const int ledPin[] = { 2, 3, 4, 5, 6, 7, 8, 9 };
const int numPins = sizeof(ledPin) / sizeof(ledPin[0]);
const int numStates = numPins / 2;
const unsigned long interval = 1000;
unsigned long previousTime;
int state;
void setup()
{
for ( int i = 0; i < numPins; ++i ) {
pinMode(ledPin[i], OUTPUT);
digitalWrite(ledPin[i], LOW );
}
digitalWrite(ledPin[0], HIGH );
digitalWrite(ledPin[1], HIGH );
}
void loop() {
unsigned long currentMillis = millis();
if (currentMillis - previousTime >= interval) {
previousTime = currentMillis;
digitalWrite(ledPin[state*2], LOW);
digitalWrite(ledPin[state*2+1], LOW);
state++;
if ( state >= numStates ) {
state = 0;
}
digitalWrite(ledPin[state*2], HIGH);
digitalWrite(ledPin[state*2+1], HIGH);
}
}