ESP8266 Community Forum

Posted: **Mon Dec 11, 2017 6:22 pm**

I am wanting to use an esp8266 12e with a RTC and LCD 20x4 display. I want my relay to work by time of day. I am looking for examples of i2c working with the clock and the lcd or another way to get the clock and LCD in my projects. Thanks again for the help

Sprinkfitter

Posted: **Mon Dec 11, 2017 10:26 pm**

One problem I had with using the I2C 20x4 lcd with 3.3v powered processors is that the lcd (with the I2C PCF8574) is powered from 5 volts and the high level output from the 3.3 v processor often is not high enough for the PCF8574. I include a 3-5 volt level converter to make the levels compatible.

My preference is the DS3231 for the RTC. 3.3 volt compatible.

One other display option I have used with the ESP8266 is the 128x64 OLED.

IMG3.jpg

IMG_1.jpg

Posted: **Mon Dec 11, 2017 11:46 pm**

I looked into my RTC directory and I found a program that was interesting. I added I2C LCD to it. It is an ugly hack but it works. Reads the time from the RTC and displays it on the LCD. There also is a web page that can be used to change the time. Not in English but easy enough to figure out.

I'm not sure where the original program was from.
maybe here - https://jmloureiro77.blogspot.ca/2017/0 ... s3231.html

https://github.com/Makuna/Rtc RTC library
https://github.com/agnunez/ESP8266-I2C-LCD1602 I2C LCD library

I have a led on GPIO15,
I2C lines are on 0 and 1. see code

I use a supercap in place of the battery for the RTC.

Code: Select all

//  I'm not sure where the original program was from. 
// maybe here  -  https://jmloureiro77.blogspot.ca/2017/04/esp8266-rtc-ds3231.html
// https://github.com/Makuna/Rtc   RTC library
// https://github.com/agnunez/ESP8266-I2C-LCD1602   I2C LCD library  

// CONNECTIONS:
// DS3231 SDA --> SDA=============nodemcu D1
// DS3231 SCL --> SCL=============nodemcu D2
// DS3231 VCC --> 3.3v or 5v
// DS3231 GND --> GND

#include <ESP8266WiFi.h>
//#include <WiFiClient.h>
#include <ESP8266WebServer.h>
#include <ESP8266mDNS.h>
#include <ESP8266HTTPUpdateServer.h>

#include <Wire.h> // must be included here so that Arduino library object file references work
#include <RtcDS3231.h>
RtcDS3231<TwoWire> Rtc(Wire);

#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4); //I2C address, columns, lines

const int ledPin =  15;              // the number of the LED pin
// Variables will change:
int ledState = LOW;             // ledState used to set the LED

const char* host = "esp8266";

const char* ssid = "2WIRE865";
const char* password = "xxxxxxxxxxxxxxx";

// Generally, you should use "unsigned long" for variables that hold time
// The value will quickly become too large for an int to store
unsigned long previousMillis = 0;        // will store last time LED was updated

// constants won't change:
const long interval = 1000;           // interval at which to blink (milliseconds)


char datestring[20];
String message, javaScript, XML;

ESP8266WebServer httpServer(80);
ESP8266HTTPUpdateServer httpUpdater;

RtcDateTime now;

//=============================================================================================
void buildJavascript() {
  //=============================================================================================
  javaScript = "<SCRIPT>\n";
  javaScript += "var xmlHttp=createXmlHttpObject();\n";

  javaScript += "function createXmlHttpObject(){\n";
  javaScript += " if(window.XMLHttpRequest){\n";
  javaScript += "    xmlHttp=new XMLHttpRequest();\n";
  javaScript += " }else{\n";
  javaScript += "    xmlHttp=new ActiveXObject('Microsoft.XMLHTTP');\n"; // code for IE6, IE5
  javaScript += " }\n";
  javaScript += " return xmlHttp;\n";
  javaScript += "}\n";

  javaScript += "function process(){\n";
  javaScript += " if(xmlHttp.readyState==0 || xmlHttp.readyState==4){\n";
  javaScript += "   xmlHttp.open('PUT','xml',true);\n";
  javaScript += "   xmlHttp.onreadystatechange=handleServerResponse;\n"; // no brackets?????
  javaScript += "   xmlHttp.send(null);\n";
  javaScript += " }\n";
  javaScript += " setTimeout('process()',1000);\n";
  javaScript += "}\n";

