After Arduino UNO, the most popular board in the Arduino line-up is
probably the Arduino Nano. Both UNO and Nano are based on ATmega328P
Microcontroller but Nano is significantly smaller in size compared to
UNO.
Front and Back view of Arduino Nano Board
Despite the size, Arduino Nano packs in more or less the same
features as UNO. If you compare UNO and Nano, then Nano lacks the DC
Power Jack and contains a mini-B type USB connector. Other than that
Nano is very similar to UNO in terms of functionality.
The Nano board is designed in such a way that the pins are breadboard
friendly so that you can easily mount it on one for your DIY projects.
Overall, the Arduino Nano is a very good alternative to the mighty
Arduino UNO and is available at a lower price. Personally speaking, I
suggest Arduino Nano over UNO as it is cheaper, breadboard friendly,
small in size and has couple of more pins (digital and analog IO) than
UNO.
Arduino Nano Board Layout
The following image shows the layout of a typical Arduino nano board.
As you can see from the previous image, there are a couple of
components on the bottom side of the board as well (5V Regulator and
USB-to-Serial Converter IC are the main ones).
Layout of Arduino Nano Board
As you can notice, the Type-B USB connector from Arduino UNO is
replaced with mini-B type connector. Also, there is no 2.1 mm DC jack to
provide external power supply. Apart from that, the layout of Arduino
Nano is very much self-explanatory.
.
Technical Specifications of Arduino Nano
As Arduino Nano is also based on ATmega328P Microcontroller, the
technical specifications are similar to that of UNO. But none the less,
let me give you a brief overview about some important specifications of
Arduino Nano.





MCU

ATmega328P


Architecture

AVR




Operating Voltage

5V


Input Voltage

7V – 12V




Clock Speed

16 MHz


Flash Memory

32 KB (2 KB of this used by bootloader)




SRAM

2 KB


EEPROM

1 KB




Digital IO Pins

22 (of which 6 can produce PWM)


Analog Input Pins

8