There’s a new Arduino in town, this time designed in conjunction with Adafruit. It’s the Arduino Micro, a very neat little board designed for breadboard use.
Ostensibly an upgrade of the long in the tooth Arduino Nano, the new Micro takes all the best features of the new Arduino Leonardo and shrinks them down to a convenient stick of gum-sized package. It’s powered by the ATmega32u4 microcontroller, and with a MicroUSB port is able to emulate keyboards, mice and other USB input devices.
Of course with any microcontroller dev board, comparisons must be drawn between the Arduino Micro and the very popular Teensy USB dev board. Like the Teensy boards (and the new Arduino Leonardo), the Micro is able to function as a USB keyboard or mouse. The Teensys, though, is loaded with LUFA making it able to emulate just about anything from mice, USB audio devices, and MIDI synths.