Arduino

For other uses, see Arduino (disambiguation).

Arduino Software

A screenshot of the Arduino IDE showing a simple example program.
Developer(s)	Arduino Software
Stable release	0015 / March 26, 2009 (2009-03-26)
Written in	Java
Operating system	Cross-platform
Type	Integrated Development Environment
License	LGPL or GPL license
Website	http://www.arduino.cc/

Arduino is a physical computing platform based on a simple I/O board and a development environment that uses the Wiring library to simplify writing C/C++ programs that run on the board. Arduino can be used to develop stand-alone interactive objects or can be connected to software running on a computer (e.g., Adobe Flash, Processing, Max/MSP, Pure Data, SuperCollider). Currently shipping versions can be purchased pre-assembled; hardware design information is available for those who would like to assemble an Arduino by hand.

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

The project began in Italy in 2005 to make a device for controlling student-built robots less expensively than other prototyping systems available at the time. The designers succeeded in making an easy-to-use platform which significantly undercut the prices of many competing products. More than 50,000 Arduino boards have shipped as of October 2008.

Platform

Hardware

An Arduino board consists of an 8-bit Atmel AVR microcontroller with complementary components to facilitate programming and incorporation into other circuits. Official Arduinos have used the megaAVR series of chips, specifically the ATmega8, ATmega168, ATmega328, and ATmega1280. A handful of other processors have been used by Arduino clones. Most boards include a 5-volt linear regulator and a 16MHz crystal oscillator (or ceramic resonator in some variants), although some designs such as the LilyPad run at 8Mhz and dispense with the onboard voltage regulator due to specific form-factor restrictions. An Arduino's microcontroller is also pre-programmed with a bootloader that simplifies uploading of programs to the on-chip flash memory, compared with other devices that typically need an external chip programmer.

At a conceptual level, all boards are programmed over an RS-232 serial connection, but the way this is implemented in hardware varies by version. Serial Arduino boards contain a simple inverter 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.

The Arduino board exposes most of the microcontroller's I/O pins for use by other circuits. The Diecimila, now superseded by the Duemilanove, for example, provides 14 digital I/O pins, 6 of which can produce PWM signals, and 6 analog inputs. These pins are available on the top of the board, via female 0.1 inch headers. Several plug-in application boards known as "shields" are also commercially available.

The Arduino-compatible Barebones and Boarduino boards provide male header pins on the underside of the board to be plugged into solderless breadboards.

Software

The Arduino IDE is a cross-platform application written in Java which is derived from the IDE made for the Processing programming language and the Wiring project. 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 the command line.

The Arduino IDE comes with a C/C++ library called "Wiring" (from the project of the same name), which makes many common input/output operations much easier. Arduino programs are written in C/C++, although users only need to define two functions in order to make a runnable program:

• setup() – a function run once at the start of a program which can be used to initialize settings, and
• loop() – a function called repeatedly until the board is powered off.

A typical first program for a microcontroller is to simply blink a light-emitting diode on and off. In the Arduino environment, the user might write a program like this:

#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
}

The above code would not be seen by the 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:

#include "WProgram.h"
#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
}

int main(void)
{
    init();

    setup();
    
    for (;;)
        loop();
        
    return 0;
}

"WProgram.h" is the main header for the Wiring library, and the main() function only makes three distinct calls: init(), defined in the library itself, and the setup() and loop() functions defined by the user.

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

Official hardware

The Arduino Diecimila

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

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

1. The Serial Arduino, programmed with a DB9 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
5. The LilyPad Arduino, a minimalist design for wearable application using a surface-mounted ATmega168
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 BT, with a Bluetooth interface for programming using an ATmega168
9. The Arduino Diecimila, with a USB interface and utilizes an Atmega168 in a DIL28 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.

Open hardware and open source

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 and the on-board library are available and released under the GPLv2 license.

Accessory hardware

A prototyping shield, mounted on an Arduino

Arduino and clones make use of shields, which are printed circuit boards which sit atop an Arduino, and plug into the normally supplied pin-headers. These are expansions to the base Arduino. There are many functions of shields, from motor controls, to breadboarding (prototyping).

Clones

While the hardware and software designs are available under copyleft licenses, the developers have expressed a desire that the name "Arduino" (or derivatives thereof) 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.

