uv lamp

#include <LiquidCrystal.h>

const int rs = 8, en = 9, d4 =4, d5 = 5, d6 = 6, d7 = 7;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);


int verifyButton (int);

 int minutes=0;


void setup() {
  // set up the LCD's number of columns and rows:
  lcd.begin(16, 2);
  // Print a message to the LCD.
  lcd.print(minutes);
  lcd.setCursor(0, 1);
  lcd.print("minutes");
  pinMode (2, OUTPUT);
  digitalWrite (2, HIGH);
}

void loop() {
  int value = analogRead (A0);
  int result = verifyButton(value);
  lcd.setCursor (0,0);
  switch (result){
    case 2:{
        minutes++;
        delay (300);
        break;
        }
    case 3:{
        minutes--;
        delay (300);
        break;
    }
  }
  lcd.print(minutes);
  lcd.print("         ");
  if (value==0)
  {
    lcd.clear();
    delay (500);
    digitalWrite (2, LOW);
    while (1){
      for (int i=minutes*60; i>=0; i--){
            lcd.setCursor(0,0);
            lcd.print(i);
            lcd.print("  ");
            delay (1000);
      }
      lcd.setCursor(0,0);
      lcd.clear();
      digitalWrite(2, HIGH);
      lcd.print("Exposure finished");
      while (1){
        lcd.setCursor(0,1);
        lcd.print("");
      }
      }
 }
}

int verifyButton (int val){
  if (val<10) return 1;
  if (val<150) return 2;
  if (val<350) return 3;
  if (val<500) return 4;
  if (val<750)return 5;
  else return -2;
}