  javaScript += "function handleServerResponse(){\n";
  javaScript += " if(xmlHttp.readyState==4 && xmlHttp.status==200){\n";
  javaScript += "   xmlResponse=xmlHttp.responseXML;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rYear');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('year').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rMonth');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('month').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rDay');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('day').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rHour');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('hour').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rMinute');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('minute').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rSecond');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('second').innerHTML=message;\n";

  javaScript += "   xmldoc = xmlResponse.getElementsByTagName('rTemp');\n";
  javaScript += "   message = xmldoc[0].firstChild.nodeValue;\n";
  javaScript += "   document.getElementById('temp').innerHTML=message;\n";

  javaScript += " }\n";
  javaScript += "}\n";
  javaScript += "</SCRIPT>\n";
}
//=============================================================================================
void buildXML() {
  //=============================================================================================
  RtcDateTime now = Rtc.GetDateTime();
  RtcTemperature temp = Rtc.GetTemperature();
  XML = "<?xml version='1.0'?>";
  XML += "<t>";
  XML += "<rYear>";
  XML += now.Year();
  XML += "</rYear>";
  XML += "<rMonth>";
  XML += now.Month();
  XML += "</rMonth>";
  XML += "<rDay>";
  XML += now.Day();
  XML += "</rDay>";
  XML += "<rHour>";
  if (now.Hour() < 10) {
    XML += "0";
    XML += now.Hour();
  } else {
    XML += now.Hour();
  }
  XML += "</rHour>";
  XML += "<rMinute>";
  if (now.Minute() < 10) {
    XML += "0";
    XML += now.Minute();
  } else {
    XML += now.Minute();
  }
  XML += "</rMinute>";
  XML += "<rSecond>";
  if (now.Second() < 10) {
    XML += "0";
    XML += now.Second();
  } else {
    XML += now.Second();
  }
  XML += "</rSecond>";
  XML += "<rTemp>";
  XML += temp.AsFloat();
  XML += "</rTemp>";
  XML += "</t>";
}
//=============================================================================================
void handleRoot() {
  //=============================================================================================
  buildJavascript();
  IPAddress ip = WiFi.localIP();
  String ipStr = (String(ip[0]) + '.' + String(ip[1]) + '.' + String(ip[2]) + '.' + String(ip[3]));

  // message="<!DOCTYPE HTML>\n";
  message = "<html>";
  //  message = "<html><head><meta http-equiv='refresh' content='5'/>";
  message = "<head>";
  message = javaScript;
  message += "<title>ESP8266 Demo</title>";
  message += "<style> body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }";
  message += "h1 {text-align:center;}";
  message += "h2 {text-align:center;}";
  message += "p {text-align:center;}";
  message += "table.center { width:80%; margin-left:10%; margin-right:10%;}";
  message += "</style>";
  message += "  </head>";
  message += "  <body onload='process()'>";
  message += "<table class='center'>";
  message += "  <tr>";
  message += "    <th>";
  message += "<h1>Fecha y Hora</h1>";
  message += "    </th> ";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";
  message += "    </td>";
  message += "  </tr>";


  message += "  <tr>";
  message += "    <td align='center'>";
  message += "<A id='year'></A>/<A id='month'></A>/<A id='day'></A>   <A id='hour'></A>:<A id='minute'></A>:<A id='second'></A><BR>";
  message += "    </td>";
  message += "  </tr>";

  message += "  <tr>";
  message += "    <td align='center'>";
  message += "Temp =<A id='temp'></A>C<BR>";
  message += "    </td>";
  message += "  </tr>";

  message += "  <tr>";
  message += "    <td>";
  message += "<H2><a href='/setTime'>Cambiar fecha y hora</a></H2>";
  message += "    </td>";
  message += "  </tr>";

  message += "  <tr>";
  message += "    <td align='center'>";
  message += "<BR>IP  ";
  message += ipStr;
  message += "    </td>";
  message += "  </tr>";
  message += "</table>";

  message += "<BR>";

  message += "";

  message += "</body></html>";

  httpServer.send ( 404 , "text/html", message );
}

//=============================================================================================
void setTime() {
  //=============================================================================================
  buildJavascript();
  // message="<!DOCTYPE HTML>\n";
  message = "<html>";
  //  message = "<html><head><meta http-equiv='refresh' content='5'/>";
  message = "<head>";
  message = javaScript;
  message += "<title>ESP8266 set time</title>";
  message += "<style> body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }";
  message += "h1 {text-align:center;}";
  message += "h2 {text-align:center;}";
  message += "p {text-align:center;}";
  message += "table.center { width:80%; margin-left:10%; margin-right:10%;}";
  message += "</style>";
  message += "  </head>";
  message += "  <body onload='process()'>";/////////////////////////////////////////

