millis.ino

// Globals
unsigned long previousMillis = 0;
const long eventInterval = 5000;
// ...
 
  // Blocking "like delay()"
  unsigned long start = millis();
  while (millis() - start <= eventInterval) {
    // ...
  }
 
  // Non-blocking
  unsigned long currentMillis = millis();
  // ...
  if (currentMillis - previousMillis >= eventInterval) {
    previousMillis = currentMillis;
    // ...
  }