#define BUZZER 5
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup()
{
  lcd.init();
  lcd.backlight();
  Serial.begin(9600);
  pinMode(BUZZER, OUTPUT);
}
void loop()
{
  lcd.setCursor(4, 0);
  lcd.print("BMP:");
  int jozo = buzzer();
  Serial.print("BMP:");
  Serial.println(jozo);
  lcd.println(jozo);
}

int buzzer(){
  int a = analogRead(A0);
  int bpm = map(a, 0, 1023, 60, 500);
  int interval = 60000 / bpm;

  tone(BUZZER, 800);
  delay(100);
  noTone(BUZZER);
  delay(interval - 100);
  return bpm;
}