Arduino - simple lights switch example

lights-switch-arduino.c

#define RED 4
#define GREEN 3
#define BLUE 2
#define COUNT (RED-BLUE+1)

#define BUTTON 7

int state[] = {LOW, LOW, LOW};

int toStateIndex(int pin) {
  return pin - BLUE;
}

void writeState(int pin) {
  digitalWrite(pin, state[toStateIndex(pin)]);
}

void applyState() {
  writeState(RED);
  writeState(BLUE);
  writeState(GREEN);
}

long long int lastSwitchTime;

void setup() {
  pinMode(RED, OUTPUT);
  pinMode(GREEN, OUTPUT);
  pinMode(BLUE, OUTPUT);

  lastSwitchTime = millis();

  applyState();

  Serial.begin(9600);
}

int currentLight = 0;

void updateState() {
  for (int i = 0; i < COUNT; i++) {
    state[i] = LOW;
  }
  state[currentLight] = HIGH;
}

int currentDelay = 0;
int delays[] = {2000, 1000, 500, 250, 500, 1000};
int delaysCount = sizeof(delays)/sizeof(int);

void loop() {
  if (millis() - lastSwitchTime >= delays[currentDelay]) {
    currentLight = (currentLight + 1) % COUNT;
    updateState();
    applyState();
    lastSwitchTime = millis();
  }

  // Button input handler.
  int value = analogRead(BUTTON);
  bool high = value > 1000;
  if (high) {
    delay(300);
    value = analogRead(BUTTON);
    high = value > 1000;
    if (!high) {
      currentDelay = (currentDelay + 1) % delaysCount;
      delay(1000);
    }
  }
}