Arduino is an open-source physical computing platform based on a simple i/o board and a development environment that implements theProcessing/Wiring language. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. FlashProcessingMaxMSP). The open-source IDE can bedownloaded for free (currently for Mac OS XWindowsand Linux).
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. Alsobecause the 32U4 is handling the USB directlycode libraries are available which allow the board to emulate a computer keyboardmouseand more using the USB-HID protocol!
It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs)a 16 MHz crystal oscillatora micro USB connectiona power jackan ICSP headerand 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.
Not sure which Arduino or Arduino-compatible board is right for you? Check out our Arduino Buying Guide!