LED Blinking Patterns

Solving Approach

Code

#include <Arduino.h>
#include <stdint.h>

/* =======================
 * Pin Definitions
 * ======================= */
#define BUTTON_PIN  2

#define LED1_PIN    3
#define LED2_PIN    4
#define LED3_PIN    5
#define LED4_PIN    6

#define TIME_DELAY  400
#define PATTERN_COUNT 5

/* =======================
 * LED Series Definition
 * ======================= */
typedef union {
    uint8_t raw;
    struct {
        uint8_t led1    : 1;
        uint8_t led2    : 1;
        uint8_t led3    : 1;
        uint8_t led4    : 1;
        uint8_t unused  : 4;
    } bits;
} Led_Series_t;

/* =======================
 * Pattern State
 * ======================= */
typedef struct {
    uint8_t step;
} PatternState_t;

/* =======================
 * Pattern Function pointer Type
 * ======================= */
typedef void (*PatternFn)(Led_Series_t *leds, PatternState_t *state, bool tick);

/* =======================
 * Pattern Prototypes
 * ======================= */
void pattern1(Led_Series_t *, PatternState_t *, bool);
void pattern2(Led_Series_t *, PatternState_t *, bool);
void pattern3(Led_Series_t *, PatternState_t *, bool);
void pattern4(Led_Series_t *, PatternState_t *, bool);
void pattern5(Led_Series_t *, PatternState_t *, bool);

/* =======================
 * Pattern Table
 * ======================= */
PatternFn patterns[PATTERN_COUNT] = {
    pattern1,
    pattern2,
    pattern3,
    pattern4,
    pattern5
};

/* =======================
 * Utility: Non-blocking timer
 * ======================= */
bool time_elapsed(unsigned long* last, unsigned long interval)
{
    uint32_t now = millis();
    if (now - *last >= interval) {
        *last = now;
        return true;
    }
    return false;
}

/* =======================
 * Hardware Abstraction
 * ======================= */
void apply_leds(const Led_Series_t *leds)
{
    digitalWrite(LED1_PIN, leds->bits.led1);
    digitalWrite(LED2_PIN, leds->bits.led2);
    digitalWrite(LED3_PIN, leds->bits.led3);
    digitalWrite(LED4_PIN, leds->bits.led4);
}

/* =======================
 * Setup
 * ======================= */
void setup(void)
{
    Serial.begin(9600);

    pinMode(BUTTON_PIN, INPUT);   // external pull-down

    pinMode(LED1_PIN, OUTPUT);
    pinMode(LED2_PIN, OUTPUT);
    pinMode(LED3_PIN, OUTPUT);
    pinMode(LED4_PIN, OUTPUT);
}

/* =======================
 * Main Loop
 * ======================= */
void loop(void)
{
    static uint8_t pattern_index = 0;
    static uint8_t last_button = LOW;
    static unsigned long last_tick = 0;
    static PatternState_t state = {0};

    Led_Series_t leds = { .raw = 0 };

    bool tick = time_elapsed(&last_tick, TIME_DELAY);

    uint8_t button = digitalRead(BUTTON_PIN);

    /* Rising edge detection */
    if (button == HIGH && last_button == LOW) {
        pattern_index = (pattern_index + 1) % PATTERN_COUNT;
        state.step = 0;   // clean reset on pattern change
    }
    last_button = button;

    patterns[pattern_index](&leds, &state, tick);
    apply_leds(&leds);

    Serial.print("Pattern: ");
    Serial.println(pattern_index + 1);
}

/* =======================
 * Patterns Function Implementation
 * ======================= */

void pattern1(Led_Series_t *leds, PatternState_t *state, bool tick)
{
    if (tick) state->step ^= 1;
    leds->raw = state->step ? 0x0F : 0x00;
}

void pattern2(Led_Series_t *leds, PatternState_t *state, bool tick)
{
    if (tick) state->step ^= 1;
    leds->raw = state->step ? 0b0101 : 0b1010;
}

void pattern3(Led_Series_t *leds, PatternState_t *state, bool tick)
{
    if (tick) state->step = (state->step + 1) % 4;
    leds->raw = (1 << state->step);
}

void pattern4(Led_Series_t *leds, PatternState_t *state, bool tick)
{
    if (tick) state->step ^= 1;
    leds->raw = state->step ? 0b0011 : 0b1100;
}

void pattern5(Led_Series_t *leds, PatternState_t *state, bool tick)
{
    if (tick) state->step ^= 1;
    leds->raw = state->step ? 0b1001 : 0b0110;
}

Output

Video

https://wokwi.com/projects/450728352539128833