Arduino Uno

Arduino Uno is a microcontroller board based on the ATmega328 (datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analogue 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. The Uno differs from all preceding boards in that it does not use the FTDI USB-to-serial driver chip. Instead, it features the Atmega16U2 (Atmega8U2 up to version R2) programmed as a USB-to-serial converter.

Microcontroller ATmega328P
Operating voltage of 5V
Maximum supply voltage 6 to 20V
Digital I/O pins 14 (of which 6 provide PWM output)
DC current per I/O pin 40mA
DC current for 3.3V pin 50mA
Flash memory16KB of which 2KB is used by boot loader
SRAM 2KB, EEPROM 1KB
Clock speed 16MHz
Can be powered via the USB connection or with an external power supply