3Pcs R3 ATmega16U2 AVR USB Development Main Board

is an open-source physical computing platform based on a simple i/o board and a development environment that implements theProcessing/Wiring language. can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing, MaxMSP). The open-source IDE can be downloaded for free (currently for Mac OS X, Windows, and Linux).
This is the new Tosduino Uno R3. In addition to all the features of the previous board, the Uno R3 now uses an ATmega16U2 instead of the ATmega8U2 chip. This allows for faster transfer rates, no drivers needed for Linux or Mac (inf file for Windows is needed), and the ability to have the Uno show up as a keyboard, mouse, joystick, etc.

Note: 

The TOSduino Uno R3 requires the 1.0 drivers folder in order to install properly on some computers. We have tested and confirmed that the R3 can be programmed in older versions of the IDE. However, the first time using the R3 on a new computer, you will need to have 1.0 installed on that machine.
The small chip is ATmega16U2, the 28 pin DIP socket chip is ATmega328-pu.

Performance description:

Digital I / O digital input / output terminal: 0 to 13.
Analog I / O Analog inputs / outputs: 0 to 5.
Support ISP download function.
Input voltage: No external power supply when connected to the computer USB, external power supply 5V ~ 9V DC voltage input.
Output voltage: 5V / 3.3V DC.
Using Atmega328 microprocessor controller.

Package included:

3 x UNO R3
3 x USB cable