Adafruit Max6675 Library For Thermocouple Need To Be Modified To Run On ESP8266

Test the sketch "Wiring Thermocouple Max6675 on ESP8266 12E NodeMCU" of 14Core, and find Adafruit MAX6675 library installed using Library Manager is not compatible with ESP8266.

By replacing max6675.h and max6675.cpp with the ones from SirUli on github, copying other files on the link and commenting out the statements relating display functions, the sketch of 14Core has been compiled and run without fail on NodeMCU Dev Kit 1.0.

Also the serialthermocoupl.pde example sketch runs without fail.

I think the tutorials of 14Core had better specify from where the library they downloaded.

Wiring from 14Core

Output

Sketch

#include <max6675.h>
// #include <Wire.h>
// #include <Adafruit_GFX.h>
// #include <ESP_Adafruit_SSD1306.h>

// #define OLED_RESET 4

int ktcSO = 12;
int ktcCS = 13;
int ktcCLK = 14;

MAX6675 ktc(ktcCLK, ktcCS, ktcSO);
// Adafruit_SSD1306 display(OLED_RESET);
  
void setup() {
  Serial.begin(115200);
  Serial.println("Max6675 test");
  delay(500);
  // display.begin(SSD1306_SWITCHCAPVCC, 0x78>>1);
  // display.display();
  // delay(2000);
  // display.clearDisplay();
}

void loop() {
  // basic readout test
  //  
  //  display.setTextSize(2);
  //  display.setTextColor(WHITE);
  //  display.setCursor(52,10);
  //  display.print((char)223); 
  //  display.print("C = "); 
  //  display.print(ktc.readCelsius());
  //  display.print((char)223); 
  //  display.print("\t F = ");
  //  display.setCursor(52,30);
  //  display.println(ktc.readFahrenheit());

  float DC = ktc.readCelsius();
  // Read temperature as Celsius
  float DF = ktc.readFahrenheit();
  
   Serial.print("C = "); 
   Serial.print(ktc.readCelsius());
   Serial.print("\t F = ");
   Serial.println(ktc.readFahrenheit());
// 

 delay(1000);
 // displayData();
}

void displayData(){
  // display.setTextSize(1);
  // display.setCursor(5,1);
  // display.println("14CORE|THERMOCOUPLE");
  // display.setTextSize(2);
  // display.setTextColor(WHITE);
  // display.setCursor(18,20);
  // display.print((char)248); 
  // display.print("C:"); 
  // display.print(ktc.readCelsius());
  
    
  // display.setCursor(18,40);
  // display.print((char)248); 
  // display.print("F:");
  // display.println(ktc.readFahrenheit());
  // display.display();
  // display.clearDisplay();
}

Arduino Color LCD Shield Keypad Adjustable DS1307 Real Time Clock Using Time.h Library

The ColorLCDShield.h library comes with an example sketch ChronoLCD_Color which sets the time at compile stage and time cannot be adjusted. By reading time from DS1307, the sketch can get correct time after power interruption. By modifying the setTime(), time can be adjusted and restored to DS1307 real time clock. No re-compilation is needed any more.

Boards
1. Arduino Uno R3
2. cheaphousetek RTC Shield
3. Color LCD Shield

Photo

Sketch

/*
  ChronoLCD Color - An example sketch for the Color LCD Shield Library
  by: Jim Lindblom
  SparkFun Electronics
  date: 6/23/11
  license: CC-BY SA 3.0 - Creative commons share-alike 3.0
  use this code however you'd like, just keep this license and
  attribute. Let me know if you make hugely, awesome, great changes.
  
  This sketch draws an analog and digital clock on the Color LCD
  Shield. You can also use the on-board buttons to set the hours
  and minutes.
  
  Use the defines at the top of the code to set the initial time.
  You can also adjust the size and color of the clock.
  
  To set the time, first hit S3. Then use S1 and S2 to adjust the
  hours and minutes respsectively. Hit S3 to start the clock
  back up.
  
