// https://forum.arduino.cc/t/arduino-buzzer-millis-question/903934/1

// original code had a ///// important line, but that didna fix it
// constants won't change. Used here to set a pin number:
const int buzzerPin =  A2;// the number of the LED pin WAS LEDPin that is 13 for UNO

// Variables will change:
int buzzerState = LOW;             // ledState used to set the LED

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis_1 = 0;        // will store last time LED was updated
unsigned long previousMillis_2 = 0;        // will store last time LED was updated

// constants won't change:
const long interval_1 = 221;           // interval at which to blink (milliseconds)
const long interval_2 = 900;

void setup() {
  // set the digital pin as output:
  pinMode(buzzerPin, OUTPUT);
  digitalWrite(buzzerPin, LOW);
}

void loop() {
  // here is where you'd put code that needs to be running all the time.

  // check to see if it's time to blink the LED; that is, if the difference
  // between the current time and last time you blinked the LED is bigger than
  // the interval at which you want to blink the LED.
  unsigned long currentMillis = millis();

   if (currentMillis - previousMillis_1 >= interval_1) {
    // save the last time you blinked the LED
   previousMillis_1 = currentMillis;
   
   digitalWrite(buzzerPin, LOW);
  }


  if (currentMillis - previousMillis_2 >= interval_2) {
    // save the last time you blinked the LED
    previousMillis_2 = currentMillis;

//    comment out the following line to see the bad behaviour

    previousMillis_1 = currentMillis;  // reschedule the turn off time!
 
    digitalWrite(buzzerPin, HIGH);
  }
}