We can program on Arduino UNO by using Arduino IDE (Integrated Development Environment) software. You can use the USB cable to connect Arduino UNO to your computer.

Here’s a tutorial if you get stuck. You’ll also need an Arduino-compatible microcontroller and an appropriate way to connect it to your computer (an A-to-B USB cable, micro USB, or FTDI breakout).

It's of course backwards compatible with existing Arduino add-ons, but sets itself apart with a new USB controller with lower latency and driver-free operation on Mac and Linux.

The newly released Arduino Leonardo has a few very interesting features, most notably the ability to act as a USB keyboard and mouse thanks to the new ATmega 32U4 microcontroller. This feature isn&… ...