As a result of the protected naming conventions of the Arduino, a group of Arduino users forked (in an extended meaning of the word) the Arduino Diecimila, releasing an equivalent board called Freeduino. The name Freeduino is not trademarked and is free to use for any use.

Several Arduino-compatible products avoid the "Arduino" name by using 'duino' name variants. They have been commercially released by other manufacturers.

Shield-compatible clones

The following boards are fully or almost fully compatible with both the Arduino hardware and software, including being able to accept "shield" daughterboards.

• The "Freeduino SB", manufactured and sold as a mini-kit by Solarbotics.
• The "Freeduino MaxSerial", a board with a standard DB9 serial port, manufactured and sold assembled or as a kit by Fundamental Logic.
• The "Freeduino Through-Hole", a board that avoids surface-mount soldering, manufactured and sold as a kit by NKC Electronics.
• The "Illuminato", a board which uses an ATMega645 instead of an ATMega168. This provides 64K of flash, 4K of RAM and 32 general IO pins. Hardware and firmware are open source. The board is designed to look svelte and has 10 LEDs that can be controlled using a "hidden" instruction. It was developed by Liquidware.
• The "metaboard", a board that is designed to have a very low complexity and thus a very low price. Hardware and firmware are open source. It was developed by Metalab, a hackerspace in Vienna.
• The "Seeeduino", derived from the Diecimila.
• The "eJackino", kit by CQ publisher in JAPAN. Similar to Seeeduino, eJackino can use Univarsal boards as Shields. On Back side, there is a "Akihabara station" silk, just like Italia on Arduino.

Bootloader-compatible clones

These boards are compatible with the Arduino software but do not accept shields. They have different connections to the I/O pins, such as a series of pins on the underside of the board for use with breadboards for easy prototyping, or more specific connectors.

• The "Boarduino" - an inexpensive Diecimila clone made for breadboarding, produced by Adafruit.
• The "Bare Bones Board" (BBB) and "Really Bare Bones Board" (RBBB) by Modern Device - compact inexpensive clones suitable for breadboarding.
• The "iDuino", a USB board for breadboarding, manufactured and sold as a kit by Fundamental Logic.
• The "Sanguino" - An open source enhanced Ardiuno clone which uses an ATMega644P instead of an ATMega168. This provides 64K of flash, 4K of RAM and 32 general IO pins in a 40 pin DIP device. It was developed with the RepRap Project in mind.
• The "LEDuino", a board with enhanced I²C, DCC decoder and CAN-bus interfaces. Manufactured using surface mount and sold assembled by Siliconrailway.
• The "Stickduino", similar to a usb key.
• The "Roboduino", designed for robotics. All of its connections have neighboring power buses into which servos and sensors can easily be plugged. Additional headers for power and serial communication are also provided. It was developed by Curious Inventor, L.L.C.

Non-ATmega boards

The following boards accept Arduino "shield" daughter boards but do not use ATmega micro-controllers. Thus they are incompatible with the Arduino environment.

• The "ARMmitePRO", an ARM-based shield-compatible board from Coridium, programmable in BASIC or C.
• The "Cortino", a development system for the 32-bit ARM Cortex M3 Microprocessor.

Development team

The core Arduino developer team is composed of Massimo Banzi, David Cuartielles, Tom Igoe, Gianluca Martino, David Mellis and Nicholas Zambetti.

See also

• Make Controller Kit
• BASIC Stamp
• OOPic
• PICAXE
• Parallax Propeller
• Processing
• Fritzing

External links

• Arduino project main page: http://www.arduino.cc/
• Arduino wiki, aka the Playground
• Comprehensive Arduino Tutorial
• Make Magazine article on the Arduino
• "Wiring" software project: http://wiring.org.co/
• Arduino photos on Flickr: http://www.flickr.com/photos/tags/arduino/
• Arduino tutorial – broken into several lessons with photographs and suggestions for appropriate tools for beginners.
• Introduction to the Arduino - Weekend Project Podcast
• Sheepdog Software's Introduction to Arduino: "Getting Started" pages and sequenced programming tutorials, with help on hardware.
• Arduino tutorial – in portuguese, but with source codes and videos.
• The largest selection of Arduino related products - Good starting point for building Arduino based projects