  This example code should give you a good idea of how to use
  the setCircle, setLine, and setStr functions of the Color LCD
  Shield Library.
*/
// Modified by Befun Hung on Jun. 22, 2014 
// 1) Sync time with DS1307 real time clock 
// 2) Use onboard keypad to adjust DS1307 time parameter
//    Press S1 get into adjustment mode, 
//    Press S2 to adjust or 
//    Press S3 to select which parameter to be adjusted with default to hour
//    Press S1 to save parameters to DS1307
// 3) Show date and weekday
// 4) Minor adjustment of analog clock

#include <Wire.h>
#include <Time.h>
#include <DS1307RTC.h> // a basic DS1307 library that returns time as a time_t
#include <ColorLCDShield.h>

char *dayOfWeek[] = {"", "SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
time_t t;
int displayAtSecond;

#define CLOCK_RADIUS 41  // radius of clock face
#define CLOCK_CENTER 50  // If you adjust the radius, you'll probably want to adjust this
#define H_LENGTH  23  // length of hour hand
#define M_LENGTH  33  // length of minute hand
#define S_LENGTH  37  // length of second hand

#define BACKGROUND  BLACK  // room for growth, adjust the background color according to daylight
#define C_COLOR  RED  // This is the color of the clock face, and digital clock
#define H_COLOR  BLUE  // hour hand color
#define M_COLOR  GREEN  // minute hand color
#define S_COLOR  YELLOW  // second hand color

LCDShield lcd;

int years, months, days;
int hours, minutes, seconds;
int buttonPins[3] = {3, 4, 5};

void setup()
{
  /* Set up the button pins as inputs, set pull-up resistor */
  for (int i=0; i<3; i++)
  {
    pinMode(buttonPins[i], INPUT);
    digitalWrite(buttonPins[i], HIGH);
  }
  
  /* Initialize the LCD, set the contrast, clear the screen */
  lcd.init(PHILIPS);
  lcd.contrast(-63);
  lcd.clear(BACKGROUND);
  
  setSyncProvider(RTC.get); // the function to get the time from the RTC
}

void loop()
{ 
  t = now();
  years = year(t);
  months = month(t);
  days = day(t);
  hours = hour(t);
  minutes = minute(t);
  seconds = second(t);
  
  if (!digitalRead(buttonPins[2]))
      setTime();  // If S3 was pressed, go set the time
      
  if (displayAtSecond != second(t)) {
    drawClock(); // Draw the clock face, this includes 12, 3, 6, 9
    displayAnalogTime(hours, minutes, seconds); // Draw the clock hands
    displayDateDayOfWeek(years, months, days);
    displayDigitalTime(hours, minutes, seconds); // Draw the digital clock text
    displayAtSecond = second(t);
  }
}
/* 
  setTime uses on-shield switches S1, S2, and S3 to set the time
  pressing S3 will exit the function. S1 increases hours, S2 
  increases seconds.
 */ 
void setTime()
{
  int setVariable = 3, checkStatus = 0;
  /* Reset the clock */
  years = year(t);
  months = month(t);
  days = day(t);
  hours = hour(t);
  minutes = minute(t);
  seconds = second(t);
  
  /* Draw the clock, so we can see the new time */
  drawClock();
  displayAnalogTime(hours, minutes, seconds);
  displayDateDayOfWeek(years, months, days);
  displayDigitalTime(hours, minutes, seconds);
    
  while (!digitalRead(buttonPins[2]))
    ; // wait till they let go of S1
  
  /* We'll run around this loop until S3 is pressed again */
  while(digitalRead(buttonPins[2]))
  {
    /* If S1 is pressed, we'll update the hours */
    if (!digitalRead(buttonPins[0]))
    {
      delay(100);
      setVariable = (setVariable + 1) % 6;  // Select year, month, day, hour, minute, second to change, default is year
        
      /* and update the clock, so we can see it */
      drawClock();
      displayAnalogTime(hours, minutes, seconds);
      displayDateDayOfWeek(years, months, days);
      displayDigitalTime(hours, minutes, seconds);
    }
    if (!digitalRead(buttonPins[1]))
    {
      delay(100);
      switch (setVariable) {
        case 0:{
          years = ((years + 1) % 100) + 2000;
          break;
        }
        case 1:{
          months = (months % 12) + 1; 
          break;
        }
        case 2:{
          days = (days % 31) + 1;
          break;
        }
        case 3:{
          hours = (hours + 1) % 24;
          break;
        }
        case 4:{
          minutes = (minutes + 1) % 60;
          break;
        }
        case 5:{
          seconds = (seconds + 1) % 60;
          break;
        }
      }
      // minutes++;  // Increase minutes by 1
      // if (minutes >= 60)
      //   minutes = 0;  // If minutes is 60, set it back to 0
        
      /* and update the clock, so we can see it */
      drawClock();
      displayAnalogTime(hours, minutes, seconds);
      displayDateDayOfWeek(years, months, days);
      displayDigitalTime(hours, minutes, seconds);
    }
  }
  /* Once S3 is pressed, we'll exit, but not until it's released */
  while(!digitalRead(buttonPins[2]))
    ;
  if ((months == 1 || months == 3 || months == 5 || months == 7 || months == 8 || months == 10 || months == 12) && days <= 31) checkStatus = 1;
  if ((months == 4 || months == 6 || months == 9 || months == 11) && days <=30) checkStatus = 1;
  if ((months == 2 && (years % 4) == 0) && days <= 29) checkStatus = 1;
  if ((months == 2 && (years % 4) != 0) && days <= 28) checkStatus = 1;
  if (checkStatus) {
    setTime(hours, minutes, seconds, days, months, years);
    RTC.set(now());
  }
}

