Introduction to Arduino

What is Arduino

Arduino is an Open Source Microcontroller (or a prototyping) Board that lets you use various sensors and modules (Bluetooth HC-05 or Wi-Fi Module ESP8266 ) to use with an Arduino microcontroller. It allows you to control various digital or analog devices via your commands. Likewise, you can control motors, actuators or LED lights. You can do all that with a single palm-size board. And, its instructions (code) is similar to C whereas the Arduino library is written in the C++ language.

With this, you can create a model that interacts with the real world. For instance, you can send data from/to an Android Phone via Bluetooth Module, or you can read an environment's temperature from a temperature-module. Further, you can process the data to a computer or on the internet. There are so many innovative things you can do with a single-board Arduino Uno.

Co-Founder: Massimo Banzi

Types of Arduino

Since it's Open Source Hardware and anyone can clone it in their own preferred way. Among all, we have a few popular ones as in the following:

  • Arduino UNO (fundamental and very basic).
  • Arduino Mega (advanced in terms of memory and functionality).
  • Arduino Nano (most tiny in size).
  • Arduino YEN (advanced).
  • Arduino LilyPad (tiny in size).

Figure: Arduino Mega then, Arduino UNO and last we have Arduino Nano.

And, it's always recommended to start with an Arduino UNO microcontroller.


  • It's an Open Source Project.
  • Arduino and your computer interface with a USB A to B cable. The chip on the Arduino board treats the USB as a Serial Port. Though, your computer detects it as a virtual serial device that is communicating through a Serial Communication.
  • There is a simple built-in power regulater. Since using an external voltage supply you can 12volts whereas it supplys either 3.3 Volts or 5 Volts.
  • We have an ATmega328 chip at the heart of the microcontroller.
  • The clock speed of the Arduino UNO is 16 MHz. Not the fastest, but that much is enough to control most modules.
  • It has 32KB of flash memory to store your code.
  • Arduino UNO has 13 digital pins to connect digital devices or external modules. Whereas, it has 6 analog pins to connect analog devices.
  • There is an on-board LED in front of pin 13.
  • Besides the USB port, there is a small push-button to reset the program on a chip.

Arduino IDE

Download link

Contribute to the Arduino Software.

Just below the menu bar, we have a few button that are most used.

  1. It's a VERIFY button that debugs your code and checks whether it's correct or not.

  2. After compilation, we need to upload that code to an Arduino UNO for execution. So, we have this button to upload.

  3. Finally, we have New, Open and Save that you can find in File also.
  4. Next, we have some sample code that is essentially good when you are new to Arduino programming. And, that you will get in File > Examples.

  5. Then, we have another feature in Tools where you keep your eyes always open while working with Arduino.

Set the Arduino UNO in your board section and choose the correct COM port of Arduino. I then have something like this:


Like all programming languages, it has its own recipe to code that is quite similar to the C language. That's the reason why most of the libraries are written in C++.

So, in Arduino code we will have two definite functions or method, void setup() and void loop().

Where the setup() method is designed to assign the PIN numbers and initialization part, what is to be done before the microcontroller begins executing. Here, we just fix or setup our Arduino.Next, we have the loop() method that actually is the coding part. And it continues to execute until you turn your Arduino off. Most of the conditions, logic and decision-making statements are written in this block.

In a few words, If I must say

Setup() is similar to a function prototype declaration in the C language where you suggest what kind of data you are expecting. While, loop() Is the actual method where you define all the logic and conditions.

How to Light Up a LED

Pre-requite stuff

  • 3mm LED
  • Arduino UNO
  • USB A-B Cable



  1. First, connect your LEDs (+ve port) to Digital Pin 12 and the other end to the Ground (GND) of the Arduino.
  2. Connect your Arduino to the Computer's USB cable and wait until it finds the COM port.
  3. Write your code (or, sketch what people say).
  4. Then, verify your code and upload to the Arduino.

Note: an LED has two legs; the longer leg is always positive whereas the shorter leg is negative.

The code will be as in the following:

  1. // LIGHT UP LED  
  2. int LED = 12; // PIN 12  
  3. void setup()   
  4. {  
  5.     pinMode(LED, OUTPUT);  
  6. }  
  7. void loop()   
  8. {  
  9.     digitalWrite(LED, HIGH);  
  10. }  

As you know, the two methods setup() and loop() are required, whether you code them or not. First, we declared a LED as 12, since we are targeting the LED + pin to digital pin 12. So, it's a good habit to declare a PIN in any integer type. Next, we set up the pinMode() method that decides the digital-pin behavior, whether it is input or output. Here, we are instructing the LED to glow, so it's an OUPUT command. That's why we ed OUTPUT and LED (that's a Pin number) as arguments. Fnally, we have a Loop() method that continually loops until you turn off your Arduino. Here, we called the method digitalWrite() that instructs the digital device to be in ON (HIGH) or OFF (LOW). We can glow our LED, so we ed digitalWrite(LED, HIGH). And this command instructs Arduino to glow the LED that is connected to PIN 12. And, on a continuous loop it will remain glowing until you turn off your Arduino.

And the following is how it will look:

Note: The Blue wire is my positive wire that is pointed to Digital Pin 12 and the Yellow wire is the negative wire that is pointed to the GND of the Arduino.


It's a beginning. I will continue this series where we will discuss some cool Arduino modules and shields. Better, you should order your own Arduino UNO from Flipkart, Amazon or eBay. And ensure you are buying a genuine one.

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