#include <Keypad.h>
#define RELAY 22
#define ROW_NUM     4 // four rows
#define COLUMN_NUM  4 // four columns

char keys[ROW_NUM][COLUMN_NUM] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

byte pin_rows[ROW_NUM]      = {19, 18, 5, 17}; // GPIO19, GPIO18, GPIO5, GPIO17 connect to the row pins
byte pin_column[COLUMN_NUM] = {16, 4, 0, 2};   // GPIO16, GPIO4, GPIO0, GPIO2 connect to the column pins

Keypad keypad = Keypad( makeKeymap(keys), pin_rows, pin_column, ROW_NUM, COLUMN_NUM );

const String set_jam = "30"; // change your time here
String input_jam;

void setup() {
  Serial.begin(9600);
  pinMode(RELAY,OUTPUT);
  input_jam.reserve(32); // maximum input characters is 33, change if needed
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    Serial.println(key);

    if (key == '*') {
      input_jam = ""; // clear input jam
    } else if (key == '#') {
      if (set_jam == input_jam) {
        Serial.println("MENGISI AIR HINGGA 30 MENIT");
        digitalWrite(RELAY,HIGH);
        delay(5000);
        digitalWrite(RELAY,LOW);

      } else {
        Serial.println("Waktu pengisian tidak tersedia!");
      }

      input_jam = ""; // clear input jam
    } else {
      input_jam += key; // append new character to input jam string
    }
  }
}