LED Blinking Patterns

Solving Approach

You have 4 LEDs (LED1–LED4), and the task is to generate the patterns shown in the pictures:

Pattern 1 → All LEDs OFF

Pattern 2 → LED1 and LED4 ON

Pattern 3 → LED3 ON

Pattern 4 → LED1 and LED2 ON

Pattern 5 → LED2 and LED3 ON

Code

int leds[] = {2, 3, 4, 5};  // LED1 = pin2, LED2 = pin3, LED3 = pin4, LED4 = pin5
int delayTime = 500;        // 0.5 second delay between patterns
void setup() {
  for (int i = 0; i < 4; i++) {
      pinMode(leds[i], OUTPUT);
        }
        }
        void loop() {
          // Pattern 1: All OFF
            digitalWrite(leds[0], LOW);
              digitalWrite(leds[1], LOW);
                digitalWrite(leds[2], LOW);
                  digitalWrite(leds[3], LOW);
                    delay(delayTime);
                      // Pattern 2: LED1 and LED4 ON
                        digitalWrite(leds[0], HIGH);
                          digitalWrite(leds[1], LOW);
                            digitalWrite(leds[2], LOW);
                              digitalWrite(leds[3], HIGH);
                                delay(delayTime);
                                  // Pattern 3: LED3 ON
                                    digitalWrite(leds[0], LOW);
                                      digitalWrite(leds[1], LOW);
                                        digitalWrite(leds[2], HIGH);
                                          digitalWrite(leds[3], LOW);
                                            delay(delayTime);
                                              // Pattern 4: LED1 and LED2 ON
                                                digitalWrite(leds[0], HIGH);
                                                  digitalWrite(leds[1], HIGH);
                                                    digitalWrite(leds[2], LOW);
                                                      digitalWrite(leds[3], LOW);
                                                        delay(delayTime);
                                                          // Pattern 5: LED2 and LED3 ON
                                                            digitalWrite(

Output

When you run the Arduino program, the 4 LEDs will blink in sequence following the above patterns.

So the output is the LEDs turning ON/OFF in order from Pattern 1 → 5, then repeating.

Video