#include <LiquidCrystal.h>

LiquidCrystal lcd(9, 10, 5, 4, 3, 2);
const int startButton = 11;
const int stopButton = 12;

unsigned long startTime = 0;
float elapsedTime = 0.0;
bool running = false;

void setup() {
  lcd.begin(16, 2);
  pinMode(startButton, INPUT_PULLUP);
  pinMode(stopButton, INPUT_PULLUP);
  lcd.print("Time: 0.00s");
}

void loop() {
  if (!running) {
    if (digitalRead(startButton) == LOW) {
      startTime = millis();
      running = true;
    }
  } else {
    unsigned long currentTime = millis();
    elapsedTime = (currentTime - startTime) / 1000.0;
    lcd.setCursor(0, 0);
    lcd.print("Time: ");
    lcd.print(elapsedTime, 2);
    lcd.print("s  ");
    
    if (digitalRead(stopButton) == LOW) {
      running = false;
    }
  }
}