Get ready for experimenting & learning with Jameco's stock of the Arduino Leonardo. The Leonardo is Arduino's first development board to use one microcontroller with built-in USB. This popular microcontroller board is based on the ATmega32u4 and differs from all preceding boards in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Leonardo to appear to a connected computer as a mouse and keyboard, in addition to a virtual serial/port.