This board added SDA and SCL pins that are near to the AREF pin and two other new pins placed near to the RESET pin, the IOREF that allow the shields to adapt to the voltage provided from the board. 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. It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button.

' Arduino Uno' is a microcontroller board based on the ATmega328. This makes it really easy to figure out where to connect sensors, or to identify which side is Analog (blue) or Digital (green). You could remove it to update or reprogram the chip's firmware, or even to place it on a finished, more compact project. The cool thing about our new DFRduino microcontroller is that the headers use different colors to feature I/O ports of different types:

An added bonus is that our DFRduino is still using the DIP package AVR Chip. This board features the ATmega16U2 programmed as a USB-to-serial converter. The open-source IDE can be downloaded for free (currently for Mac OS X, Windows, and Linux). Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. This environment implements the Processing / Wiring language. It is a simple microcontroller board fully compatible with Arduino UNO R3 and Arduino IDE open-source development environment. DFRduino Uno V3.0 from DFRobot is a physical world computing board of small size for academics or development.

Datasheet of arduino uno