int buzzerPin = 6;   
int button = 2;     
int frequencies[] = {5000, 10000, 15000, 20000}; 
int currentFreqIndex = 0;  
int buttonState = 0;       
 
byte lastButtonState = LOW;
byte buzState = LOW;

void setup() {
  pinMode(buzzerPin, OUTPUT);
  pinMode(button, INPUT);
}

void loop() {
byte buttonState = digitalRead(button);
  if (buttonState != lastButtonState) {
    lastButtonState = buttonState;
    if (buttonState == HIGH) {
      buzState = (buzState == HIGH) ? LOW: HIGH;
      for (int freq = 100; freq <= 2000; freq += 100) {  
      tone(buzzerPin, freq);  
      delay(200);            
      }

      for (int freq = 2000; freq >= 100; freq -= 100) {  
      delay(200);
      }

      noTone(buzzerPin);  
      delay(500);   
    }
  }
}