#include <LiquidCrystal.h>
LiquidCrystal lcd(4,5,6,7,8,9);
int FlexSensor=A0;
int piezo=10;
int flexvalue=0;
int closed=180;
int tolerance=5;
unsigned long gateopened=0;
bool gateopen=false;

void setup()
{
  lcd.begin(16,2);
  pinMode(piezo,OUTPUT);
  lcd.print("GATE CLOSED");

}

void loop (){
  flexvalue=analogRead(FlexSensor);
  flexvalue=map(flexvalue,0,1023,0,180);
  
  if (flexvalue<(closed-tolerance)){
    if (!gateopen){
      lcd.clear();
      lcd.print("Gate Opening");
      gateopen=true;
      gateopened=millis();
    }
    unsigned long elapsedtime=millis()-gateopened;
    
    if (elapsedtime>7000){
      tone(piezo,1000);
    }
  
  }else if (flexvalue>=(closed-tolerance)&& gateopen){
    
    noTone(piezo);
    lcd.clear();
    lcd.print("Gate Closed");
    gateopen=false;
  }
  
}