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