Most of us are familiar with the Arduino ... pin layout (Arduino shields likely won’t fit) and more I/Os than the ATmegas have. Sure, it’s not as practical as an actual Arduino Uno, but ...

The Leonardo sports a new pin layout, dubbed R3 (which the Uno has also been updated with), that will become standard across all Arduino boards.

Software scalability is also supported on the new board, allowing easy upgrades for projects made with UNO R3 or Leonardo. Requests from the Arduino community ... additional pins to turn off ...

and additional SDA and SCL pins. Since the discontinuation of the original and Rev2 boards, the Rev3 has become the face of the Uno family and the Arduino brand in general. In fact, it's ...

Arduino will continue to make available the Arduino UNO R3 and provide support to all those Arduino enthusiasts that have and would like to create projects using its 8-bit AVR microcontroller.

The new UNO R4 board comes in two versions, with and without Wi-Fi connectivity, and maintains the form factor, shield compatibility and 5V power supply of the UNO R3. The UNO R4 with its 96 red LED ...