Arduino ESP8266 获取网络时间方法

#include <ESP8266WiFiMulti.h>

#include <WiFiUdp.h>

#include"rtctime.h"



#include <time.h>      // time() ctime()





ESP8266WiFiMulti WiFiMulti;



unsigned int localPort = 2390;  // local port to listen for UDP packets

IPAddress timeServerIP;  // time.nist.gov NTP server address

const char* ntpServerName = "time.nist.gov";

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;

struct rtc_tm rtcdate;



// NTP 服务器地址

const char* ntpServer = "pool.ntp.org";



// 时区和夏令时设置（例如：GMT+8）

const long gmtOffset_sec = 8 * 3600;

const int daylightOffset_sec = 0;





void setup() {

  // put your setup code here, to run once:

  Serial.begin(115200);

  delay(100);

  WiFi.mode(WIFI_STA);

  WiFiMulti.addAP("XGY-NJY", "njy123456");



  Serial.println('\n');

  while(WiFiMulti.run() != WL_CONNECTED) 

  {

    Serial.print("-.-");

    delay(250);

  }

  Serial.println('\n');

  

  Serial.print("Connected to :");

  Serial.println(WiFi.SSID());

  Serial.print("IP=");

  Serial.println(WiFi.localIP());



  Serial.println("Starting UDP");

  udp.begin(localPort);

  Serial.print("Local port: ");

  Serial.println(udp.localPort());



  // 配置时间

  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);

  // 等待并获取时间

  struct tm timeinfo;

  if (!getLocalTime(&timeinfo)) {

    Serial.println("Failed to obtain time");

    return;

  }

 char timeStringBuff[50]; // 缓冲区大小根据需要调整

   sprintf(timeStringBuff, "Current time: %04d-%02d-%02d %02d:%02d:%02d",

          timeinfo.tm_year + 1900,

          timeinfo.tm_mon + 1,

          timeinfo.tm_mday,

          timeinfo.tm_hour,

          timeinfo.tm_min,

          timeinfo.tm_sec);

  // 输出当前时间

  Serial.println(timeStringBuff);

  

}



void loop() {

  // put your main code here, to run repeatedly:

  // get a random server from the pool

  WiFi.hostByName(ntpServerName, timeServerIP);

  sendNTPpacket(timeServerIP);  // send an NTP packet to a time server

  // wait to see if a reply is available

  delay(1000);



  int cb = udp.parsePacket();

  if (!cb) 

  {

    Serial.println("no packet yet");

  } else 

  {

    Serial.print("packet received, length=");

    Serial.println(cb);

    // We've received a packet, read the data from it

    udp.read(packetBuffer, NTP_PACKET_SIZE);  // read the packet into the buffer

    // the timestamp starts at byte 40 of the received packet and is four bytes,

    //  or two words, long. First, esxtract the two words:



    unsigned long highWord = word(packetBuffer[40], packetBuffer[41]);

    unsigned long lowWord = word(packetBuffer[42], packetBuffer[43]);

    // combine the four bytes (two words) into a long integer

    // this is NTP time (seconds since Jan 1 1900):

    unsigned long secsSince1900 = highWord << 16 | lowWord;

    Serial.print("Seconds since Jan 1 1900 = ");

    Serial.println(secsSince1900);



    // now convert NTP time into everyday time:

    Serial.print("Unix time = ");

    // Unix time starts on Jan 1 1970. In seconds, that's 2208988800:

    const unsigned long seventyYears = 2208988800UL;

    // subtract seventy years:

    unsigned long epoch = secsSince1900 - seventyYears;

    // print Unix time:

    Serial.println(epoch);



    rtctime_gmtime(epoch,&rtcdate);

    Serial.println("The Beijing time is :"); 

  //下面变量要多定义一个，这样最后一个空闲作为结束标志

    char date_temp[11];

    char time_temp[9];

    sprintf(date_temp,"%04d-%02d-%02d",1900+rtcdate.tm_year,1+rtcdate.tm_mon,rtcdate.tm_mday);

    sprintf(time_temp,"%02d-%02d-%02d",8+rtcdate.tm_hour,rtcdate.tm_min,rtcdate.tm_sec);

    Serial.println(date_temp);

    Serial.println(time_temp);



/*

    // print the hour, minute and second:

    Serial.print("The UTC time is ");       // UTC is the time at Greenwich Meridian (GMT)

    Serial.print((epoch % 86400L) / 3600);  // print the hour (86400 equals secs per day)

    Serial.print(':');

    if (((epoch % 3600) / 60) < 10) 

    {

      // In the first 10 minutes of each hour, we'll want a leading '0'

      Serial.print('0');

    }

    Serial.print((epoch % 3600) / 60);  // print the minute (3600 equals secs per minute)

    Serial.print(':');

    if ((epoch % 60) < 10) 

    {

      // In the first 10 seconds of each minute, we'll want a leading '0'

      Serial.print('0');

    }

    Serial.println(epoch % 60);  // print the second

    */

  }

  // wait ten seconds before asking for the time again

  delay(10000);

}





// send an NTP request to the time server at the given address

void 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();

}