Blinking multiple LEDs using switch case

Here, we will discuss a project to turn ON one led from multiple LEDs based on the value in the variable.

Let's start with the project.

Hardware Required

The components required for the project are listed below:

4 x red LED
4 x 220 Ohm Resistors
Arduino UNO R3 board
Jump wires

We can use any color LED as per our choice.

Principle

We will connect the four LEDs to pins 12, 11, 8, and 6 of the Arduino board. The resistors of 220 Ohm are connected in series with the LEDs.

The switch statement will compare the declared value of a variable with statements in other cases. The code associated with the matching case will run.

We will also change or rearrange the LEDs connected to the specified pin number on the board.

Structure of the project

The structure clearly shows the UNO board's pinout, and the four LEDs with resistors in series are connected to the board.

It is shown below:

Blinking multiple LEDs using switch case

Connection

The connection of the above project is discussed below:

Connect the resistor of 220 Ohm in series with the four LEDs. Now connect it to the pin number 12, 11, 8, and 6 of the Arduino board.
Connect the negative terminal of the five LEDs to the GND (Ground).

Sketch

Consider the below code:

void setup() 
{
  // initialize serial communication:
  Serial.begin(9600);
  // initializing the LED pins:
  for (int LEDpin = 6; LEDpin <13 ; LEDpin++) {
    pinMode(LEDpin, OUTPUT);
    // here, we have used for loop for initialization
  }
}
void loop() 
{
   int a = 3; // we can specify any variable name
    switch (a) 
    {
      case 1:
        digitalWrite(6, HIGH);
        break;
      case 2:
        digitalWrite(8, HIGH);
        break;
      case 3:
        digitalWrite(11, HIGH);
        break;
      case 4:
        digitalWrite(12, HIGH);
        break;
      default:
        // turn all the LEDs off if all the above cases does not matches:
        for (int LEDpin = 6; LEDpin <13; LEDpin++) 
        {
          digitalWrite(LEDpin, LOW);
        }
    }
  }

In the above code, the specified value of variable matches with case 3. Hence, the LED connected to pin number 11 will light up.