/*
  displayDateDayOfWeek() takes in values for years, months, days.
  It'll print the date, day of week, in digital format, on the
  bottom of the screen.
*/
void displayDateDayOfWeek(int y, int m, int d)
{
  char dateChar[12];
  
  sprintf(dateChar, "%.4d-%.2d-%.2d ", y, m, d);
  
  /* Print the time on the clock */
  lcd.setStr(dateChar, 90, 10, 
              C_COLOR, BACKGROUND);
  lcd.setStr(dayOfWeek[weekday()], 90, 98, 
              C_COLOR, BACKGROUND);
}

/*
  displayDigitalTime() takes in values for hours, minutes and 
  seconds. It'll print the time, in digital format, on the
  bottom of the screen.
*/
void displayDigitalTime(int h, int m, int s)
{
  char timeChar[10]; // adjust the number of characters to avoid odd display
  
  sprintf(timeChar, "%.2d:%.2d:%.2d", h, m, s);
  
  /* Print the time on the clock */
  lcd.setStr(timeChar, 105, 26, C_COLOR, BACKGROUND);
}

/*
  drawClock() simply draws the outer circle of the clock, and '12',
  '3', '6', and '9'. Room for growth here, if you want to customize
  your clock. Maybe add dashe marks, or even all 12 digits.
*/
void drawClock()
{
  /* Draw the circle */
  lcd.setCircle(CLOCK_CENTER, 66, CLOCK_RADIUS, C_COLOR);
  
  /* Print 12, 3, 6, 9, a lot of arbitrary values are used here
     for the coordinates. Just used trial and error to get them 
     into a nice position. */
  lcd.setStr("12", CLOCK_CENTER - CLOCK_RADIUS, 66-9, C_COLOR, BACKGROUND);
  lcd.setStr("3", CLOCK_CENTER - 9, 66 + CLOCK_RADIUS - 12, C_COLOR, BACKGROUND);
  lcd.setStr("6", CLOCK_CENTER + CLOCK_RADIUS - 18, 66-4, C_COLOR, BACKGROUND);
  lcd.setStr("9", CLOCK_CENTER - 9, 66 - CLOCK_RADIUS + 4, C_COLOR, BACKGROUND);
}

/*
  displayAnalogTime() draws the three clock hands in their proper
  position. Room for growth here, I'd like to make the clock hands
  arrow shaped, or at least thicker and more visible.
*/
void displayAnalogTime(int h, int m, int s)
{
  double midHours;  // this will be used to slightly adjust the hour hand
  static int hx, hy, mx, my, sx, sy;
  
  /* Adjust time to shift display 90 degrees ccw
     this will turn the clock the same direction as text */
  h -= 3;
  m -= 15;
  s -= 15;
  if (h <= 0)
    h += 12;
  if (m < 0)
    m += 60;
  if (s < 0)
    s += 60;
    
  /* Delete old lines: */
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+sx, 66+sy, BACKGROUND);  // delete second hand
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+mx, 66+my, BACKGROUND);  // delete minute hand
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+hx, 66+hy, BACKGROUND);  // delete hour hand
  
  /* Calculate and draw new lines: */
  s = map(s, 0, 60, 0, 360);  // map the 0-60, to "360 degrees"
  sx = S_LENGTH * sin(3.14 * ((double) s)/180);  // woo trig!
  sy = S_LENGTH * cos(3.14 * ((double) s)/180);  // woo trig!
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+sx, 66+sy, S_COLOR);  // print second hand
  
  m = map(m, 0, 60, 0, 360);  // map the 0-60, to "360 degrees"
  mx = M_LENGTH * sin(3.14 * ((double) m)/180);  // woo trig!
  my = M_LENGTH * cos(3.14 * ((double) m)/180);  // woo trig!
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+mx, 66+my, M_COLOR);  // print minute hand
  
  midHours = minutes/12;  // midHours is used to set the hours hand to middling levels between whole hours
  h *= 5;  // Get hours and midhours to the same scale
  h += midHours;  // add hours and midhours
  h = map(h, 0, 60, 0, 360);  // map the 0-60, to "360 degrees"
  hx = H_LENGTH * sin(3.14 * ((double) h)/180);  // woo trig!
  hy = H_LENGTH * cos(3.14 * ((double) h)/180);  // woo trig!
  lcd.setLine(CLOCK_CENTER, 66, CLOCK_CENTER+hx, 66+hy, H_COLOR);  // print hour hand
}

NTP Server Synchronized DS1307 RTC Analog Data Logger

This sketch combine analog sensor data logger on Aug. 15, 2013 and NTP server synchronized DS1307 RTC using TimeAlarm library on Aug. 17, 2013.

