#include <LiquidCrystal.h>
#include <math.h>

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

#define LED 3
#define JOY A0
#define SENS 2

const int center = 512;
bool TURN_ON = false;

void ChangeDelay(int &dTime){
  static unsigned long timer;
  if((timer + 100) > millis()) return 0;

  if(analogRead(JOY) > center && dTime < 10){
    dTime++;
  }
  if(analogRead(JOY) < center && dTime > 2){
    dTime--;
  }

  timer = millis();
}

void setup()
{
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  pinMode(JOY, INPUT);
  pinMode(SENS, INPUT);
  lcd.begin(16, 2);
  lcd.print(" Current delay: ");
}

 
void loop()
{  
  static int delayTime = 2;
  static int oldDelay = 0;  
  static unsigned long timer = 0;

  ChangeDelay(delayTime);

  if(delayTime != oldDelay){
    lcd.setCursor(0, 1);
    lcd.print("                 ");
    lcd.setCursor(0, 1);
    lcd.print("   ");
    lcd.print(delayTime);
    lcd.print(" seconds");
  }

  if(digitalRead(SENS) == HIGH && TURN_ON == false){
    TURN_ON = true;
  }

  if(TURN_ON){
    digitalWrite(LED, HIGH);

    //Serial.print(TURN_ON);

    if(millis() - timer > delayTime * 1000){
      timer = millis();
      digitalWrite(LED, LOW);
      TURN_ON = false;
    }    
  }

  oldDelay = delayTime;
}