3. 搭配LCD1602_I2C製作網路時鐘

器材準備

LCD1602加上I2C模塊後,只需要佔用兩個IO,(SDA與SCL),剛好可用在ESP-01上,露天拍賣價格一組約100元上下,(若LCD1602跟I2C轉接板分開買再自己焊接會更便宜,大概70元左右)

LCD1602_I2C在arduino已有LiquidCrystal_I2C函式庫可用,不過在ESP-01上面並不適用,GOOGLE一下網路上已有大德改寫完成,網址如下:

https://github.com/agnunez/ESP8266-I2C-LCD1602

請先下載函式庫解壓到arduino底下的library資料夾,命名為LiquidCrystal_I2C

裡面附了範例程式,先打開arduino主程式,從檔案>>範例>>LiquidCrystal_I2C>>ESP8266I2CLCD

範例程式如下:其中較重要的說明是SDA接到ESP-01的GPIO0;SCL接到GPIO2

  // ESP8266 with 16x2 i2c LCD
  // Compatible with the Arduino IDE 1.6.6
  // Library https://github.com/agnunez/ESP8266-I2C-LCD1602
  // Original Library https://github.com/fdebrabander/Arduino-LiquidCrystal-I2C-library
  // Modified for ESP8266 with GPIO0-SDA GPIO2-SCL and LCD1206 display
  // edit library and change Wire.begin() by Wire.begin(sda,scl) or other GPIO's used for I2C
  // and access from lcd.begin(sda,scl)
  
#include <LiquidCrystal_I2C.h>
#include <Wire.h> 
  
  LiquidCrystal_I2C lcd(0x27,16,2); // Check I2C address of LCD, normally 0x27 or 0x3F
  
  uint8_t heart[8] = {0x0,0xa,0x1f,0x1f,0xe,0x4,0x0};  // example sprite bitmap
  
  void setup()  {
    lcd.begin(0,2);      // In ESP8266-01, SDA=0, SCL=2               
    lcd.backlight();
    lcd.createChar(1, heart);
  }
  
  void loop()  {
    lcd.home();                // At column=0, row=0
    lcd.print("ESP8266");   
    lcd.setCursor(0, 1);
    lcd.print("LiquidCrystalI2C");
    delay(500);
    lcd.setCursor(10, 0);      // At column=10, row=0
    lcd.write(byte(1));
    delay(500);
    lcd.setCursor(10, 0);      // At column=10, row=0
    lcd.print(" ");            // Wipe sprite
  }

再來,開啟另外一個範例程式,檔案>>範例>>ESP8266WIFI>>NTPClient,這是ESP8266取得網路時間的範例檔

程式內容如下:範例是使用電腦序列埠來顯示時間,不過我們這裡是把ESP-01當作主控板,並不會連接到電腦,所以底下那一堆serial.print()都要刪掉,改用lcd.print()

/*

 Udp NTP Client

 Get the time from a Network Time Protocol (NTP) time server
 Demonstrates use of UDP sendPacket and ReceivePacket
 For more on NTP time servers and the messages needed to communicate with them,
 see http://en.wikipedia.org/wiki/Network_Time_Protocol

 created 4 Sep 2010
 by Michael Margolis
 modified 9 Apr 2012
 by Tom Igoe
 updated for the ESP8266 12 Apr 2015 
 by Ivan Grokhotkov

 This code is in the public domain.

 */

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>

char ssid[] = "*************";  //  your network SSID (name)
char pass[] = "********";       // your network password


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

/* Don't hardwire the IP address or we won't get the benefits of the pool.
 *  Lookup the IP address for the host name instead */
//IPAddress timeServer(129, 6, 15, 28); // time.nist.gov NTP server
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;

void setup()
{
  Serial.begin(115200);
  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());
}

void loop()
{
  //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);


    // 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
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();
}

編輯Arduino程式

自己寫程式功力不行,改別人的程式會一點點,所以綜合上面兩個範例,摻在一起作撒尿牛丸了~~

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <LiquidCrystal_I2C.h>
#include <Wire.h> 
  
LiquidCrystal_I2C lcd(0x27,16,2); // Check I2C address of LCD, normally 0x27 or 0x3F
  
char ssid[] = "無線網路SSID";  //  your network SSID (name)
char pass[] = "無線網路密碼";       // your network password

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;

void setup()
{
    lcd.begin(0,2);      // In ESP8266-01, SDA=0, SCL=2               
    lcd.backlight();
  WiFi.begin(ssid, pass);
  udp.begin(localPort);
}

void loop()
{
  //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);
  
  udp.parsePacket();
     // 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;
    // now convert NTP time into everyday 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;

    lcd.clear();
    // print the hour, minute and second:
    lcd.print("UTC+8 time is ");       // UTC is the time at Greenwich Meridian (GMT)
    lcd.setCursor(0,1);
    lcd.print(((epoch  % 86400L ) / 3600) + 8 ); // print the hour (86400 equals secs per day)
    lcd.print(':');
    if ( ((epoch % 3600) / 60) < 10 ) {
      // In the first 10 minutes of each hour, we'll want a leading '0'
      lcd.print('0');
    }
    lcd.print((epoch  % 3600) / 60); // print the minute (3600 equals secs per minute)
    lcd.print(':');
    if ( (epoch % 60) < 10 ) {
      // In the first 10 seconds of each minute, we'll want a leading '0'
      lcd.print('0');
    }
    lcd.print(epoch % 60); // print the second

  // wait ten seconds before asking for the time again
  delay(9000);
}

// 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();
}

把上述程式內容修改無線網路部份後,上傳到ESP-01,(詳細上傳方式請參閱第1章),接著開始來接線了

電路接線圖

本範例的LCD1602模塊電壓是5V,市面上賣的也有3.3V的版本(比5V貴一點點),接上電源時請先確認您的是5V還是3.3V

接好線路,插上變壓器,若網路連線沒問題等待幾秒即會在螢幕上顯示目前時間了