The shetch use fixed IP, so DHCP server is not needed in the local area network.

Because the RTC is synchronized with NTP server, so the data logger keeps the time within 5 seconds. The NTP sync may fail sometimes depending on the network conditions.

Sketch

/*
 * NTPSynchronizedAnalogDataLogger.ino
 *
 * This sketch calls alarm functions at 7:30 am and at 7:30 pm (19:30)
 * and sync DS1307, Arduino system time 
 *
 * At startup the system time read from DS1307, then both sync with NTP 
 */

#include <Wire.h>
#include <Time.h>
#include <DS1307RTC.h>
#include <TimeAlarms.h>
#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <SD.h>
#define analogSensorStart 3 // sensor connect to A3
#define analogSensorEnd 3 // sensor connect to A3

// Enter a MAC address for your controller bellow.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
byte ip[] = {192, 168, 1, 177};
unsigned int localPort = 8888; // local port to listen for UDP packets
IPAddress timeServer(140, 112, 2, 188); // ntp2.ntu.edu.tw NTP server
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
EthernetUDP Udp;
// timeZoneOffset = (Time Zone) * 3600L eg. (+8) * 3600L = 28800L for Taipei, Taiwan
const long timeZoneOffset = 28800L; 
// sync to NTP server every "ntpSyncTime" seconds, set to 1 hour or more to be reasonable
unsigned long ntpSyncTime = 21600;
// adjust the sync latency with computer NTP client in seconds 
unsigned int syncLatency = 2;

// sd card variables
File file; // test file
const uint8_t SD_CS = 4; // SD chip select
String file_name = ""; // file name should not prefix with "prefix_word"
char fn[] = "MMDDHHMM.CSV";
int i=0;
int displayAtSecond = 0;
time_t t;

//------------------------------------------------------------------------------
// call back for file timestamps 
void dateTime(uint16_t* date, uint16_t* time) {
  time_t timeStamp = now();

  // return date using FAT_DATE macro to format fields
  *date = FAT_DATE(year(timeStamp), month(timeStamp), day(timeStamp));

  // return time using FAT_TIME macro to format fields
  *time = FAT_TIME(hour(timeStamp), minute(timeStamp), second(timeStamp));
} 
//------------------------------------------------------------------------------

void setup()
{
  Serial.begin(9600);
  Wire.begin();
  setSyncProvider(RTC.get); // the function to get the time from the RTC
  if (timeStatus() != timeSet)
    Serial.println("Unable to sync with the RTC");
  else
    Serial.println("RTC has set the system time");
  // set date time callback function
  SdFile::dateTimeCallback(dateTime);  
  // display RTC time
  Serial.print(year());
  Serial.print('-');
  Serial.print(month());
  Serial.print('-');
  Serial.print(day());
  Serial.print(' ');
  Serial.print(hour());
  Serial.print(':');
  Serial.print(minute());
  Serial.print(':');
  Serial.print(second());
  Serial.println(" --- RTC Time");
  // create the alarms 
  Alarm.alarmRepeat(7,30,0, ntpSyncDS1307);  // 7:30am every day
  Alarm.alarmRepeat(19,30,0, ntpSyncDS1307);  // 7:30pm every day 
  
  // start Ethernet and UDP
  Ethernet.begin(mac, ip);
  Udp.begin(localPort); 
  // Serial.println("connect to ntp server");
  ntpSyncDS1307();
  
  // process file name string
  t = now();
  if (month(t) < 10) {
      file_name = String(file_name + '0' + String(month(t), DEC));
    }
    else {
    file_name = String(file_name +String(month(t), DEC));
    }
  if (day(t) < 10) {
      file_name = String(file_name + '0' + String(day(t), DEC));
    }
    else {
    file_name = String(file_name +String(day(t), DEC));
    }
  if (hour(t) < 10) {
      file_name = String(file_name + '0' + String(hour(t), DEC));
    }
    else {
    file_name = String(file_name +String(hour(t), DEC));
    }
  if (minute(t) < 10) {
      file_name = String(file_name + '0' + String(minute(t), DEC));
    }
    else {
    file_name = String(file_name +String(minute(t), DEC));
    }

  file_name = String(file_name + ".CSV");

  for (i=0;i<=file_name.length();i++) {
    fn[i] = file_name.charAt(i);
  }
  Serial.print("File Name: ");
  Serial.println(fn);
  pinMode(10, OUTPUT);
  digitalWrite(10, HIGH);
  if (!SD.begin(SD_CS)) {
    Serial.println("SD failed");
    // while(1);
  }
}

void loop(){
  t = now();
  if (displayAtSecond != second(t)) {
    analogSensorDataLogger();
    displayAtSecond = second(t);
  }
  Alarm.delay(100); // wait 1/10 second between cycles
}