  message += "";

  message += "<table class='center'>";
  message += "  <tr>";
  message += "    <th>";
  message += "<h1>Cambiar fecha y hora</h1>";
  message += "    </th> ";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";
  message += "Fecha Atual  ";
  message += " <BR>   </td>";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";
  message += "<A id='year'></A>/<A id='month'></A>/<A id='day'></A><BR>";
  message += "    </td>";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";

  message += "<form >";
  message += "Pon fecha posterior a 2017-03-20<br><br>";
  message += "<input type='date' name='date' min='2017-03-20' style='height:75px; width:200px'><br><br>";
  message += "<input type='submit' value='Actualizar Fecha' style='height:75px; width:200px'> ";
  message += "</form>";


  message += "    </td>";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";
  message += "Hora Actal<BR><A id='hour'></A>:<A id='minute'></A>:<A id='second'></A><BR><BR>";
  message += "    </td>";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td align='center'>";
  message += "<form >";
  message += "Nueva hora<br>";
  message += "<input type='TIME' name='time' style='height:75px; width:200px'><br><br>";
  message += "<input type='submit' value='Actualizar Hora' style='height:75px; width:200px'> ";
  message += "</form>";
  message += "    </td>";
  message += "  </tr>";
  message += "  <tr>";
  message += "    <td>";
  message += "<H2><a href='/'>ATRAS</a></H2>";
  message += "    </td>";
  message += "  </tr>";
  message += "</table>";


  message += "";

  message += "</body></html>";

  httpServer.send ( 404 , "text/html", message );

  // Fecha--------------------------------------------------------------------
  if (httpServer.hasArg("date")) {

    uint16_t ano;
    uint8_t mes;
    uint8_t dia;
    Serial.print("ARGdate");
    Serial.println(httpServer.arg("date"));
    String sd = httpServer.arg("date");
    String lastSd;
    //   int someInt = someChar - '0';
    ano = ((sd[0] - '0') * 1000) + ((sd[1] - '0') * 100) + ((sd[2] - '0') * 10) + (sd[3] - '0');
    mes = ((sd[5] - '0') * 10) + (sd[6] - '0');
    dia = ((sd[8] - '0') * 10) + (sd[9] - '0');
    if (sd != lastSd) {
      RtcDateTime now = Rtc.GetDateTime();
      uint8_t hour = now.Hour();
      uint8_t minute = now.Minute();
      Rtc.SetDateTime(RtcDateTime(ano, mes, dia, hour, minute, 0));
      lastSd = sd;
    }
    // Serial.println(fa);

    httpServer.send ( 404 , "text", message );
  }//if has date
  // Hora ------------------------------------------------
  if (httpServer.hasArg("time")) {
    Serial.println(httpServer.arg("time"));
    String st = httpServer.arg("time");
    String lastSt;
    //   Serial.print("st ");
    //   Serial.println(st);
    //int someInt = someChar - '0';
    uint8_t hora = ((st[0] - '0') * 10) + (st[1] - '0');
    uint8_t minuto = ((st[3] - '0') * 10) + (st[4] - '0');
    if (st != lastSt) {
      RtcDateTime now = Rtc.GetDateTime();
      uint16_t year = now.Year();
      uint8_t month = now.Month();
      uint8_t day = now.Day();
      Rtc.SetDateTime(RtcDateTime(year, month, day, hora, minuto, 0));
      lastSt = st;
    }
    httpServer.send ( 404 , "text", message );

  }//if has time
}
//=============================================================================================
void handleXML() {
  //=============================================================================================
  buildXML();
  httpServer.send(200, "text/xml", XML);
}
//=============================================================================================
void handleNotFound() {
  //=============================================================================================
  String message = "<html><head>";
  message += "<title>ESP8266 Not Found</title>";
  message += "<style> body { background-color: #cccccc; font-family: Arial, Helvetica, Sans-Serif; Color: #000088; }";
  message += "h1 {text-align:center;}";
  message += "h2 {text-align:center;}";
  message += "</style>";
  message += "  </head>";
  message += "  <body>";
  message += "<table style='width:80%'>";
  message += "<tr>";//fila
  message += "<th>";//columna encavezado
  message += "<h1>Not Found</h1>";
  message += "</th>";
  message += "<tr>";//fila 2
  message += "<td>";//columna normal
  message += "<H2><a href='/'>Back</a></H2>";
  message += "<td>";
  message += "</tr>";
  message += "</table>";
  message += "</body></html>";
  message += "";

  httpServer.send ( 404 , "text", message );
}

//=============================================================================================
void setup(void) {
  //=============================================================================================
  pinMode(ledPin, OUTPUT);
  
