Showing posts with label Synchronize. Show all posts
Showing posts with label Synchronize. Show all posts
2017/05/14
NTP Server Synchronized LCD DS1307 RTC Clock
Requirements:
1. Arduino Uno R3
2. RTC (DS1307) Sensor Shield
3. W5100 Ethernet Shield
4. LCD Keypad Shield
Schetch:
/*
* NTPSynchronizedRTC20170514.ino
*/
#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);
char dayOfWeek[9][4] = {"", "SUN", "MON", "TUE", "WED", "THU", "FRI", "SAT"};
time_t t;
int displayAtSecond;
// timeZoneOffset = (Time Zone) * 3600L eg. (+8) * 3600L = 28800L for Taipei, Taiwan
const long timeZoneOffset = 28800L;
// sync to NTP server every "ntpSyncInterval" seconds, set to 1 hour or more to be reasonable
unsigned long ntpSyncInterval = 3600;
// adjust the sync latency with computer NTP client in seconds
unsigned long syncLatency = 0;
// 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(192, 168, 1, 123); // LAN 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;
// keep track of how long ago we updated the NTP server
unsigned long ntpLastUpdate = 0;
void setup() {
Serial.begin(115200);
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) >= ntpSyncInterval) {
ntpSyncDS1307();
// clear seconds displayed once a second when sync is needed, cause seconds blink to notify checking the network status
lcd.setCursor(9, 1);
lcd.print(" ");
}
// for LCD shield to disp date, day of the week, time and temperature once a second
t = now();
if (displayAtSecond != second(t)) {
digitalClockDisplay();
displayAtSecond = second(t);
}
}
void digitalClockDisplay(){
// digital clock display of the time
dateDisplay();
weekdayDisplay();
timeDisplay();
// display seconds since last NTP update
lcd.setCursor(9, 1);
lcd.print(now()-ntpLastUpdate);
// Serial.print(now());
// Serial.print(" ");
// Serial.println(ntpLastUpdate);
}
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 ntpSyncDS1307() {
sendNTPpacket(timeServer); // send an NTP packet to a time server
// wait to see if a replay is available
delay(100);
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();
// clear seconds displayed once ntp sync succeeded
lcd.setCursor(9, 1);
lcd.print(" ");
}
}
// 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 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();
}
2014/11/09
Arduino RF Wireless Message Display Using I2C LCD Keypad Shield
The function of this sketch is same as the sketch posted on May. 11, 2014, but using I2C LCD Keypad Shield as the output device.
Sketch
/*
SimpleReceiveI2CLCD
This sketch displays text strings received using VirtualWire
Connect the Receiver data pin to Arduino pin 11
Modified by Befun Hung on Nov. 09, 2014
Use I2C LCD Keypad Shield as the output
*/
#include <VirtualWire.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// #define BACKLIGHT_PIN 13
LiquidCrystal_I2C lcd(0x20); //Set the LCD I2C address
// LiquidCrystal_I2C lcd(0x38, BACKLIGHT_PIN, POSITIVE);
byte message[VW_MAX_MESSAGE_LEN]; // a buffer to store the incoming messages
byte messageLength = VW_MAX_MESSAGE_LEN; // the size of the message
unsigned long counter = 1;
void setup()
{
// pinMode(BACKLIGHT_PIN, OUTPUT);
// digitalWrite(BACKLIGHT_PIN, HIGH);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2); //initialize the lcd
// Print a message to the LCD.
lcd.home(); //go home
lcd.print("Device is ready!");
//
Serial.begin(9600);
Serial.println("Device is ready");
// Initialize the IO and ISR
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver
}
void loop()
{
if (vw_get_message(message, &messageLength)) // Non-blocking
{
lcd.clear();
Serial.print(counter);
Serial.print(": ");
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 0);
lcd.print(counter);
lcd.print(":");
lcd.setCursor(0,1);
for (int i = 0; i < messageLength; i++)
{
Serial.write(message[i]);
lcd.print(char(message[i]));
}
Serial.println();
counter++;
}
}
Sketch
/*
SimpleReceiveI2CLCD
This sketch displays text strings received using VirtualWire
Connect the Receiver data pin to Arduino pin 11
Modified by Befun Hung on Nov. 09, 2014
Use I2C LCD Keypad Shield as the output
*/
#include <VirtualWire.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
// #define BACKLIGHT_PIN 13
LiquidCrystal_I2C lcd(0x20); //Set the LCD I2C address
// LiquidCrystal_I2C lcd(0x38, BACKLIGHT_PIN, POSITIVE);
byte message[VW_MAX_MESSAGE_LEN]; // a buffer to store the incoming messages
byte messageLength = VW_MAX_MESSAGE_LEN; // the size of the message
unsigned long counter = 1;
void setup()
{
// pinMode(BACKLIGHT_PIN, OUTPUT);
// digitalWrite(BACKLIGHT_PIN, HIGH);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2); //initialize the lcd
// Print a message to the LCD.
