#include <LiquidCrystal_I2C.h>


const uint8_t redPin = 4 ;
const uint8_t ledPin = 7 ;

bool lastRedState = HIGH ;
uint16_t counter = 0 ;
uint32_t lastSecs = 0 ;

LiquidCrystal_I2C  lcd(0x27, 16, 2);



void setup() {
  Serial.begin(115200);
  pinMode(redPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT );
  lcd.init( );
  lcd.backlight();
}

void loop() {

  bool redState = digitalRead( redPin ) ;
  uint32_t secs = millis() / 1000 ;
  if ( redState == LOW ) {
    digitalWrite(ledPin, HIGH);
    if ( secs != lastSecs ) {
      lastSecs = secs ;
      if ( counter > 0 ) counter-- ;
    }

    if ( lastRedState == HIGH ) {
      lastRedState = redState ;
      counter = 105 ;   // should be 130
    }
    lcd.clear() ;
    if( counter < 100 ) lcd.print( counter );
    delay(500) ;
  }
  else {
    // clear up
    lcd.clear() ;
    digitalWrite(ledPin, LOW);
    lastRedState = HIGH ;
  }

}