ESP32 NTP Time Synchronization with LCD Display

In today’s interconnected world, precise time synchronization is crucial for various applications. The “ESP32 NTP Time Synchronization with LCD Display” project combines two essential functions: network time protocol (NTP) synchronization and real-time data visualization through an LCD display. Leveraging the ESP32 microcontroller’s ability to connect to Internet servers via NTP ensures accurate timekeeping. Additionally, the LCD display provides a user-friendly interface for displaying synchronized time data in real-time, enhancing usability and accessibility.

The project aims to create an efficient system capable of NTP synchronization and delivering exact time. The system architecture involves connecting to a WiFi network, retrieving time data from NTP servers, and displaying the synchronized time on the LCD screen. This integration illuminates the significance of NTP synchronization, laying the groundwork for its application in ESP32-based systems. Emphasis is placed on developing comprehensive code that precisely controls synchronization and keeps the LCD display updated with the latest time. Reliability, efficiency, and compatibility are prioritized, alongside a modular approach for seamless integration into ESP32-based projects requiring precise timekeeping capabilities.

Components:

Connections:

Connection based on the video..

  1. External Power Supply Connection:
    • Use a 5V 1A power supply and connect it directly to the female power adapter.
    • Connect two male-to-male jumper wires to the positive and negative terminals of the female power adapter.
    • Connect the other ends of these jumper wires to the positive and negative rails of a breadboard.
  2. Powering the ESP32 Module:
    • To power the ESP32 module, use two male-to-female jumper wires.
    • Connect the VIN pin of the ESP32 to the positive rail of the breadboard.
    • Connect the GND pin of the ESP32 to the negative rail of the breadboard.
  3. LCD Display Connection:
    • Connect the VCC pin of the LCD I2C 1602 display to the 3.3V pin of the ESP32 module.
    • Connect the GND pin of the LCD display to the GND pin of the ESP32 module.
    • Connect the SDA pin of the LCD display to pin D21 of the ESP32 module.
    • Connect the SCL pin of the LCD display to pin D22 of the ESP32 module.
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Notes:

  • Install the “Esp32” in board manager (click the board NodeMCU-32S)
  • Install the LiquidCrystal_I2C in the Library Manager

Code:

Below is a structured approach to the code for the “ESP32 NTP Time Synchronization with LCD Display” project:

#include <WiFi.h>
#include "time.h"
#include "sntp.h"
#include <LiquidCrystal_I2C.h>

//0x3F or 0x27
LiquidCrystal_I2C lcd(0x3F, 16, 2);   //LCD Object

const char* ssid       = "CIRCUIT.ROCKS";
const char* password   = "abcdefghij";

const char* ntpServer1 = "pool.ntp.org";
const char* ntpServer2 = "time.nist.gov";
const long  gmtOffset_sec = 3600;
const int   daylightOffset_sec = 3600;

void printLocalTime()
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    Serial.println("No time available (yet)");
    return;
  }

  //Display Date & Time
  lcd.clear();
  lcd.print(&timeinfo, "%B %d %Y");    //November 22 2022
  lcd.setCursor(0,1);
  lcd.print(&timeinfo, "%A,%H:%M:%S"); //Tuesday 10:30:05

}

// Callback function (get's called when time adjusts via NTP)
void timeavailable(struct timeval *t)
{
  Serial.println("Got time adjustment from NTP!");
  printLocalTime();
}

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

  // Setup LCD with backlight and initialize
  lcd.init();
  lcd.backlight();

  // set notification call-back function
  sntp_set_time_sync_notification_cb( timeavailable );

  /**
   * NTP server address could be aquired via DHCP,
   *
   * NOTE: This call should be made BEFORE esp32 aquires IP address via DHCP,
   * otherwise SNTP option 42 would be rejected by default.
   * NOTE: configTime() function call if made AFTER DHCP-client run
   * will OVERRIDE aquired NTP server address
   */
  sntp_servermode_dhcp(1);    // (optional)

  /**
   * This will set configured ntp servers and constant TimeZone/daylightOffset
   * should be OK if your time zone does not need to adjust daylightOffset twice a year,
   * in such a case time adjustment won't be handled automagicaly.
   */
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer1, ntpServer2);

  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  lcd.clear();
  lcd.print("Connecting to ");
  lcd.setCursor(0, 1);
  lcd.print(ssid);
  delay(1000);

  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
  }
  Serial.println(" CONNECTED");
  lcd.clear();
  lcd.print("CONNECTED");
  delay(2000);
}

void loop()
{
  delay(1000);
  printLocalTime();     // it will take some time to sync time :)
}

This structured code follows a step-by-step approach:

  1. Wi-Fi Setup: Connects to the specified Wi-Fi network.
  2. NTP Server Configuration: Sets up the NTP client with the chosen server and time zone offset.
  3. Initialization: Initializes the LCD display.
  4. Main Loop:
    • Updates and displays the time in a continuous loop.
  5. Connect to Wi-Fi Function: Handles connecting to the specified Wi-Fi network.
  6. Update Time Function: Initializes the NTP client and updates the time.
  7. Display Time Function: Updates the time and formats it for display on the LCD.
  8. Format Time Function: Formats the time according to the desired format.
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Troubleshooting:

  • Verify that the library is installed correctly in your Arduino IDE.
  • Ensure all connections are correctly made according to the instructions.
  • If the LCD display is not lighting up or showing any characters, check the power supply connections and voltage levels. ( Note: Try to connect the VCC pin to the positive rail and GND pin to the negative rail of Breadboard directly to ensure sufficient power from the external power supply).
  • If the text on the LCD display is not showing correctly, use a small screwdriver to carefully turn the potentiometer. Turning it clockwise or counterclockwise should change the contrast of the characters on the display.
  • Look for any error messages or warnings displayed in the Arduino IDE’s Serial Monitor.

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