Alarm clock, buzzer won't stop buzzing

Projects Programming
1

I am trying to make an alarm clock using a 16x2 LCD screen, a 10k potentiometer, a passive buzzer, and a DS3231 RTC. When I turn on the circuit, everything works fine, except the buzzer. I quickly threw together a fritzing. Any help would be appreciated!

#include <DS3231.h>
#include <LiquidCrystal.h>
#include <Wire.h>

LiquidCrystal lcd(12, 11, 5, 4, 3, 2);
DS3231 rtc(SDA,SCL);
Time t;

int Hor;
int Min;
int Sec;

const int buzzerPin = 8;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Wire.begin();
  rtc.begin();
  lcd.begin(16,2);

  pinMode(buzzerPin, OUTPUT);
  lcd.setCursor(0,0);
  lcd.print("Alarm on");
  delay(1000);
  lcd.clear();
}

void loop() {
  // put your main code here, to run repeatedly:
  serialDate();
  t=rtc.getTime();
  Hor = t.hour;
  Min = t.min;
  Sec = t.sec;

  lcd.setCursor(0,0);
  lcd.print("Time: ");
  lcd.print(rtc.getTimeStr());
  lcd.setCursor(0,1);
  lcd.print("Date: ");
  lcd.print(rtc.getDateStr());
   
  if( Hor == 11 &&  (Min == 32 || Min == 33)){ //Comparing the current time with the Alarm time
    buzz(3000);
    buzz(3000);

    lcd.clear();
    lcd.print("Alarm ON");
    lcd.setCursor(0,1);
    lcd.print("Alarming");

    buzz(3000);
    buzz(3000);
}
  delay(1000);
}
void buzz(int pitch){
  tone(buzzerPin,pitch);
  delay(40);
  noTone(buzzerPin);
  delay(40);
}
void printDate(){
  // Send Day-of-Week
  Serial.print(rtc.getDOWStr());
  Serial.print(" ");
  
  // Send date
  Serial.print(rtc.getDateStr());
  Serial.print(" -- ");

  // Send time
  Serial.println(rtc.getTimeStr());
  
  // Wait one second before repeating :)
  delay (1000);
}
void serialDate(){
  Serial.print("Date: ");
  Serial.print(rtc.getDateStr());
  Serial.println("Time: ");
  Serial.print(rtc.getTimeStr());
  delay(1000);
}

alarmclock fritz.PNG
alarmclock fritz.PNG1111×877 191 KB

2

You want to know when the time BECOMES the alarm time, not when the time IS the alarm time. The IDE has an example of how to do that.

3

What is the example name?

4

It is the state change example. This example probably looks at the change of a pin but it will be the same principle for the change of time. I usually use Sloeber with eclipse instead of the Arduino IDE but I will look up details in a couple of hours when I get back to my computer.

5

You want

File | Examples | 02.Digital | StateChangeDetection

(Arduino IDE 1.8.1) which is also available as https://www.arduino.cc/en/Tutorial/StateChangeDetection?from=Tutorial.ButtonStateChange

I suggest that you create a function that returns a boolean, with the function called something like isItAlarmTime which returns true or false appropriately. Instead of buttonState and lastButtonState, you will have alarmState and lastAlarmState. No debouncing (the delay(...) statement) will be necessary.