NTP Clock – ESP8266

ESP8266 모델로 와이파이 연결되어 있으면 RTC 모듈 없이 시계 구현이 가능합니다. 본인의 와이파이 SSID와 패스워드 고쳐야 합니다.

#include 
#include 
#include 
#include 
 
// Module connection pins (Digital Pins)
#define CLK D3
#define DIO D4
 
#define GMT 9
 
char ssid[] = "your wifi ssid"; // change here
char pass[] = "your wifi password"; // change here
 
unsigned int localPort = 2390;
 
IPAddress timeServerIP;
const char* ntpServerName = "kr.pool.ntp.org";
 
const int NTP_PACKET_SIZE = 48; // NTP time stamp is in the first 48 bytes of the message
 
byte packetBuffer[ NTP_PACKET_SIZE]; //buffer to hold incoming and outgoing packets
 
// A UDP instance to let us send and receive packets over UDP
WiFiUDP udp;
 
TM1637Display display(CLK, DIO);
bool tick = false;
//byte hour1, minute1;
 
void setup()
{
  Serial.begin(115200);
 
  display.setBrightness(3);
 
  Serial.println();
  Serial.println();
 
  // We start by connecting to a WiFi network
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, pass);
 
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
 
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
 
  Serial.println("Starting UDP");
  udp.begin(localPort);
  Serial.print("Local port: ");
  Serial.println(udp.localPort());
 
  setSyncProvider(ntpTimeCheck);
  setSyncInterval(1800);
//  display.showNumberDec(hour() * 100 + minute(), true);
 
  if(timeStatus()!= timeSet) 
     Serial.println("Unable to sync");
  else
     Serial.println("Time sets fine");
}
 
void loop()
{
  if (tick == true) {
    display.showNumberDecEx(hour() * 100 + minute(), (0x80 >> 1), true);
  } else {
    display.showNumberDecEx(hour() * 100 + minute(), 0, true);
  }
  tick = !tick;
  delay(500);
}
 
time_t ntpTimeCheck()
{
  // get a random server from the pool
  WiFi.hostByName(ntpServerName, timeServerIP);
 
  sendNTPpacket(timeServerIP);
  delay(1000);
 
  int cb = udp.parsePacket();
  if (!cb) {
    Serial.println("packet failed");
    return now();
  }
  else {
    Serial.print("packet received, length=");
    Serial.println(cb);
 
    udp.read(packetBuffer, NTP_PACKET_SIZE);
 
    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);
    unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);
 
    unsigned long secsSince1900 = highWord << 16 | lowWord;
    Serial.print("Seconds since Jan 1 1900 = ");
    Serial.println(secsSince1900);
 
    Serial.print("Unix time = ");
 
    const unsigned long seventyYears = 2208988800UL;
 
    unsigned long epoch = secsSince1900 - seventyYears;
 
    Serial.println(epoch);
 
    epoch = epoch + GMT * 3600;
 
//    minute1 = minute(epoch);
//    hour1 = hour(epoch);
 
    return epoch;
  }
 
}
 
// send an NTP request to the time server at the given address
unsigned long sendNTPpacket(IPAddress& address)
{
  Serial.println("sending NTP packet...");
  // 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();
}