The Leonardo is Arduino’s first development board to use one microcontroller with built-in USB. Using the ATmega32U4 as its sole microcontroller allows it to be cheaper and simpler. Also, because the 32U4 is handling the USB directly, code libraries are available which allow the board to emulate a computer keyboard, mouse, and more using the USB-HID protocol!
Features:
ATmega32u4 Microcontroller
Input Voltage: 7-12V
20 Digital I/O Pins
7 PWM Channels
12 ADCs
16MHz Clock Speed
32 KB Flash Memory