Question

3. Write an Arduino program to do the following function: When a switch connected to digital pin 4 is pressed, three LEDs connected to digital pins 5, 7, and 9 will blink ON and OFF sequentially (i.e. one after the other) with half a second delay between when an LED turns ON and turns OFF.

Answer 1

/*
Button

Turns on and off a light emitting diode(LED) connected to digital pin 13,
when pressing a pushbutton attached to pin 2.

The circuit:
- LEDS attached to pin 5,7,9 to ground
- pushbutton attached to pin 4 from +5V
- 10K resistor attached to pin 4 from ground

created 06/12/2018
by marysukanya <marysukanyaatgooglemail.com>
modified 30 Aug 2011
by Tom Igoe

This example code is in the public domain.

http://www.arduino.cc/en/Tutorial/Button
*/

// constants won't change. They're used here to set pin numbers:
const int buttonPin = 4;     // the number of the pushbutton pin
const int ledPin1 = 5;      // the number of the LED pin
const int ledPin2= 7;      // the number of the LED pin
const int ledPin3= 9;      // the number of the LED pin
// variables will change:
int buttonState = 0;         // variable for reading the pushbutton status

void setup() {
// initialize the LED pin as an output:

pinMode(ledPin1, OUTPUT);
pinMode(ledPin2, OUTPUT);
pinMode(ledPin3, OUTPUT);
// initialize the pushbutton pin as an input:
pinMode(buttonPin, INPUT);
}

void loop() {
// read the state of the pushbutton value:
buttonState = digitalRead(buttonPin);

// check if the pushbutton is pressed. If it is, the buttonState is HIGH:
if (buttonState == HIGH)
{
   digitalWrite(ledPin1, HIGH);
delay(500);                  // waits for a second
    digitalWrite(ledPin1, LOW);
  
    digitalWrite(ledPin2, HIGH);
delay(500);                  // waits for a second
    digitalWrite(ledPin2, LOW);

     digitalWrite(ledPin3, HIGH);
delay(500);                  // waits for a second
    digitalWrite(ledPin3, LOW);
  
}
}

/*please do like the work and rate good*/