【零知ESP8266教程】快速入门19 使用NTP服务器获取网络时间

roc2 · 发表于 2019-11-2 14:37:34

上次的分享，我们获取了一枚天气信息，但是呢，信息最重要的属性之一就是时效性，如何去确认我们信息的时效性呢，简单，保持自己时间的准确喽。

Time is valuable thing！

时间对我们是很重要的。通常，我们需要进行时间校准（PS：在很多时候，你细心留意就发现时间是错误的），一般就可以用NTP服务器进行获取时间信息，下面使用零知-ESP8266上进行NTP时间的获取。

一、硬件
电脑，windows系统
零知ESP8266开发板
micro-usb线
二、
（1）打开零知开源开发软件，选择零知ESP8266开发板，界面如图所示：

（2）电脑连接零知ESP8266开发板

（3）烧写程序：
①可以直接选择软件中的示例程序

②也可以上传以下代码：

/*
* TimeNTP_ESP8266WiFi.ino
* Example showing time sync to NTP time source
*
* This sketch uses the ESP8266WiFi library
*/
#include <TimeLib.h>
#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
const char ssid[] = "xx"; // your network SSID (name)
const char pass[] = "xx"; // your network password
// NTP Servers:
static const char ntpServerName[] = "cn.ntp.org.cn";
//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";
const int timeZone = 8; //BeiJing in China
// const int timeZone = 1; // 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; // local port to listen for UDP packets
time_t getNtpTime();
void digitalClockDisplay();
void printDigits(int digits);
void sendNTPpacket(IPAddress &address);
void setup()
{
Serial.begin(9600);
while (!Serial) ; // Needed for Leonardo only
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; // when the digital clock was displayed
void loop()
{
if (timeStatus() != timeNotSet) {
if (now() != prevDisplay) { //update the display only if time has changed
prevDisplay = now();
digitalClockDisplay();
}
}
}
void digitalClockDisplay()
{
// digital clock display of the time
Serial.print(hour());
printDigits(minute());
printDigits(second());
Serial.print(" ");
Serial.print(day());
Serial.print(".");
Serial.print(month());
Serial.print(".");
Serial.print(year());
Serial.println();
}
void printDigits(int digits)
{
// utility for digital clock display: prints preceding colon and leading 0
Serial.print(":");
if (digits < 10)
Serial.print('0');
Serial.print(digits);
}
/*-------- NTP code ----------*/
const int NTP_PACKET_SIZE = 48; // NTP time is in the first 48 bytes of message
byte packetBuffer[NTP_PACKET_SIZE]; //buffer to hold incoming & outgoing packets
time_t getNtpTime()
{
IPAddress ntpServerIP; // NTP server's ip address
while (Udp.parsePacket() > 0) ; // discard any previously received packets
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); // read packet into the buffer
unsigned long secsSince1900;
// convert four bytes starting at location 40 to a 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();
}

复制代码

然后验证，并且上传到开发板。

四、结果

然后对照自己的时间：

赶紧动手检查看看自己的时间对不对呢？
我先校准自己的。

顺便问你们一句：有没有发现自己的时间变快了呢？（细思极恐）

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