It’s a significant update. The Arduino UNO and Arduino Mega 2560 update the Duemilanove and Mega respectively. They now use an ATMega8U2 instead of an FTDI USB to serial converter chip.

If you're on the hunt for the perfect board, then you've probably come across the Uno and Nano. They're two of the most frequently used Arduino variations, but they serve different purposes.

The chip gets programmed in an Arduino Uno and then transplanted into the calculator, a neat trick if you don’t have a dedicated programmer handy. Given how cheap Arduino clones can be had ...