Basics of Arduino Coding

You don’t require to know anything about coding before reading this article.

We are starting it from scratch…!

Arduino coding is very simple to understand and use in embedded system programming. We will discuss basic details about Arduino coding in this article so that you will be quite confident to start with Arduino coding and design your own circuits and ideas and projects using Arduino.

Here we assume that you have already installed Arduino IDE i.e. Arduino compiler software on your Windows PC. If you have not installed it yet, visit this direct downloading link of the software.

When downloading is complete, search the “arduino-1.8.19.zip” file in download folder of your PC, unzip the file by double clicking on it and then double click on “arduino-1.8.19.exe” file inside the zipped folder to start the installation of the software.

Now when you are ready, start reading the following topics. Remember it’s a series of posts to learn complete coding techniques about Arduino.

So when you complete reading the 1^st post, continue with the 2^nd post and 3^rd post and so on.

Take your own time to understand each topic completely and then go to the next post in this series.

The coding structure in Arduino programming is very simple. You must have at least two basic or default functions in every Arduino code, as shown below.

 void setup()
 {
  statement1;
  statement2;
  ..........
 }
 void loop()
 {
  statement1;
  statement2;
  ..........  
 }

 if(int i=5)
 {
  // write your commands below, 
  // which you want to execute when i=5
  command1;
  command2;
  ........
 }
 else
 {
  // write another commands below,
  // which you want to execute when i not equal to 5
  command3;
  command4;
  .........
 }

 switch(variable) 
 {
   // code to be executed if variable equals value1
   case value1:
   break;
   // code to be executed if variable equals value2
   case value2:
   break;
   // ......... add more cases as required
   
   default:
   // code to be executed if variable doesn't match any case
 }

 int LED=13;
 int irs=7;
 int IRStatus;
 void setup()
 {
   pinMode(irs,INPUT);
   pinMode(LED,OUTPUT);
 }
 void loop()
 {
   IRStatus = digitalRead(irs);
   switch(IRStatus) 
   {
     case 0: // in case 0, the LED is OFF
      digitalWrite(LED,LOW);
     break;
     case 1: // in case 1, the LED is ON
      digitalWrite(LED,HIGH);
     break;
   }
 }

 for(initialization; condition; increment)
 {
  statement1;
  statement2;
  ..........
 }

1. Initialization: This is where you initialize a loop control variable or set the initial conditions. It is typically a variable that will be used to control the loop.
2. Condition: This is a Boolean expression that is checked before each iteration. If the condition evaluates to true, the loop continues; otherwise, it exits.
3. Increment: This is an expression that is evaluated after each iteration of the loop. It is used to update the loop control variable.

 int LED=13;
 int i=0;
 void setup()
 {
   pinMode(LED,OUTPUT);
 }
 void loop()
 {
   // LED will blink 5 times for 1 sec each
   for(i=0;i<5;i++)
   {
     digitalWrite(LED,HIGH);
     delay(1000);
     digitalWrite(LED,LOW);
     delay(1000);
   }

   // LED will blink 4 times for 2 sec each
   for(i=0;i<4;i++)
   {
     digitalWrite(LED,HIGH);
     delay(2000);
     digitalWrite(LED,LOW);
     delay(2000);
   }
 }

The ‘while’ loop is used to execute particular commands when a condition is true. The general syntax of ‘while’ loop is as follows –

 while(condition)
 {
   statement1;
   statement2;
   ...........
 }

Suppose we have to produce alarm when obstacle is detected in front of IR sensor. To construct the circuit for this code, we connect buzzer at pin-11 and output of IR sensor at pin-7.

The example code is given below –

 int IRSensor=7;
 int buzzer=11;
 void setup()
 {
   pinMode(IRSensor,INPUT);
   pinMode(buzzer,OUTPUT);
 }
 void loop()
 {
   while(digitalRead(IRSensor==LOW))
   {
     digitalWrite(buzzer,HIGH);
     delay(1000);
     digitalWrite(buzzer,LOW);
   }
 }

  int IRSensor=7;
  int buzzer=11;
  void setup() 
  {
    pinMode(IRSensor,INPUT);
    pinMode(buzzer,OUTPUT); 
  }
  void loop() 
  {
    do 
    {
      digitalWrite(buzzer,HIGH);
      delay(1000);
      digitalWrite(buzzer,LOW);
    } 
    while(digitalRead(IRSensor)==LOW);
  }

 int i=1;
 void setup() 
 {
   Serial.begin(9600); 
 }
 void loop() 
 {
   int i=1;

   while (i<=10) 
   {
     if (i%2==0) 
     {
       // Skip even numbers using continue
       i++;
       continue;
     }

     // Print odd numbers
     Serial.println(i);

     // Increment the loop variable
     i++;
   }
   // write any other code outsite 'do-while' loop
 }

 // Function declaration
 int add(int a,int b);

 void setup() 
 {
    // Your setup code here
    Serial.begin(9600);
  
    // Function call
    int result=add(5,3);

    // Display the result using Serial Monitor
    Serial.println("Result: " + String(result));
 }

 void loop()
 {
    // Your loop code here
 }

  // User defined function
  int add(int a,int b) 
  {
    // Calculate the sum
    int sum=a+b;

    // Return the result
    return sum;
  }
}

The use of ‘goto’ is generally discouraged in modern programming due to its potential for creating spaghetti code and making the program difficult to understand and maintain. It’s often considered a bad practice because it can lead to unstructured and hard-to-follow code.
However, if you specifically want to convert the given code using ‘goto’, here’s an example:

 int IRSensor=7;
 int buzzer=11;

 void setup() 
 {
    pinMode(IRSensor, INPUT);
    pinMode(buzzer, OUTPUT);
 }

 void loop() 
 {
   startLoop:

   if(digitalRead(IRSensor)==LOW) 
   {
      digitalWrite(buzzer, HIGH);
      delay(1000);
      digitalWrite(buzzer, LOW);

      // Jump back to the beginning of the loop using goto
      goto startLoop;
   }
 }