Arduino Nano is basically a smaller version of Arduino board.
There are 2 type of Arduino Nano at the time of writing:
- Arduino Nano 3.0 (ATmega328)
- Arduino Nano 2.3 (ATmega168)
More detail can be found here at
official site
The one I have here is v3. The obvious difference between an Uno and nano board I notice immediately is: nano board pins is facing towards bottom, where you normally mount it onto a small breadboard to use it.
![20140918_232845](http://tech.yeesiang.com/wp-content/uploads/2014/09/20140918_232845-1024x768.jpg)
Next, all the pin sequence are different as shown in this picture.
![](http://arduino.cc/en/uploads/Main/ArduinoNanoFront_3_sm.jpg)
When uploading code from Arduino IDE, you might see some warning msg appearing at debug windows:
Sketch uses 3,010 bytes (9%) of program storage space. Maximum is 32,256 bytes.
Global variables use 203 bytes (9%) of dynamic memory, leaving 1,845 bytes for local variables. Maximum is 2,048 bytes.
It means you actually scarify the memory space in exchange for the small footprint.
So far I have used it for digital out & analog in and behave just the same with uno.