Menampilkan Tanggal dan Waktu pada LCD dengan NTP Server

 

//program NTP dengan LCD oleh indobot

#include <TimeLib.h>
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);
const char ssid[] = "*************";  //  hotspot anda
const char pass[] = "********";       // password hotspot anda

// NTP Servers:
static const char ntpServerName[] = "us.pool.ntp.org";
//static const char ntpServerName[] = "time.nist.gov";
//static const char ntpServerName[] = "time-a.timefreq.bldrdoc.gov";
//static const char ntpServerName[] = "time-b.timefreq.bldrdoc.gov";
//static const char ntpServerName[] = "time-c.timefreq.bldrdoc.gov";

//time zone untuk wilayah Indonesia adalah 7.
const int timeZone = 7;     // Central European Time
//const int timeZone = -5;  // Eastern Standard Time (USA)
//const int timeZone = -4;  // Eastern Daylight Time (USA)
//const int timeZone = -8;  // Pacific Standard Time (USA)
//const int timeZone = -7;  // Pacific Daylight Time (USA)


WiFiUDP Udp;
unsigned int localPort = 8888;  // port lokal untuk UDP packets

time_t getNtpTime();
void digitalClockDisplay();
void printDigits(int digits);
void sendNTPpacket(IPAddress &address);

void setup()
{
  Serial.begin(9600);
  lcd.begin();
  lcd.backlight();
  while (!Serial) ; 
  delay(250);
  Serial.println("TimeNTP Example");
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, pass);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.print("IP number assigned by DHCP is ");
  Serial.println(WiFi.localIP());
  Serial.println("Starting UDP");
  Udp.begin(localPort);
  Serial.print("Local port: ");
  Serial.println(Udp.localPort());
  Serial.println("waiting for sync");
  setSyncProvider(getNtpTime);
  setSyncInterval(300);
}

time_t prevDisplay = 0; // ketika jam digital mulai diaktifkan

void loop()
{
  if (timeStatus() != timeNotSet) {
    if (now() != prevDisplay) { //mengupdate display ketika jam berubah
      prevDisplay = now();
      digitalClockDisplay();
    }
  }
}

void digitalClockDisplay()
{
  // jam digital yang ditampilkan diserial monitor dan LCD
  Serial.print(hour());
  printDigits(minute());
  printDigits(second());
  Serial.print(" ");
  Serial.print(day());
  Serial.print(".");
  Serial.print(month());
  Serial.print(".");
  Serial.print(year());
  Serial.println();
  lcd.setCursor(0,0);
  lcd.print(hour());
  printDigits(minute());
  printDigits(second());
  lcd.setCursor(0,1);
  lcd.print(day());
  lcd.print(".");
  lcd.print(month());
  lcd.print(".");
  lcd.print(year());
}

void printDigits(int digits)
{
  // utility for digital clock display: prints preceding colon and leading 0
  //membuat jam digital menampilkan angka 0 ketika ada nilai 0-9
  lcd.print(":");
  if (digits < 10)
    lcd.print('0');
  lcd.print(digits);
}

/*-------- NTP code ----------*/

const int NTP_PACKET_SIZE = 48; // Waktu NTP ada dalam 48 byte pertama pesan
byte packetBuffer[NTP_PACKET_SIZE]; //buffer untuk menampung paket masuk & keluar

time_t getNtpTime()
{
  IPAddress ntpServerIP; // alamat server NTP

  while (Udp.parsePacket() > 0) ; // membuang semua data sebelumnya
  Serial.println("Transmit NTP Request");
  // get a random server from the pool
  WiFi.hostByName(ntpServerName, ntpServerIP);
  Serial.print(ntpServerName);
  Serial.print(": ");
  Serial.println(ntpServerIP);
  sendNTPpacket(ntpServerIP);
  uint32_t beginWait = millis();
  while (millis() - beginWait < 1500) {
    int size = Udp.parsePacket();
    if (size >= NTP_PACKET_SIZE) {
      Serial.println("Receive NTP Response");
      Udp.read(packetBuffer, NTP_PACKET_SIZE);  // membaca paket ke dalam buffer
      unsigned long secsSince1900;
      // konversi empat byte mulai dari lokasi 40 menjadi bilangan long integer
      secsSince1900 =  (unsigned long)packetBuffer[40] << 24;
      secsSince1900 |= (unsigned long)packetBuffer[41] << 16;
      secsSince1900 |= (unsigned long)packetBuffer[42] << 8;
      secsSince1900 |= (unsigned long)packetBuffer[43];
      return secsSince1900 - 2208988800UL + timeZone * SECS_PER_HOUR;
    }
  }
  Serial.println("No NTP Response :-(");
  return 0; // return 0 if unable to get the time
}

// send an NTP request to the time server at the given address
void sendNTPpacket(IPAddress &address)
{
  // set all bytes in the buffer to 0
  memset(packetBuffer, 0, NTP_PACKET_SIZE);
  // Initialize values needed to form NTP request
  // (see URL above for details on the packets)
  packetBuffer[0] = 0b11100011;   // LI, Version, Mode
  packetBuffer[1] = 0;     // Stratum, or type of clock
  packetBuffer[2] = 6;     // Polling Interval
  packetBuffer[3] = 0xEC;  // Peer Clock Precision
  // 8 bytes of zero for Root Delay & Root Dispersion
  packetBuffer[12] = 49;
  packetBuffer[13] = 0x4E;
  packetBuffer[14] = 49;
  packetBuffer[15] = 52;
  // all NTP fields have been given values, now
  // you can send a packet requesting a timestamp:
  Udp.beginPacket(address, 123); //NTP requests are to port 123
  Udp.write(packetBuffer, NTP_PACKET_SIZE);
  Udp.endPacket();
}