Get Epoch/Unix Time with the ESP8266 NodeMCU (Arduino)

This quick guide shows how to get epoch/unix time using the ESP826 NodeMCU board with Arduino IDE. Getting the epoch time can be useful to timestamp your readings, give unique names to files, and other applications. We’ll request the current epoch time from an NTP server, so the ESP8266 board needs to have an Internet connection.

If you want to get date and time in a human readable format, we recommend the following tutorial instead:

• ESP8266 NodeMCU NTP Client-Server: Get Date and Time (Arduino IDE)

What is epoch time?

The Epoch Time (also know as Unix epoch, Unix time, POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z).

NTP (Network Time Protocol)

NTP stands for Network Time Protocol and it is a networking protocol for clock synchronization between computer systems. In other words, it is used to synchronize computer clock times in a network.

There are NTP servers like pool.ntp.org that anyone can use to request time as a client. In this case, the ESP8266 is an NTP Client that requests time from an NTP Server (pool.ntp.org).

ESP8266 Get Epoch/Unix Time Function

To get epoch/unix time with the ESP8266, you can use the following function getTime():

// Function that gets current epoch time
unsigned long getTime() {
  timeClient.update();
  unsigned long now = timeClient.getEpochTime();
  return now;
}

This function returns the current epoch time. Continue reading for a complete example.

ESP8266 NodeMCU Get Epoch/Unix Time Example

Copy the following code to your Arduino IDE. This code connects to the internet and requests the time from an NTP server (pool.ntp.org).

/*
  Rui Santos
  Complete project details at https://RandomNerdTutorials.com/epoch-unix-time-esp8266-nodemcu-arduino/
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files.
  
  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.
*/

#include <ESP8266WiFi.h>
#include <NTPClient.h>
#include <WiFiUdp.h>

// Replace with your network credentials
const char* ssid = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";

// Define NTP Client to get time
WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org");

// Variable to save current epoch time
unsigned long epochTime; 

// Function that gets current epoch time
unsigned long getTime() {
  timeClient.update();
  unsigned long now = timeClient.getEpochTime();
  return now;
}

// Initialize WiFi
void initWiFi() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi ..");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print('.');
    delay(1000);
  }
  Serial.println(WiFi.localIP());
}

void setup() {
  Serial.begin(115200);
  initWiFi();
  timeClient.begin();
}

void loop() {
  epochTime = getTime();
  Serial.print("Epoch Time: ");
  Serial.println(epochTime);
  delay(1000);
}

View raw code

Insert your network credentials in the following variables and the code will work straight away:

// Replace with your network credentials
const char* ssid = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";

How the Code Works

Let’s take a quick look on how the code works.

Libraries

First, include the necessary libraries

#include <ESP8266WiFi.h>
#include <NTPClient.h>
#include <WiFiUdp.h>

Network Credentials

Insert your network credentials in the following variables so that the ESP8266 can connect to your network.

// Replace with your network credentials
const char* ssid = "REPLACE_WITH_YOUR_SSID";
const char* password = "REPLACE_WITH_YOUR_PASSWORD";

NTP Server

Define an NTP client to get time.

WiFiUDP ntpUDP;
NTPClient timeClient(ntpUDP, "pool.ntp.org");

We’ll request the time from pool.ntp.org, which is a cluster of time servers that anyone can use to request the time.

getTime() function

The getTime() function gets and returns the current epoch time.

// Function that gets current epoch time
unsigned long getTime() {
  timeClient.update();
  unsigned long now = timeClient.getEpochTime();
  return now;
}

initWiFi()

The initWiFi() function initializes Wi-Fi and connects the ESP8266 to your local network.

void initWiFi() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  Serial.print("Connecting to WiFi ..");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print('.');
    delay(1000);
  }
  Serial.println(WiFi.localIP());
}

setup()

In the setup(), initialize the Serial Monitor at a baud rate of 115200.

Serial.begin(115200);

Call the initWiFi() function to initialize Wi-Fi:

initWiFi();

Initialize the NTP client.

timeClient.begin();

loop()

In the loop(), get the epoch time and save it in the epochTime variable:

epochTime = getTime();

Finally, print the epoch time every second:

Serial.print("Epoch Time: ");
Serial.println(epochTime);
delay(1000);

Demonstration

Upload the code to your ESP8266 board. Then, open the Serial Monitor at a baud rate of 115200. It should connect to Wi-Fi and start printing the current epoch/unix time every second.

Wrapping Up

This was a quick guide showing you how to get epoch or also known as unix time with the ESP8266 NodeMCU. The epoch time is the number of seconds elapsed since January 1 1970. To get time, we need to connect to an NTP server, so the ESP8266 needs to have access to the internet.

If you’re interested in getting date and time in a human readable format, refer to the next tutorial:

• ESP8266 NodeMCU NTP Client-Server: Get Date and Time (Arduino IDE)

We hope you’ve found this tutorial useful. If you want to learn more about the ESP8266, check our resources:

• Home Automation using ESP8266
• Build Web Servers with ESP32 and ESP8266
• More ESP8266 NodeMCU Projects and Guides…

Thanks for reading.