The Arduino Uno, the successor to the Arduino Duemilanove, is a microcontroller board based on a removable, dual-inline-package (DIP) ATmega328 AVR microcontroller. It has 20 digital input/output pins (of which 6 can be used as PWM outputs and 6 can be used as analog inputs), a 16 MHz resonator, a USB connection, a power jack, an in-circuit system programming (ICSP) header, and a reset button. The Arduino has an extensive support community, which makes it a very easy way to get started working with embedded electronics.
 
 
General specifications
Processor:
ATmega328 @ 16 MHz
RAM size:
2048 bytes
Program memory size:
31.5 Kbytes
Motor channels:
0
User I/O lines:
201
Max current on a single I/O:
40 mA
Minimum operating voltage:
7 V
Maximum operating voltage:
12 V
Reverse voltage protection?:
N
External programmer required?:
N2