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Arduino: Introduction & TYPES

If you are new to Arduino, just go through the page and successive pages.  Just have a glance on the differences in the Arduino Boards.  Initially, it is not possible to have full idea about all Arduino boards.  Just read on . . .

Arduino is a brand name and available as development boards for quick connection and programming.  Many varieties of development boards are available from Arduino.  Almost  all Arduino boards use one AVR micro-controller IC (or chip) on its board, with boot-loader program (pre-loaded by default).  In addition to the micro-controller, the board is generally equipped with a voltage regulator IC(s) and USB interface IC.  The USB interface IC is useful to UPLOAD the program code and communicate external equipment using USB port (like PC).

Now (for the time being), our discussion is made limited to Make-at-Home projects.  We are explaining about the Arduino boards, which are easily available and easily used for our projects.  Normally,  Arduino boards operates between 7VDC to 12VDC (input at Vin pin) and a crystal is used for system frequency (for on-board micro-controller).  The voltage regulator IC(s) convert input voltage available through DC jack, to 5VDC & 3.3VDC output voltages, which are available on the Arduino board.  You may also directly connect 5VDC supply to 5V pin on Arduino board instead of 7 to 12VDC from DC jack. (refer images below)

The basic data about the Arduino boards, which are frequently used in our projects, is listed below for quick reference.  The pin outs are labelled and power supply pins are marked in red and blue colours for easy identification.  

Arduino UNO:

Arduino UNO  is one of the highly used Arduino boards.  Most of the Arduino starters, use Arduino Uno board initially for learning.  The ATMEGA328P micro-controller is used for Arduino Uno board.

Small differences are observed in Arduino Boards, which are shown here. 


In case of PDIP, you may replace the micro controller (ATMEGA328P) and upload BOOT LOADER to the new micro-controller.

In case of CH340 IC is used for USB to Serial converter, then suitable driver has to be installed on your computer.


The main pin-outs of Arduino UNO  is shown below for easy identification and under standing.  So, some pins are connected internally to work as one or more than one function.  You have to write suitable code to control the particular pin for the required functionality.  It is a general practice that the code written for Arduino is called as SKETCH.  

The Arduino Uno board is programmed through USB type-B port (normally available for USB printers) and a separate DC power supply jack is available in addition to Vin pin.


Arduino NANO:

Arduino NANO board is bread-board friendly pin-outs, smaller in size and frequently used for Arduino projects. Due to its compactness with most of the required features and low-cost, it is loved by Arduino programmers. For Arduino Nano also, ATMEGA328P micro-controller is used.

The main differences w.r.t. Arduino Uno are:

1) mini USB socket for programming.

2) two extra ADC channels A6 & A7

3) positions of pin nos 0 & 1 are reversed

4) No DC jack is available. use Vin only for power input.


Arduino MEGA:

Arduino MEGA board is bigger in size and frequently used for Arduino projects, where more number of digital pins are required. Almost all features and pin-outs will match with Arduino Uno, where as extra pins are available for Arduino Mega.  You may replace Arduino Uno with Arduino Mega, but, reverse may not be possible, if the program uses the extra pins.  The ATMEGA2560 micro-controller is used for Arduino Mega board.


You may expect explanation about some more types of Arduino boards in future . . .

SUCCESS is, when your SIGNATURE changes to Autograph.

– Dr. A.P.J Abdul Kalam

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