NTP Clock with ESP8266 and WS2812B 8×24 Pixel LED Matrix

Components Used:

• Microcontroller: ESP8266
• LED Matrix: WS2812B 8×24 Pixel Matrix
• Libraries Used:
  • ESP8266WiFi.h: For Wi-Fi connectivity
  • Adafruit_GFX.h: Core graphics library for drawing text and shapes
  • Adafruit_NeoMatrix.h: For controlling the NeoPixel matrix
  • time.h: For handling time functions

Code Overview:

This project connects an ESP8266 microcontroller to a WS2812B 8×24 LED matrix to display the current time using the Network Time Protocol (NTP). The time is displayed in HHMM format, with a flashing effect on two vertically aligned pixels.

To connect your ESP8266 to Wi-Fi, update the ssid and password in the code. Look for this part:

// WiFi credentials
const char* ssid = "YourWiFiNetworkName";  // Replace with your WiFi SSID
const char* password = "YourWiFiPassword"; // Replace with your WiFi password

Replace "YourWiFiNetworkName" with your actual Wi-Fi network name (SSID) and "YourWiFiPassword" with your actual Wi-Fi password, keeping the quotation marks.

The time offset for Indian Standard Time (IST) based on the Greenwich Mean Time (GMT) offset.

Since IST is GMT+5:30, the offset is calculated in seconds as follows:

• 5 hours = 5 * 60 * 60 = 18,000 seconds
• 30 minutes = 30 * 60 = 1,800 seconds
• Total = 18,000 + 1,800 = 19,800 seconds

So, this offset (19,800 seconds) adjusts the time to match IST when using an NTP server.

const long gmtOffset_sec = 19800;  // GMT offset for Indian Standard Time (IST) in seconds

Key Features:

• Wi-Fi Connectivity: Connects to a specified Wi-Fi network.
• NTP Time Synchronization: Retrieves and displays the current time based on the Indian Standard Time (IST).
• Flashing Effect: Two red LEDs flash as a separator on the display.
• Customizable Brightness: The matrix brightness can be adjusted.

Code Snippet:

#include <ESP8266WiFi.h>                // Include the ESP8266 WiFi library
#include <Adafruit_GFX.h>               // Core graphics library
#include <Adafruit_NeoMatrix.h>         // For NeoPixel Matrix
#include <time.h>                       // Include time library

#define DATA_PIN 2                     // Use GPIO 2 for the WS2812B Data line
#define MATRIX_WIDTH 24                // Width of the matrix (24)
#define MATRIX_HEIGHT 8                // Height of the matrix (8)
#define CHAR_WIDTH 6                   // Width of each character (approximation)

// WiFi credentials
const char* ssid = "YourWiFiNetworkName";  // Replace with your WiFi SSID
const char* password = "YourWiFiPassword"; // Replace with your WiFi pwd

// NTP server settings
const char* ntpServer = "pool.ntp.org"; // NTP server
const long gmtOffset_sec = 19800;        // GMT offset for Indian Standard Time (IST) in seconds
const int daylightOffset_sec = 0;        // No daylight saving time in India

// Initialize the matrix for a single 8x24 panel
Adafruit_NeoMatrix matrix = Adafruit_NeoMatrix(MATRIX_WIDTH, MATRIX_HEIGHT, DATA_PIN,
  NEO_MATRIX_TOP     + NEO_MATRIX_RIGHT +  // Orientation adjustments
  NEO_MATRIX_COLUMNS + NEO_MATRIX_PROGRESSIVE,
  NEO_GRB + NEO_KHZ800);

// Variables for time
struct tm timeinfo;

void setup() {
  // Start Serial Monitor for debugging
  Serial.begin(115200);
  
  // Initialize LED matrix
  matrix.begin();
  matrix.setTextWrap(false);              
  matrix.setBrightness(40);               
  matrix.setTextColor(matrix.Color(0, 0, 255)); // Set text color to blue

  // Connect to Wi-Fi
  Serial.print("Connecting to WiFi...");
  WiFi.begin(ssid, password);              // Connect to Wi-Fi
  while (WiFi.status() != WL_CONNECTED) { // Wait for connection
    delay(500);
    Serial.print(".");
  }
  Serial.println(" Connected!");
  
  // Initialize NTP
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
}

void loop() {
  // Get the current time
  if (!getLocalTime(&timeinfo)) {
    Serial.println("Failed to obtain time");
    delay(1000);
    return;
  }

  // Format time as HHMM
  char hourString[3];
  char minString[3];
  snprintf(hourString, sizeof(hourString), "%02d", timeinfo.tm_hour);
  snprintf(minString, sizeof(minString), "%02d", timeinfo.tm_min);

  // Clear the display
  matrix.fillScreen(0);  // Clear the screen

  // Combine hour and minute without separator
  String timeString = String(hourString) + String(minString);
  
  // Set cursor position (adjust as necessary)
  matrix.setCursor(0, (MATRIX_HEIGHT - 8) / 2); // Center vertically
  matrix.print(timeString);  // Print the time

  // Flashing effect on the 12th pixel (two pixels vertically)
  static bool flash = false;  // Track the flash state
  if (flash) {
    // Draw two vertically aligned pixels
    matrix.drawPixel(11, 2, matrix.Color(255, 0, 0)); // Top pixel (one pixel up)
    matrix.drawPixel(11, 4, matrix.Color(255, 0, 0)); // Bottom pixel (original position)
  } else {
    // Turn off the pixels
    matrix.drawPixel(11, 2, matrix.Color(0, 0, 0));   // Turn off top pixel
    matrix.drawPixel(11, 4, matrix.Color(0, 0, 0));   // Turn off bottom pixel
  }
  
  // Refresh the display
  matrix.show();  

  // Toggle flash state
  flash = !flash;

  delay(500);  // Update every half second for flashing effect
}

Usage:

• Upload the code to your ESP8266 using the Arduino IDE.
• Ensure your Wi-Fi credentials are correctly set.
• After connecting to Wi-Fi, the current time will be displayed, and the flashing effect will be visible.

Here’s a list of GMT offsets for different countries. Replace gmtOffset_sec with the desired offset value in seconds:

const long gmtOffset_sec = <value>;  // GMT offset in seconds for the chosen time zone

GMT Offsets for Various Countries

Country	Time Zone	Offset in Hours	Offset in Seconds
United Kingdom	GMT / UTC	0	0
United States (EST)	GMT-5	-5	-18000
United States (PST)	GMT-8	-8	-28800
India	GMT+5:30	5.5	19800
Japan	GMT+9	9	32400
China	GMT+8	8	28800
Australia (AEST)	GMT+10	10	36000
Russia (Moscow)	GMT+3	3	10800
Brazil (BRT)	GMT-3	-3	-10800
Germany	GMT+1	1	3600
France	GMT+1	1	3600
South Africa	GMT+2	2	7200
New Zealand	GMT+12	12	43200
Argentina	GMT-3	-3	-10800
Mexico (CST)	GMT-6	-6	-21600
UAE	GMT+4	4	14400
Saudi Arabia	GMT+3	3	10800
Turkey	GMT+3	3	10800
South Korea	GMT+9	9	32400
Pakistan	GMT+5	5	18000
Egypt	GMT+2	2	7200
Thailand	GMT+7	7	25200
Indonesia (Jakarta)	GMT+7	7	25200
Canada (CST)	GMT-6	-6	-21600
Italy	GMT+1	1	3600
Philippines	GMT+8	8	28800
Singapore	GMT+8	8	28800

You can use these values to set the gmtOffset_sec in your code based on the target country’s time zone. Remember to add or subtract based on whether the time zone is ahead or behind GMT.