Arduino is an open-source electronics prototyping platform based on flexible, easy-to-use hardware and software. It's intended for artists, designers, hobbyists, and anyone interested in creating interactive objects or environments.
Arduino can sense the environment by receiving input from a variety of sensors and can affect its surroundings by controlling lights, motors, and other actuators. The microcontroller on the board is programmed using the Arduino programming language (based on Wiring) and the Arduino development environment (based on Processing). Arduino projects can be stand-alone or they can communicate with software running on a computer (e.g. Flash, Processing, MaxMSP).
Arduino Uno R3 & Arduino Uno SMD - The Arduino Uno Revision 3 is a microcontroller board based on the ATmega328. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz ceramic resonator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started.
Arduino Due - 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. It has 54 digital input/output pins (of which 12 can be used as PWM outputs), 12 analog inputs, 4 UARTs (hardware serial ports), a 84 MHz clock, an USB OTG capable connection, 2 DAC (digital to analog), 2 TWI, a power jack, an SPI header, a JTAG header, a reset button and an erase button.The board contains everything needed to support the microcontroller; simply connect it to a computer with a micro-USB cable or power it with a AC-to-DC adapter or battery to get started. The Due is compatible with all Arduino shields that work at 3.3V and are compliant with the 1.0 Arduino pinout.
Arduino Esplora - The Arduino Esplora is a microcontroller board derived from the Arduino Leonardo. The Esplora differs from all preceding Arduino boards in that it provides a number of built-in, ready-to-use setof onboard sensors for interaction. It's designed for people who want to get up and running with Arduino without having to learn about the electronics first. The Esplora has onboard sound and light outputs, and several input sensors, including a joystick, a slider, a temperature sensor, an accelerometer, a microphone, and a light sensor. It also has the potential to expand its capabilities with two Tinkerkit input and output connectors, and a socket for a color TFT LCD screen.
Arduino Leonardo - The Arduino Leonardo is a microcontroller board based on the ATmega32u4 (datasheet). It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Leonardo differs from all preceding boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Leonardo to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
Arduino Mega 2560 R3 - The Revision 3 of the Mega released with the Uno, this version features the Atmega2560, which has twice the memory, and uses the ATMega 8U2 for USB-to-serial communication.
Nano - A compact board designed for breadboard use, the Nano connects to the computer using a USB Mini-B cable.
LilyPad - Designed for wearable application, this board can be sewn onto fabric, and is a stylish purple.
Fio - Designed for wireless applications. It includes a socket for an XBee radio, a connector for a LiPo battery, and integrated battery charging circuitry.
Bluetooth - The Arduino BT contains a bluetooth module that allows for wireless communication and programming. It is compatible with Arduino shields.
Pro - This board is designed for advanced users who want to leave a board embedded in a project: it's cheaper than a Diecimila and easily powered by a battery, but requires additional components and assembly.
Mini - This is the smallest Arduino board. It works well in a breadboard or for applications in which space is at a premium. It connects to the computer using the Mini USB Adapter.
Pro Mini - Like the Pro, the Pro Mini is designed for advanced users requiring a low-cost, small board and willing to do some extra work.
Mini USB Adapter - This board converts a USB connection into 5 volt, GND, TX and RX lines that you can connect to the Arduino Mini or other microcontroller.
Serial - It's a basic board that uses RS232 as an interface to a computer for programming or communication. This board is easy to assemble even as a learning exercise. (including Schematics and CAD Files)
Arduino ADK - This board is based on the ATmega2560. It has a USB host interface to connect with Android based phones, based on the MAX3421e IC. It has 54 digital input/output pins (of which 14 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.The ADK is based on the Mega 2560.Similar to the Mega 2560 and Uno, it features an ATmega8U2 programmed as a USB-to-serial converter.
Revision 2 of the MegaADK board has a resistor pulling the 8U2 HWB line to ground, making it easier to put into DFU mode.
Shields are boards to be mounted on top of the Arduino board and that extend the functionality of Arduino to control different devices, acquire data, etc.
XBee Shield - This shield allows multiple Arduino boards to communicate wirelessly over distances up to 100 feet (indoors) or 300 feet (outdoors) using the Maxstream Xbee Zigbee module.
Motor Shield - This shield allows an Arduino board to control DC motors and read encoders.
Ethernet Shield - This shield allows an Arduino board to connect to the internet.