lcd.home(); //go home
lcd.print("Device is ready!");
//
Serial.begin(9600);
Serial.println("Device is ready");
// Initialize the IO and ISR
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver
}
void loop()
{
if (vw_get_message(message, &messageLength)) // Non-blocking
{
lcd.clear();
Serial.print(counter);
Serial.print(": ");
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 0);
lcd.print(counter);
lcd.print(":");
lcd.setCursor(0,1);
for (int i = 0; i < messageLength; i++)
{
Serial.write(message[i]);
lcd.print(char(message[i]));
}
Serial.println();
counter++;
}
}
2014/05/11
Arduino RF Wireless Message Display
As I am building the RF wireless power socket for home automation, I need a stand along tool to display any wireless received message. During the lab, I use Arduino serial monitor to monitor the message received once a second, error always happens at different time point as following screen shot shows. After disconnecting the Arduino Uno from PC to monitor message received by using LCD keypad shield as a stand along system, the error condition gone.
The RF wireless message display can be used to display the time on the NTP synchronized RTC clock (my projects during Aug 2013), so no additional time adjustment at display side is needed.
Parts Used
1. Arduino Uno R3
2. cheaphousetek LCD Keypad Shield
3. RF Receiver (described in Arduino Cookbook 14.1)
Connection
1. Stack LCD Key Keypad Upon Arduino Uno R3
2. RF Receiver Data Pin - Arduino Uno D11
3. RF Receiver Vcc - Arduino Uno 5V
4. RF Receiver Gnd - Arduino Uno Gnd
Photo
The sketch runs correctly with output to LCD shield for 247,610 times.
Sketch
/*
SimpleReceiveLCD
This sketch displays text strings received using VirtualWire
Connect the Receiver data pin to Arduino pin 11
*/
#include <VirtualWire.h>
// include the library code:
#include <LiquidCrystal.h>
byte message[VW_MAX_MESSAGE_LEN]; // a buffer to store the incoming messages
byte messageLength = VW_MAX_MESSAGE_LEN; // the size of the message
unsigned long counter = 1;
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
void setup()
{
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");
lcd.clear();
Serial.begin(9600);
Serial.println("Device is ready");
// Initialize the IO and ISR
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver
}
void loop()
{
if (vw_get_message(message, &messageLength)) // Non-blocking
{
lcd.clear();
Serial.print(counter);
Serial.print(": ");
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 0);
lcd.print(counter);
lcd.print(":");
lcd.setCursor(0,1);
for (int i = 0; i < messageLength; i++)
{
Serial.write(message[i]);
lcd.print(char(message[i]));
}
Serial.println();
counter++;
}
}
The RF wireless message display can be used to display the time on the NTP synchronized RTC clock (my projects during Aug 2013), so no additional time adjustment at display side is needed.
Parts Used
1. Arduino Uno R3
2. cheaphousetek LCD Keypad Shield
3. RF Receiver (described in Arduino Cookbook 14.1)
Connection
1. Stack LCD Key Keypad Upon Arduino Uno R3
2. RF Receiver Data Pin - Arduino Uno D11
3. RF Receiver Vcc - Arduino Uno 5V
4. RF Receiver Gnd - Arduino Uno Gnd
Photo
The sketch runs correctly with output to LCD shield for 247,610 times.
Sketch
/*
SimpleReceiveLCD
This sketch displays text strings received using VirtualWire
Connect the Receiver data pin to Arduino pin 11
*/
#include <VirtualWire.h>
// include the library code:
#include <LiquidCrystal.h>
byte message[VW_MAX_MESSAGE_LEN]; // a buffer to store the incoming messages
byte messageLength = VW_MAX_MESSAGE_LEN; // the size of the message
unsigned long counter = 1;
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);
void setup()
{
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
// Print a message to the LCD.
lcd.print("hello, world!");
lcd.clear();
Serial.begin(9600);
Serial.println("Device is ready");
// Initialize the IO and ISR
vw_setup(2000); // Bits per sec
vw_rx_start(); // Start the receiver
}
void loop()
{
if (vw_get_message(message, &messageLength)) // Non-blocking
{
lcd.clear();
Serial.print(counter);
Serial.print(": ");
// set the cursor to column 0, line 1
// (note: line 1 is the second row, since counting begins with 0):
lcd.setCursor(0, 0);
lcd.print(counter);
lcd.print(":");
lcd.setCursor(0,1);
for (int i = 0; i < messageLength; i++)
{
Serial.write(message[i]);
lcd.print(char(message[i]));
}
Serial.println();
counter++;
}
}
2013/08/21
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);
}
}
2013/08/04
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();
}
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();
}
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