// functions to be called when an alarm triggers:
void ntpSyncDS1307() {
  sendNTPpacket(timeServer); // send an NTP packet to a time server
  // wait to see if a replay is available
  delay(1000);
  if (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 timstamp starts at byte 40 of the received packet and is four bytes,
    // or two words, long. First, extract 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 = 2208988800L;
    // substract seventy years:
    unsigned long epoch = secsSince1900 - seventyYears + timeZoneOffset + syncLatency;
    setTime(epoch);
    RTC.set(epoch);
    // output time and "Sync OK" message every sync 
    Serial.print(year());
    Serial.print('-');
    Serial.print(month());
    Serial.print('-');
    Serial.print(day());
    Serial.print(' ');
    Serial.print(hour());
    Serial.print(':');
    Serial.print(minute());
    Serial.print(':');
    Serial.print(second());
    Serial.print(' ');
    Serial.println("Sync OK");
  }
}

// send an NTP request to the time server at the given address
unsigned long 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 clodk
  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);
  Udp.write(packetBuffer, NTP_PACKET_SIZE);
  Udp.endPacket();
}

void analogSensorDataLogger() { 
  String data_string = "";
  data_string = String(year(t), DEC);
  data_string += "/";
  if (month(t) < 10) {
      data_string = String(data_string + '0' + String(month(t), DEC));
    }
    else {
    data_string = String(data_string +String(month(t), DEC));
    }
  data_string += "/";
  if (day(t) < 10) {
      data_string = String(data_string + '0' + String(day(t), DEC));
    }
    else {
    data_string = String(data_string +String(day(t), DEC));
    }
  data_string += " ";
  if (hour(t) < 10) {
      data_string = String(data_string + '0' + String(hour(t), DEC));
    }
    else {
    data_string = String(data_string +String(hour(t), DEC));
    }
  data_string += ":";
  if (minute(t) < 10) {
      data_string = String(data_string + '0' + String(minute(t), DEC));
    }
    else {
    data_string = String(data_string +String(minute(t), DEC));
    }
  data_string += ":";  
  if (second(t) < 10) {
      data_string = String(data_string + '0' + String(second(t), DEC));
    }
    else {
    data_string = String(data_string +String(second(t), DEC));
    }
  data_string += ",";

  //read sensor value from A0-A3 and append to the string
  for (int analogPin = analogSensorStart; analogPin <= analogSensorEnd; analogPin++)
    {
    int sensor = analogRead(analogPin);
    data_string += String(sensor);
    if (analogPin < analogSensorEnd) {
      data_string += ",";
      }
    }
  
  file = SD.open(fn, FILE_WRITE);
  if (file) {
    file.println(data_string);
    file.close();
    Serial.println(data_string);
    }
    else {
      Serial.print("error opening ");
      Serial.println(fn);
    }
}

NTP Server Synchronized LCD Keypad Adjustable Clock With Temperature Using Time.h Library

This sketch extend from post on Aug. 01, 2013 by adding synchronizing with NTP server.The Uno will synchronize with NTP server every 6 hours and override the time adjusted by using LCD shield keypad. An alternative to synchronize at certain time is to use Alarm.alarmRepeat() function in <TimAlarms.h>. The latency is about 2 seconds in my case, adjust the latency according your Internet connection condition. The binary sketch size is 19,614 bytes.

Requirements:

1. Arduino Uno R3
2. RTC (DS1307) Sensor Shield
3. W5100 Ethernet Shield
4. LCD Keypad Shield
5. LM35 Temperature Sensor Breakout

Usage

1. Use <RIGHT> keypad to enter set mode.
2. Use <RIGHT> to navigate on parameter to be modified.
3. Use <UP> to set value of the aimed parameter.
4. Use <DOWN> to set value of the aimed parameter.
5. Use <SELECT> to save date and time to RTC.
6. Use <LEFT> to leave set mode.

