#include <LiquidCrystal.h>

const int buttonPin = 2;      // the pin that the button is connected to
const int relayPin = 3;       // the pin that the relay is connected to
const int rs = 7, en = 8, d4 = 9, d5 = 10, d6 = 11, d7 = 12;  // the pins that the LCD is connected to

LiquidCrystal lcd(rs, en, d4, d5, d6, d7);  // initialize the LCD

int buttonState = HIGH;       // the current state of the button
int lastButtonState = HIGH;   // the previous state of the button
unsigned long lastDebounceTime = 0;    // the last time the button was pressed
unsigned long debounceDelay = 50;      // the debounce time; increase if the output flickers
bool relayState = false;      // the current state of the relay

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(relayPin, OUTPUT);
  digitalWrite(relayPin, LOW); // turn the relay off initially

  lcd.begin(16, 2);  // initialize the LCD with 16 columns and 2 rows
  lcd.print("Relay state:");   // display the initial message
  lcd.setCursor(0, 1);  // move the cursor to the second row
  lcd.print("OFF");
}

void loop() {
  // read the state of the button
  int reading = digitalRead(buttonPin);

  // debounce the button
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  if (millis() - lastDebounceTime > debounceDelay) {
    // update the button state only if debounceDelay has passed
    if (reading != buttonState) {
      buttonState = reading;

      // toggle the relay if the button is pressed
      if (buttonState == LOW) {
        relayState = !relayState;    // toggle the relay state
        digitalWrite(relayPin, relayState ? HIGH : LOW);  // set the relay pin accordingly
      }
    }
  }

  // update the LCD display with the current relay state
  lcd.setCursor(12, 1);   // move the cursor to the second row, 13th column
  lcd.print(relayState ? "ON " : "OFF");   // display the relay state as "ON" or "OFF"

  // save the button state for the next iteration
  lastButtonState = reading;
}