arduino Project. Retrieved 2013-12-31. 
  2. ^ "How many Arduinos are "in the wild?" About 300,000". Adafruit Industries. May 15, 2011. Retrieved 2013-05-26. 
  3. ^ "Arduino FAQ – With David Cuartielles". Malmö University. April 5, 2013. Retrieved 2014-03-24. 
  4. ^ a b c David Kushner (26 Oct 2011). "The Making of Arduino". IEEE Spectrum. 
  5. ^ "Assembling the Really Bare Bones Board (RBBB) Arduino clone". 16 Aug 2008. 
  6. ^ "Arduino Pro Mini". 
  7. ^ "eBay posting for a very cheap ArduinoPro Mini clone - there are many similar ones". March 2014. 
  8. ^ "Hardware Index". Arduino Project. Retrieved 2013-12-10. 
  9. ^ Smart Projects
  10. ^ Schmidt, M. ["Arduino: A Quick Start Guide"], Pragmatic Bookshelf, January 22, 2011, Pg. 201
  11. ^ "Arduino breadboard shield: US$10 & 10 mins".
  12. ^ Igoe, Tom (April 4, 2006). "Arduino Shields for Prototyping".
  13. ^ Jonathan Oxer. "Arduino Shield list". Retrieved 5 Nov 2013. 
  14. ^ "Arduino Software Release Notes". Arduino Project. Retrieved May 31, 2013. 
  15. ^ "Programming Arduino Getting Started with Sketches". McGraw-Hill. Nov 8, 2011. Retrieved 2013-03-28. 
  16. ^ "Using Atmel Studio for Arduino development". Retrieved 2013-01-18. 
  17. ^ "Using AVR Studio for Arduino development". Retrieved 2013-01-18. 
  18. ^ "FLOSS Weekly Episode 61 – Arduino" (audio, MP3). March 21, 2009
  19. ^ Banzi, Massimo. "How Arduino is open-sourcing imagination". TED. 
  20. ^ "The arduino source code". The arduino source code. 
  21. ^ "Policy". Retrieved 2013-01-18. 
  22. ^ "Freeduino Open Designs". Retrieved 2008-03-03. 
  23. ^ "xoscillo – A software oscilloscope that acquires data using an arduino or a parallax (more platforms to come). – Google Project Hosting". Retrieved 2013-01-18. 
  24. ^ Pearce, Joshua M. 2012. "Building Research Equipment with Free, Open-Source Hardware". Science 337 (6100): 1303–1304. (open access)
  25. ^ ArduinoPhone. (2013-07-17). Retrieved on 2013-08-04.
  26. ^ "Prix Ars Electronica 2006 – Digital Communities – ANERKENNUNGEN – listing" (in German). Retrieved 2009-02-18. 
  27. ^ "Prix Ars Electronica 2006 – Digital Communities – ANERKENNUNGEN – description" (in German). Retrieved 2009-02-18. 

External links[edit]