GPT答：

7i24.cn

要获取网络时间，您需要使用Arduino UNO开发板连接到互联网，并使用NTP协议从NTP服务器获取时间。以下是一个基本的代码示例：

```
#include <Ethernet.h>
#include <EthernetUdp.h>

// Enter a MAC address for your controller below.
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress timeServer(129,6,15,28); // time.nist.gov NTP server
const int timeZone = -5;     // Eastern Standard Time (USA)
EthernetUDP Udp;

void setup() {
    Ethernet.begin(mac);
    Udp.begin(123);
}

void loop() {
    sendNTPpacket(timeServer); // send an NTP packet to the time server
    delay(1000);

    if (Udp.parsePacket()) {
        byte packetBuffer[48];
        Udp.read(packetBuffer,sizeof(packetBuffer));

        unsigned long secsSince1900;
        secsSince1900 = (unsigned long)packetBuffer[40] << 24;
        secsSince1900 |= (unsigned long)packetBuffer[41] << 16;
        secsSince1900 |= (unsigned long)packetBuffer[42] << 8;
        secsSince1900 |= (unsigned long)packetBuffer[43];

        unsigned long epochTime = secsSince1900 -220898880;

       Serial.print("Unix time: ");
       Serial.println(epochTime);

       unsigned int hours= ((epochTime %86400L)/36000)%24 + timeZone; 
       unsigned int minutes= ((epochTime %36000L)/600)%60; 
       unsigned int seconds= ((epochTime %600L)/10)%60; 

      Serial.print("Current local time: ");
      Serial.print(hours);
      Serial.print(":");
      if(minutes<10) {
        Serial.print("0");
      }
      Serial.print(minutes);
      Serial.print(":");
      if(seconds<10) {
        Serial.print("0");
       }
       Serial.println(seconds);

    delay(1000); // wait a second before requesting the time again
  }
}

void sendNTPpacket(IPAddress& address)
{
  byte packetBuffer[48];
  memset(packetBuffer, 0, sizeof(packetBuffer));
  
  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
// Eight bytes of zero for Root Delay & Root Dispersion
packetBuffer[12] = 'I';
packetBuffer[13] = 'C';
packetBuffer[14] = 'H';
packetBuffer[15] = 'E';

Udp.beginPacket(address,123); 
Udp.write(packetBuf,sizeof(packetBuf)); 
Udp.endPacket();
}
```

上述代码使用Ethernet和EthernetUDP库连接到互联网，并从time.nist.gov NTP服务器获取时间。您可以根据需要更改服务器地址和时区。在loop()函数中，代码发送一个NTP数据包并等待响应。如果收到响应，则解析数据包以获取Unix时间戳，并将其转换为本地时间。

请注意，此示例假定您已经将Arduino UNO板连接到以太网网络并正确配置了网络设置。如果您还没有这样做，请参阅Arduino Ethernet Shield或Arduino WiFi Shield的文档以获取更多信息。