Example-code for timing based on millis() easier to understand through the use of example-numbers / avoiding delay()

[StefanL38]

easier to use non-blocking timing for constantly repeat something after a certain amount of time

const int ledPin =  LED_BUILTIN; // the number of the LED pin

int ledState = LOW;             // ledState used to set the LED

// easy to use helper-function for non-blocking timing
boolean TimePeriodIsOver (unsigned long &startOfPeriod, unsigned long TimePeriod) {
  unsigned long currentMillis  = millis();
  if ( currentMillis - startOfPeriod >= TimePeriod ) {
    // more time than TimePeriod has elapsed since last time if-condition was true
    startOfPeriod = currentMillis; // a new period starts right here so set new starttime
    return true;
  }
  else return false;            // actual TimePeriod is NOT yet over
}

unsigned long MyTestTimer =  0; // Timer-variables MUST be of type unsigned long

unsigned long myInterval = 1000;


void setup() {
  Serial.begin(115200);
  Serial.println("Setup-Start");
  pinMode(ledPin, OUTPUT);
}


// always put code that builds a senseful unit into its own function
void blinkLED() {
    if (ledState == LOW) {
      Serial.println("      ledState is LOW change it to HIGH");
      ledState = HIGH;
    } 
    else {
      Serial.println("ledState is HIGH change it to LOW");
      ledState = LOW;
    }
    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);  
}


void loop() {

  // once every x milliseconds (value stored in variable myInterval) 
  if ( TimePeriodIsOver(MyTestTimer, myInterval) ) {
    // execute code inside this if-condition
    blinkLED(); 
  }
}