Schetch

/*
 * TimeRTC.pde
 * example code illustrating Time library with Real Time Clock.
 * the sketch works on Arduino IDE 1.05
 * 1) modified by Befun Hung on Jul. 28, 2013 
 *    changing the sequence to year, month, day, hour, minute, second
 *    adding the day of week
 *    almost same function as sketch on May 1, 2012
 * 2) modified by Befun Hung on Jul. 29, 2013
 *    change display device to LCD Shield
 *    adding temperature readout from LM35
 *    the sketch does not contain delay() in the loop section 
 * 3) modified by Befun Hung on Jul. 31, 2013
 *    divide digitalClockDisplay() into dateDisplay(), weekdayDisplay(), timeDisplay() and temperatureDisplay()
 *    use time_t t to store the value of now()
 * 4) modified by Befun Hung on Aug. 04, 2013
 *    adding ntpSyncDS1307() to synchronize DS1307 real time clock with NTP server
 */

#include <SPI.h>
#include <Ethernet.h>
#include <EthernetUdp.h>
#include <Time.h>
#include <Wire.h>  
#include <DS1307RTC.h>  // a basic DS1307 library that returns time as a time_t
#include <LiquidCrystal.h>
LiquidCrystal lcd(8,9,4,5,6,7);

#define btnRIGHT 0
#define btnUP 1
#define btnDOWN 2
#define btnLEFT 3
#define btnSELECT 4
#define btnNONE 5

char *dayOfWeek[] = {"", "SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
int lcdKey = 0;
int adcKeyIn = 0;
time_t t;
int potPin = 3; // change potPin value to 0, 1, 2 for A0, A1, A2 respectly
float temperature = 0;
int displayAtSecond;

// Enter a MAC address for your controller bellow.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = {0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED};
unsigned int localPort = 8888; // local port to listen for UDP packets
IPAddress timeServer(140, 112, 2, 188); // ntp2.ntu.edu.tw NTP server
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
EthernetUDP Udp;
// timeZoneOffset = (Time Zone) * 3600L eg. (+8) * 3600L = 28800L for Taipei, Taiwan
const long timeZoneOffset = 28800L; 
// sync to NTP server every "ntpSyncTime" seconds, set to 1 hour or more to be reasonable
unsigned long ntpSyncTime = 21600;
// keep track of how long ago we updated the NTP server
unsigned long ntpLastUpdate = 0;
// adjust the sync latency with computer NTP client in seconds 
unsigned int syncLatency = 2;

void setup()  {
  lcd.begin(16,2);
  lcd.print("*cheaphousetek*");
  lcd.setCursor(0,1);
  setSyncProvider(RTC.get);   // the function to get the time from the RTC
  if(timeStatus()!= timeSet) 
     lcd.print("Unable to sync");
  else
     lcd.print("Sync system time ");
  displayAtSecond = second();
  delay(2000);
  lcd.clear();
  // start Ethernet and UDP
  if (Ethernet.begin(mac) == 0) {
    lcd.setCursor(0,1);
    lcd.print("DHCP failed");
    for (;;);
  }
  Udp.begin(localPort);
}

void loop()
{
  if ((now() - ntpLastUpdate) >= ntpSyncTime) {
    ntpSyncDS1307();
  }
  // for reading keypad stroke to set the date and time once the RIGHT is pressed
  t = now();
  lcdKey = readLCDButton();
  if (lcdKey == btnRIGHT) {
    keypadSetDateTime();
  }
  // for LCD shield to disp date, day of the week, time and temperature once a second
  if (displayAtSecond != second(t)) { 
    digitalClockDisplay(); 
    displayAtSecond = second(t); 
  }
}

int readLCDButton() {
  adcKeyIn = analogRead(0);
  delay(200);
  // read the value from the sensor
  // my buttons when read are centered at these values: 0, 144, 329, 504, 741
  // we add approx 50 to those values and check to see if we are close
  if (adcKeyIn > 1000) return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result
  if (adcKeyIn < 73) return btnRIGHT;
  if (adcKeyIn < 237) return btnUP;
  if (adcKeyIn < 415) return btnDOWN;
  if (adcKeyIn < 623) return btnLEFT;
  if (adcKeyIn < 882) return btnSELECT;
  return btnNONE; // when all others fail, return this...
}

void digitalClockDisplay(){
  // digital clock display of the time
  dateDisplay();
  weekdayDisplay();
  timeDisplay();
  temperatureDisplay();  
}

void dateDisplay() {
  lcd.setCursor(0,0);
  lcd.print(year(t));
  lcd.print('-');
  if (month(t) < 10) {
    lcd.print('0');
  }
  lcd.print(month(t));
  lcd.print('-');
  if (day(t) < 10) {
    lcd.print('0');
  }
  lcd.print(day(t));
  // lcd.print(' ');
}