  Serial.begin(115200);
  Serial.println();
  Serial.println("Booting Sketch...ESP_RTC3231.ino");

  lcd.begin(0, 2);        // In ESP8266-01, SDA=0, SCL=2
  lcd.clear();
  lcd.setCursor(0, 3);    // column 0, row 0
  lcd.print("lcd setup");

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.waitForConnectResult() != WL_CONNECTED) {
    WiFi.begin(ssid, password);
    Serial.println("WiFi failed, retrying.");
  }
  if ( MDNS.begin ( "host" ) ) {
    Serial.println ( "MDNS responder started" );
  }
  //MDNS.begin(host);

  httpUpdater.setup(&httpServer);


  httpServer.on ( "/", handleRoot );
  httpServer.on ( "/setTime", setTime );
  httpServer.on ( "/xml", handleXML) ;


  httpServer.onNotFound ( handleNotFound );

  Serial.println ( "HTTP server started" );

  httpServer.begin();

  MDNS.addService("http", "tcp", 80);
  Serial.printf("HTTPUpdateServer ready!\n Open http://%s.local/update in your browser\n", host);

  Serial.println(WiFi.localIP());
  Serial.println("-----------------------");

  // RTC ---------------------------------------------------------------------------------------
  Rtc.Begin();

  // if you are using ESP-01 then uncomment the line below to reset the pins to
  // the available pins for SDA, SCL
  Wire.begin(0, 2); // due to limited pins, use pin 0 and 2 for SDA, SCL

  //   RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__);
  if (!Rtc.GetIsRunning()) {
    //     Serial.println("RTC was not actively running, starting now");
    Rtc.SetIsRunning(true);
  }
  //RtcDateTime now = Rtc.GetDateTime();
  // never assume the Rtc was last configured by you, so
  // just clear them to your needed state
  Rtc.Enable32kHzPin(false);
  Rtc.SetSquareWavePin(DS3231SquareWavePin_ModeNone);

  lcd.setCursor(0, 3);    // column 0, row 0
  lcd.print("           ");  
}

//=============================================================================================
void loop(void) {
  //=============================================================================================
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval) {
    // save the last time you blinked the LED
    previousMillis = currentMillis;

    // if the LED is off turn it on and vice-versa:
    if (ledState == LOW) {
      ledState = HIGH;
    } else {
      ledState = LOW;
    }

    // set the LED with the ledState of the variable:
    digitalWrite(ledPin, ledState);

    // RTC ---------------------------------------------------------------------------------------
    RtcDateTime now = Rtc.GetDateTime();
    printDateTime(now);
    Serial.println();

    RtcTemperature temp = Rtc.GetTemperature();
    Serial.print(temp.AsFloat());
    Serial.println("C");

/*
    lcd.setCursor(0, 0);    // column 0, row 0
    lcd.println(dt.Hour());
    lcd.println(":");
    lcd.println(dt.Minute());
    lcd.println(":");
    lcd.println(dt.Second());
    */
  }

  httpServer.handleClient();
}

//=======================================================

#define countof(a) (sizeof(a) / sizeof(a[0]))

void printDateTime(const RtcDateTime& dt)
{
  char datestring[20];

  snprintf_P(datestring,
             countof(datestring),
             PSTR("%02u/%02u/%04u %02u:%02u:%02u"),
             dt.Month(),
             dt.Day(),
             dt.Year(),
             dt.Hour(),
             dt.Minute(),
             dt.Second() );
  Serial.print(datestring);

    lcd.setCursor(0, 0);    // column 0, row 0
    lcd.print(datestring);
    lcd.print("  ");
}
//----------------------------------------------------------

Posted: **Tue Dec 12, 2017 12:08 am**

Here is a simpler program but derived from the same RTC library. Also puts time on LCD. No WiFi.

