Arduino Nano is a surface mount breadboard embedded version with integrated USB. It is a smallest, complete, and breadboard friendly. It has everything that Diecimila/Duemilanove has (electrically) with more analog input pins and onboard +5V AREF jumper. Physically, it is missing power jack. The Nano is automatically sense and switch to the higher potential source of power, there is no need for the power select jumper.

Specifications:

• Microcontroller: Atmel ATmega328
• Operating Voltage (logic level): 5 V
• Input Voltage (recommended): 7-12 V
• Input Voltage (limits): 6-20 V
• Digital I/O Pins: 14 (of which 6 provide PWM output)
• Analog Input Pins: 8
• DC Current per I/O Pin: 40 mA
• Flash Memory: 32 KB (of which 2KB used by bootloader)
• SRAM: 2 KB
• EEPROM: 1 KB
• Clock Speed: 16 MHz
• Dimensions:45x18x18mm (with Pin headers)