void weekdayDisplay() {
  lcd.setCursor(11,0);
  lcd.print(dayOfWeek[weekday()]);
}

void timeDisplay() {
  lcd.setCursor(0,1);
  if (hour(t) < 10) {
    lcd.print('0');
  }
  lcd.print(hour(t));
  lcd.print(':');
  if (minute(t) < 10) {
    lcd.print('0');
  }
  lcd.print(minute(t));
  lcd.print(':');
  if (second(t) < 10) {
    lcd.print('0');
  }
  lcd.print(second(t));
  // lcd.print(' ');
}

void temperatureDisplay() {
  int span = 10;
  long aRead = 0;
  unsigned long temp;
  
  for (int i=0;i<span;i++) {
    aRead = aRead + analogRead(potPin);
  }
  temperature = (aRead / span * 500.0 / 1024.0); // for other analog sensor change the constants
  printTenths(long (temperature * 10));
  lcd.setCursor(14,1);
  lcd.print(char(223));
  // lcd.setCursor(15,1);
  lcd.print('C'); 
}

void printTenths(long value) {
  // prints a value of 123 as 12.3
  lcd.setCursor(10,1);
  lcd.print(value / 10);
  lcd.setCursor(12,1);
  lcd.print('.');
  lcd.setCursor(13,1);
  lcd.print(value % 10);
}

void keypadSetDateTime() {
  int setYear=year(t), setMonth=month(t), setDay=day(t), setHour=hour(t), setMinute=minute(t), setSecond=second(t);
  int setVariable=0, checkStatus=0;
  
  dateDisplay();
  timeDisplay();
  while(true) {
    lcdKey = readLCDButton();
    switch(lcdKey) {
      case btnNONE:
      {
        lcd.blink();
        if (setVariable == 0) lcd.setCursor(3,0);
        if (setVariable == 1) lcd.setCursor(6,0);
        if (setVariable == 2) lcd.setCursor(9,0);
        if (setVariable == 3) lcd.setCursor(1,1);
        if (setVariable == 4) lcd.setCursor(4,1);
        if (setVariable == 5) lcd.setCursor(7,1);
        break;
      }
      case btnRIGHT:
      {
        setVariable = (setVariable + 1) % 6;
        break;
      }
      case btnLEFT:
      {
        lcd.noBlink();
        lcd.clear();
        return;
      }
      case btnUP:
      {
        if (setVariable == 0) {
          setYear = ((setYear + 1) % 100) + 2000;
          lcd.setCursor(0,0);
          lcd.print(setYear);
        }
        if (setVariable == 1) {
          setMonth = (setMonth % 12) + 1;
          lcd.setCursor(5,0);
          if (setMonth < 10) {
            lcd.print('0');
            lcd.print(setMonth);
          }
          else {
            lcd.print(setMonth);
          }
        }
        if (setVariable == 2) {
          setDay = (setDay % 31) + 1;
          lcd.setCursor(8,0);
          if (setDay < 10) {
            lcd.print('0');
            lcd.print(setDay);
          }
          else {
            lcd.print(setDay);
          }
        }
        if (setVariable == 3) {
          setHour = (setHour + 1) % 24;
          lcd.setCursor(0,1);
          if (setHour < 10) {
            lcd.print('0');
            lcd.print(setHour);
          }
          else {
            lcd.print(setHour);
          }
        }
        if (setVariable == 4) {
          setMinute = (setMinute + 1) % 60;
          lcd.setCursor(3,1);
          if (setMinute < 10) {
            lcd.print('0');
            lcd.print(setMinute);
          }
          else {
            lcd.print(setMinute);
          }
        }
        if (setVariable == 5) {
          setSecond = (setSecond + 1) % 60;
          lcd.setCursor(6,1);
          if (setSecond < 10) {
            lcd.print('0');
            lcd.print(setSecond);
          }
          else {
            lcd.print(setSecond);
          }
        }
        break;
      }
      case btnDOWN:
      {
        if (setVariable == 0) {
          setYear = ((setYear - 1) % 100) + 2000;
          lcd.setCursor(0,0);
          lcd.print(setYear);
        }
        if (setVariable == 1) {
          setMonth = ((setMonth - 1) % 12);
          if (setMonth == 0) {
            setMonth = setMonth + 12;
          }
          lcd.setCursor(5,0);
          if (setMonth < 10) {
            lcd.print('0');
            lcd.print(setMonth);
          }
          else {
            lcd.print(setMonth);
          }
        }
        if (setVariable == 2) {
          setDay = ((setDay - 1) % 31);
          if (setDay == 0) {
            setDay = setDay + 31;
          }
          lcd.setCursor(8,0);
          if (setDay < 10) {
            lcd.print('0');
            lcd.print(setDay);
          }
          else {
            lcd.print(setDay);
          }
        }
        if (setVariable == 3) {
          setHour = (setHour - 1 + 24) % 24;
          lcd.setCursor(0,1);
          if (setHour < 10) {
            lcd.print('0');
            lcd.print(setHour);
          }
          else {
            lcd.print(setHour);
          }
        }
        if (setVariable == 4) {
          setMinute = (setMinute - 1 + 60) % 60;
          lcd.setCursor(3,1);
          if (setMinute < 10) {
            lcd.print('0');
            lcd.print(setMinute);
          }
          else {
            lcd.print(setMinute);
          }
        }
        if (setVariable == 5) {
          setSecond = (setSecond - 1 + 60) % 60;
          lcd.setCursor(6,1);
          if (setSecond < 10) {
            lcd.print('0');
            lcd.print(setSecond);
          }
          else {
            lcd.print(setSecond);
          }
        }
        break;
      }
      case btnSELECT:
      {
        if ((setMonth == 1 || setMonth == 3 || setMonth == 5 || setMonth == 7 || setMonth == 8 || setMonth == 10 || setMonth == 12) && setDay <= 31) checkStatus = 1;
        if ((setMonth == 4 || setMonth == 6 || setMonth == 9 || setMonth == 11) && setDay <=30) checkStatus = 1;
        if ((setMonth == 2 && (setYear % 4) == 0) && setDay <= 29) checkStatus = 1;
        if ((setMonth == 2 && (setYear % 4) != 0) && setDay <= 28) checkStatus = 1;
        if (checkStatus) {
          setTime(setHour, setMinute, setSecond, setDay, setMonth, setYear);
          RTC.set(now());
        }
        break;
      }
    }
  }
}

