Pololu A-Star 32U4 Micro Programmable Module

The A-Star 32U4 Micro Programmable Module is a tiny programmable module featuring Atmel’s ATmega32U4 microcontroller. It packs a Micro-USB interface and 18 digital input/output pins of which 7 can be used as PWM outputs and 8 as analog inputs onto a board measuring only 1″ × 0.6″ and preloaded with an Arduino-compatible bootloader. Programmable 16 MHz Atmel ATmega32U4 AVR microcontroller; 12 Mbps native full-speed USB; Preloaded with Arduino-compatible bootloader; RAM size of 2560 bytes