timer_lamp_arduino_nano

#include <Keypad.h>

const byte ROWS = 4;
const byte COLS = 3;

char hexaKeys[ROWS][COLS] = {
  {1, 2, 3},
  {4, 5, 6},
  {7, 8, 9},
  {'*', '0', '#'}
};

byte rowPins[ROWS] = {6, 7, 8, 9};
byte colPins[COLS] = {10, 11, 12};

Keypad keypad = Keypad(makeKeymap(hexaKeys), rowPins, colPins, ROWS, COLS);
#define BINTANG 42 // nilai BINTANG
#define PAGAR 35 // nilai pagar
long dtKey = 0;
int key;
String line1;
String line2;


#include <LiquidCrystal_I2C.h>
Z lcd(0x27, 16, 2);

#define rel_lampu 5
#define rel_lampu_kerja 4

int state = 0;

#define STOP 0
#define RUN 1
#define FINISH 2

long set_waktu = 0;
long menit = 0, detik = 0;
unsigned long cur_time, old_time;
int buf_detik = 60, count_detik = 0;
String str_menit, str_detik;

void setup() {
  delay(100);
  pinMode(rel_lampu, OUTPUT);
  pinMode(rel_lampu_kerja, OUTPUT);

  Serial.begin(115200);
  lcd.init();

  lcd.backlight();
}

void loop() {
  key = keypad.getKey();
  if (key) {
    baca_key(); lcd.clear(); delay(20);
  }
  control();
  update_lcd();
}

void baca_key() {
  switch (state) {
    case STOP:
      if ( key == 48 )key = 0;
      if ( key < 10) {
        dtKey = dtKey * 10 + key;
        set_waktu = dtKey;
        menit = dtKey;
      }
      if (key == BINTANG) {
        dtKey = 0;
        set_waktu = 0;
      }
      if (key == PAGAR) {
        state = RUN;
        set_waktu = set_waktu * 60;
        menit = menit - 1;
      }
      break;
    case RUN:
      if (key == BINTANG) {
        set_waktu = 0;
        menit = 0;
        buf_detik = 60;
        count_detik = 0;
        state = STOP;
      }
      break;
    case FINISH:
      if (key == BINTANG) {
        set_waktu = 0;
        menit = 0;
        buf_detik = 60;
        count_detik = 0;
        state = STOP;
      }
      break;
  }
}


void get_text() {
  switch (state) {
    case STOP:
      line1 = "set waktu";
      line2 = "set :" + String(set_waktu) + " menit";
      break;
    case RUN:
      line1 = "RUNNING...";
      str_menit = menit < 10 ? "0" + String(menit) : String(menit);
      str_detik = buf_detik < 10 ? "0" + String(buf_detik) : String(buf_detik);
      line2 = "waktu: " + str_menit + ":" + str_detik;
      break;
    case FINISH:
      line1 = "FINISH...";
      line2 = "PRESS * BACK";
      break;
  }
}

void control() {
  switch (state) {
    case STOP:
      lampu_off();
      lampu_kerja_on();
      break;
    case RUN:
      lampu_on();
      lampu_kerja_on();

      cur_time = millis();
      if (cur_time - old_time >= 1000) {
        lcd.clear();
        if (count_detik == 60) {
          count_detik = 0;
          menit--;
        }
        if (buf_detik == 0) {
          buf_detik = 60;
        }

        count_detik ++;
        buf_detik--;
        set_waktu--;
        if (set_waktu == 0) {
          set_waktu = 0;
          menit = 0;
          state = FINISH;
        }
        old_time = cur_time;
      }
      break;

    case FINISH:
      lampu_off();
      lampu_kerja_on();
      break;
  }
}

void update_lcd() {
  get_text();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}

void lampu_on() {
  digitalWrite(rel_lampu, HIGH);
}

void lampu_off() {
  digitalWrite(rel_lampu, LOW);
}

void lampu_kerja_on(){
  digitalWrite(rel_lampu_kerja, HIGH);
}

void lampu_kerja_off(){
  digitalWrite(rel_lampu_kerja, LOW);
}