void ntpSyncDS1307() {
  sendNTPpacket(timeServer); // send an NTP packet to a time server
  // wait to see if a replay is available
  delay(1000);
  if (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 timstamp starts at byte 40 of the received packet and is four bytes,
    // or two words, long. First, extract 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 = 2208988800L;
    // substract seventy years:
    unsigned long epoch = secsSince1900 - seventyYears + timeZoneOffset + syncLatency;
    setTime(epoch);
    RTC.set(epoch);
    ntpLastUpdate = now();
  }
}

// send an NTP request to the time server at the given address
unsigned long 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 clodk
  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);
  Udp.write(packetBuffer, NTP_PACKET_SIZE);
  Udp.endPacket();
}

Display Date and Time In Arduino Serial Monitor Using Time.h

First, Download Time.h from the following link.
http://playground.arduino.cc/uploads/Code/Time.zip

Read usage of Time.h library.
http://playground.arduino.cc/Code/time

The function is almost same as the sketch post on May 1, 2012, except adding displaying the day of week.

Pins Used

Analog pins 4.and 5 are used for I2C protocol implemented by Maxim DS1307.

Serial Monitor Output

Sketch

/*
 * TimeRTC.pde
 * example code illustrating Time library with Real Time Clock.
 * the sketch works on Arduino IDE 1.05
 * modified by Befun Horng on Jul. 28, 2013
 * changing the sequence to year, month, day, hour, minute, second
 * adding the day of week
 * almost same function as sketch on May 1, 2012
 */

#include <Time.h>
#include <Wire.h>
#include <DS1307RTC.h>  // a basic DS1307 library that returns time as a time_t
char *dayOfWeek[] = {"", "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
void setup()  {
  Serial.begin(9600);
  setSyncProvider(RTC.get);   // the function to get the time from the RTC
  if(timeStatus()!= timeSet)
     Serial.println("Unable to sync with the RTC");
  else
     Serial.println("RTC has set the system time");    
}

void loop()
{
   digitalClockDisplay();
   delay(1000);
}

void digitalClockDisplay(){
  // digital clock display of the time
  Serial.print(year());
  Serial.print("-");
  if (month() < 10) {
    Serial.print('0');
  }
  Serial.print(month());
  Serial.print("-");
  if (day() < 10) {
    Serial.print('0');
  }
  Serial.print(day());
  Serial.print(" ");
  Serial.print(dayOfWeek[weekday()]);
  Serial.print(' ');
  if (hour() < 10) {
    Serial.print('0');
  }
  Serial.print(hour());
  Serial.print(':');
  if (minute() < 10) {
    Serial.print('0');
  }
  Serial.print(minute());
  Serial.print(':');
  if (second() < 10) {
    Serial.print('0');
  }
  Serial.print(second());
  Serial.println();
}