Hello,
here is a code-example and democode that demonstrates how to connect to a WiFi and how to synchronise with a NTP time server
/* Example Demo-Code for ESP8266 and ESP32
Showing how to
- organise code well structured into functions
- connecting to a WiFi
- synchronise time with an NTP-server
- if connecting fails how to scan and print available WiFi-networks
- how to use minuteOfDay and secondOfDay which make it easier to compare
- the actual time with a certain point of time
- a tricky way to use the serial monitor similar to a LC-Display
- non-blocking timing based on function millis() with a helper-function
- how to print a timestamp when the code was compiled
written by user StefanL38
*/
#if defined(ESP32)
#include <WiFi.h>
char deviceType[] = "ESP32";
#else
#include <ESP8266WiFi.h>
char deviceType[] = "ESP8266";
#endif
unsigned long MyTestTimer = 0; // variables MUST be of type unsigned long
const byte OnBoard_LED = 2;
int connectCounter = 0;
int NoOfWiFis;
long minuteOfDay;
long secondOfDay;
const char *ssid = "your SSID";
const char *password = "your password";
const char dayOfWeek[][16] = {"sunday",
"monday",
"tuesday",
"wednesday",
"thursday",
"friday",
"saturday"
};
// a lot of home-wlan-routers can be used as a NTP-server too
const char* ntpServer = "fritz.box";
const long gmtOffset_sec = 0;
const int daylightOffset_sec = 7200;
#include <time.h> // time() ctime()
time_t now; // this is the epoch
tm myTimeInfo; // the structure tm holds time information in a more convient way
int Year;
int Month;
int Day;
int Hour;
int Minute;
int Second;
int DayIndex;
void updateMyTimeVars() {
Year = myTimeInfo.tm_year + 1900; // years since 1900
Month = myTimeInfo.tm_mon + 1; // January = 0 (!)
Day = myTimeInfo.tm_mday;
Hour = myTimeInfo.tm_hour;
Minute = myTimeInfo.tm_min;
Second = myTimeInfo.tm_sec;
DayIndex = myTimeInfo.tm_wday;
}
void clearSerialMonitor() {
for (int i = 0; i < 50; i++) {
Serial.println(); // print 50 empty lines
}
}
void showTime() {
time(&now); // read the current time
localtime_r(&now, &myTimeInfo); // update the structure tm with the current time
updateMyTimeVars();
Serial.print("year:");
Serial.print(Year);
Serial.print(" month:");
if (Month < 10) {
Serial.print("0");
}
Serial.print(Month);
Serial.print(" day:");
if (Day < 10) {
Serial.print("0");
}
Serial.print(Day); // day of month
Serial.print(" hour:");
if (Hour < 10) {
Serial.print("0");
}
Serial.print(Hour); // hours since midnight 0-23
Serial.print(" min:");
if (Minute < 10) {
Serial.print("0");
}
Serial.print(Minute); // minutes after the hour 0-59
Serial.print(" sec:");
if (Second < 10) {
Serial.print("0");
}
Serial.print(Second); // seconds after the minute 0-61*
Serial.print(" DayIndex:");
Serial.print(DayIndex); // days since Sunday 0-6
Serial.print(" name of day ");
Serial.print(dayOfWeek[DayIndex]);
minuteOfDay = Hour * 60 + Minute;
secondOfDay = Hour * 3600 + Minute * 60 + Second;
Serial.println();
Serial.println();
Serial.print("minuteOfDay ");
Serial.print(minuteOfDay);
Serial.print(" secondOfDay ");
Serial.print(secondOfDay);
// 12 hours 4 minutes 59 seconds = 12:04:59
if (secondOfDay < (12 * 3600 + 4 * 60 + 59) ) {
Serial.println(" actual time is before 12:04:59");
}
else {
Serial.println(" actual time is AFTER 12:04:59");
}
Serial.println();
Serial.println();
}
void connectToWifi() {
Serial.print("try connecting to ");
Serial.println(ssid);
WiFi.persistent(false);
WiFi.mode(WIFI_STA);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
yield(); // very important to have this function call to enable backround-processes
BlinkHeartBeatLED(OnBoard_LED, 333);
if ( TimePeriodIsOver(MyTestTimer, 500) ) {
Serial.print(".");
connectCounter++;
if (connectCounter % 20 == 0) {
Serial.println();
}
}
if (connectCounter > 120) {
break;
}
}
if (WiFi.status() == WL_CONNECTED) {
Serial.print("\n connected.");
Serial.println(WiFi.localIP() );
}
else {
Serial.print("\n unable to connect to WiFi with name #");
Serial.print(ssid);
Serial.println("#");
ScanWiFis();
Serial.print("\n code stopped with while(true) yield() ");
while (true) {
yield();
}
}
}
void ScanWiFis() {
int WiFiIdx;
Serial.println("Startscanning for networks");
NoOfWiFis = WiFi.scanNetworks();
Serial.println("scanning done List of SSIDs");
Serial.print("found number of networks ");
Serial.println(NoOfWiFis);
for (WiFiIdx = 0; WiFiIdx < NoOfWiFis; WiFiIdx++) {
// Print SSID and RSSI for each network found
Serial.print(WiFiIdx);
Serial.print(" #");
Serial.print( String( WiFi.SSID(WiFiIdx) ) );
Serial.print("# RSSI ");
Serial.print( String (WiFi.RSSI(WiFiIdx)) );
Serial.print(" dB");
Serial.println();
}
}
void synchroniseWith_NTP_Time() {
Serial.print("configTime uses ntpServer ");
Serial.println(ntpServer);
configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
Serial.print("synchronising time");
while (myTimeInfo.tm_year + 1900 < 2000 ) {
time(&now); // read the current time
localtime_r(&now, &myTimeInfo);
BlinkHeartBeatLED(OnBoard_LED, 100);
delay(100);
Serial.print(".");
}
Serial.print("\n time synchronsized \n");
showTime();
}
void PrintFileNameDateTime() {
Serial.println( F("Code running comes from file ") );
Serial.println(__FILE__);
Serial.print( F(" compiled ") );
Serial.print(__DATE__);
Serial.print( F(" ") );
Serial.println(__TIME__);
}
boolean TimePeriodIsOver (unsigned long & periodStartTime, unsigned long TimePeriod) {
unsigned long currentMillis = millis();
if ( currentMillis - periodStartTime >= TimePeriod )
{
periodStartTime = currentMillis; // set new expireTime
return true; // more time than TimePeriod) has elapsed since last time if-condition was true
}
else return false; // not expired
}
void BlinkHeartBeatLED(int IO_Pin, int BlinkPeriod) {
static unsigned long MyBlinkTimer;
pinMode(IO_Pin, OUTPUT);
if ( TimePeriodIsOver(MyBlinkTimer, BlinkPeriod) ) {
digitalWrite(IO_Pin, !digitalRead(IO_Pin) );
}
}
void setup() {
Serial.begin(115200);
delay(2000);
Serial.println("\n Setup-Start \n");
PrintFileNameDateTime();
connectToWifi();
synchroniseWith_NTP_Time();
}
void loop() {
BlinkHeartBeatLED(OnBoard_LED, 100);
if ( TimePeriodIsOver(MyTestTimer, 1000) ) {
clearSerialMonitor();
showTime();
}
}best regards Stefan