Code: Select all

// Rtc_by_Makuna library


// CONNECTIONS:
// DS3231 SDA --> SDA
// DS3231 SCL --> SCL
// DS3231 VCC --> 3.3v or 5v
// DS3231 GND --> GND

#if defined(ESP8266)
#include <pgmspace.h>
#else
#include <avr/pgmspace.h>
#endif


#include <Wire.h> // must be included here so that Arduino library object file references work
#include <RtcDS3231.h>
RtcDS3231<TwoWire> Rtc(Wire);

#include <LiquidCrystal_I2C.h>

  LiquidCrystal_I2C lcd(0x27,20,4); // Check I2C address of LCD, normally 0x27 or 0x3F


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

    Serial.print("compiled: ");
    Serial.print(__DATE__);
    Serial.println(__TIME__);
    
  lcd.begin(0,2);      // In ESP8266-01, SDA=0, SCL=2               
  lcd.backlight();
  lcd.home();                // At column=0, row=0
  lcd.print("Starting");   
 //   lcd.setCursor(0, 1);
    
    //--------RTC SETUP ------------
    Rtc.Begin();

    // if you are using ESP-01 then uncomment the line below to reset the pins to
    // the available pins for SDA, SCL
    Wire.begin(0, 2); // due to limited pins, use pin 0 and 2 for SDA, SCL

    RtcDateTime compiled = RtcDateTime(__DATE__, __TIME__);
    printDateTime(compiled);
    Serial.println();

    if (!Rtc.IsDateTimeValid()) 
    {
        // Common Cuases:
        //    1) first time you ran and the device wasn't running yet
        //    2) the battery on the device is low or even missing

        Serial.println("RTC lost confidence in the DateTime!");

        // following line sets the RTC to the date & time this sketch was compiled
        // it will also reset the valid flag internally unless the Rtc device is
        // having an issue

        Rtc.SetDateTime(compiled);
    }

    if (!Rtc.GetIsRunning())
    {
        Serial.println("RTC was not actively running, starting now");
        Rtc.SetIsRunning(true);
    }

    RtcDateTime now = Rtc.GetDateTime();
    if (now < compiled) 
    {
        Serial.println("RTC is older than compile time!  (Updating DateTime)");
        Rtc.SetDateTime(compiled);
    }
    else if (now > compiled) 
    {
        Serial.println("RTC is newer than compile time. (this is expected)");
    }
    else if (now == compiled) 
    {
        Serial.println("RTC is the same as compile time! (not expected but all is fine)");
    }

    // never assume the Rtc was last configured by you, so
    // just clear them to your needed state
    Rtc.Enable32kHzPin(false);
    Rtc.SetSquareWavePin(DS3231SquareWavePin_ModeNone); 
}

//===================================================
void loop () 
{
    if (!Rtc.IsDateTimeValid()) 
    {
        // Common Cuases:
        //    1) the battery on the device is low or even missing and the power line was disconnected
        Serial.println("RTC lost confidence in the DateTime!");
    }

    RtcDateTime now = Rtc.GetDateTime();
    printDateTime(now);
    Serial.println();

    RtcTemperature temp = Rtc.GetTemperature();
    Serial.print(temp.AsFloat());
    Serial.println("C");


    LCDprintDateTime(now);
    
    lcd.setCursor(0, 2);    
    lcd.print("  ");    
    lcd.print(temp.AsFloat());
    lcd.print("C");

    delay(1000); // one seconds
}

//====================================================
#define countof(a) (sizeof(a) / sizeof(a[0]))

void printDateTime(const RtcDateTime& dt)
{
    char datestring[20];

    snprintf_P(datestring, 
            countof(datestring),
            PSTR("%02u/%02u/%04u %02u:%02u:%02u"),
            dt.Month(),
            dt.Day(),
            dt.Year(),
            dt.Hour(),
            dt.Minute(),
            dt.Second() );
    Serial.print(datestring);
}

//-----------------------------------------------------------
void LCDprintDateTime(const RtcDateTime& dt)
{
    char datestring[20];

    snprintf_P(datestring, 
            countof(datestring),
            PSTR("%02u/%02u/%04u %02u:%02u:%02u"),
            dt.Month(),
            dt.Day(),
            dt.Year(),
            dt.Hour(),
            dt.Minute(),
            dt.Second() );


    lcd.setCursor(0, 1);
    lcd.print(datestring);
}

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RTC with LCD 20x4 Display

RTC with LCD 20x4 Display

Re: RTC with LCD 20x4 Display

Re: RTC with LCD 20x4 Display

Re: RTC with LCD 20x4 Display