TTGO Internet Watch

This is a TTGO T1 board which is an ESP32 powered Dev board which have an ST7789V 1.14 Inch Display.

Here's a cool project for this Board, an "Internet Clock".

I always wanted to make a Clock project as it requires quite a few stuff jam-packed in a small compact form factor.

like for example, to run a clock we need a LiPo cell and to charge that cell we need a charging circuit of some sort on it. the clock also needs a deep sleep mode which will save the battery from constant discharge.

The charging circuit has an overcharge and over-discharge feature which will protect the battery from these two issues, one IC which can be used here is the TP4056 which is ideal for such a task.

BUT the TTGO T1 already has a battery management IC so we don't really need to make any complex circuitry of any sort, also we don't need to add an external display to this board as it already has quite a powerful display onboard.

Also, no PCB is needed for this setup.

even for the Body of the Clock, I will be making a custom enclosure that will have slots for a Wrist strap.

Anyways, let's get started with the main part for this small built which is - editing the ESP32 Clock example sketch.

But even before that, these are the things do you need for this small built_

• TTGO T display Board
• Stable Wifi connection
• And Your country's UTC. (find your country's UTC from here)

Before starting this project, you require ESP32 Boards core installed on Arduino IDE which is a necessity. Install them from here-https://github.com/espressif/arduino-esp32

• So first, open SimpleTime sketch which can be found in Example>ESP32>Time>SimpleTime

this is the generic internet clock sketch that we will use as a base sketch.

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

const char* ssid       = "YOUR_SSID";
const char* password   = "YOUR_PASS";

const char* ntpServer = "pool.ntp.org";
const long  gmtOffset_sec = 3600;
const int   daylightOffset_sec = 3600;

void printLocalTime()
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    Serial.println("Failed to obtain time");
    return;
  }
  Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S");
}

void setup()
{
  Serial.begin(115200);
  
  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
  }
  Serial.println(" CONNECTED");
  
  //init and get the time
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  printLocalTime();

  //disconnect WiFi as it's no longer needed
  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
}

void loop()
{
  delay(1000);
  printLocalTime();
}

Our goal here is to Display the time which is in the serial monitor on TTGO's Display and for that, we have to change a few lines of code in this sketch.

• We first add our SSID and Password in this sketch.

const char* ssid       = "YOUR_SSID";
const char* password   = "YOUR_PASS";

• Now we have to add gmtOffset_sec which can be found from here. for example, I live in India and GMT here is +5:30.
• +5:30 in seconds is 19800s so we add 19800 in the GMT offset

const long  gmtOffset_sec = 19800;

Next is the daylightOffset_set, if your country has daylight saving time then set it according to that time in seconds, and if not then set it to zero.

const int   daylightOffset_sec = 0;

Find out about the daylight saving time from here.

This will be the final sketch (not exactly final, this is just for serial printing the time)

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

const char* ssid       = "xxxxxx";
const char* password   = "pppppp";

const char* ntpServer = "pool.ntp.org";
const long  gmtOffset_sec = 19800;
const int   daylightOffset_sec = 0;

void printLocalTime()
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    Serial.println("Failed to obtain time");
    return;
  }
  Serial.println(&timeinfo, "%A, %B %d %Y %H:%M:%S");
}

void setup()
{
  Serial.begin(115200);
  
  //connect to WiFi
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
  }
  Serial.println(" CONNECTED");
  
  //init and get the time
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  printLocalTime();

  //disconnect WiFi as it's no longer needed
  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
}

void loop()
{
  delay(1000);
  printLocalTime();
}

• Plug your TTGO board
• Select the right board in the Board manager
• select the right port
• hit upload
• Now open the serial monitor and you will see the current time printing repetitive at an interval of 1 second.

If your time is not correct then this might be because of an error in UTC offset and daylight saving offset.

Now, this was the basic Internet time sketch, for displaying this on the TTGO T1 board, we only have to use a simple function that lets us display anything on TTGO's display.

But before that, you need to install this library which is a TFT Display library that we require for this task.

We first add the TFT_eSPI library and other important lines of code which is required to print anything on the display.

Here's the main sketch

#include <TFT_eSPI.h> // Graphics and font library for ST7735 driver chip
#include <SPI.h>
#include <WiFi.h>
#include "time.h"

const char* ssid       = "xxxxxx"; //add your WIFI Credentials
const char* password   = "pppppp";

const char* ntpServer = "pool.ntp.org";
const long  gmtOffset_sec = 19800;    //UTC Offset!
const int   daylightOffset_sec = 0;



TFT_eSPI tft = TFT_eSPI();  // Invoke library, pins defined in User_Setup.h

#define TFT_BLACK 0x0000 // black

void setup(void) {
  tft.init();
  tft.setRotation(1);
  
  Serial.begin(115200);
  
  Serial.printf("Connecting to %s ", ssid);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
  }
  Serial.println(" CONNECTED");
  
  configTime(gmtOffset_sec, daylightOffset_sec, ntpServer);
  printLocalTime();

  WiFi.disconnect(true);
  WiFi.mode(WIFI_OFF);
 
}

void loop() {

delay(1000);
printLocalTime();
}


void printLocalTime()
{
  struct tm timeinfo;
  if(!getLocalTime(&timeinfo)){
    Serial.println("Failed to obtain time");
    return;
  }
  
  tft.fillScreen(TFT_BLACK);
  tft.setCursor(0, 0, 2);
  tft.setTextColor(TFT_WHITE,TFT_BLACK);  
  tft.setTextSize(1);
  tft.println(&timeinfo, "%A");

  tft.setCursor(0, 20, 2);
  tft.setTextColor(TFT_WHITE,TFT_BLACK);  
  tft.setTextSize(1);
  tft.println(&timeinfo, "%B %d %Y");

  tft.setCursor(0, 40, 2);
  tft.setTextColor(TFT_WHITE,TFT_BLACK);  
  tft.setTextSize(1);
  tft.println(&timeinfo,"%H:%M:%S");

}

Upload this sketch to your TTGO Board and This will be the result-

As for the battery, I used a 3.7V 500mA Lipo cell which I have salvaged from an old project.

Also, we can change the size of the font by changing this line of code from 1 to 2.

tft.setTextColor(TFT_WHITE,TFT_BLACK);  
  tft.setTextSize(1); //Change it to 2
  tft.println(&timeinfo, "%A");

I have to change the connecting wire of the LiPo cell to a smaller connector wire which was included with the TTGO T1 board.

This was the basic setup for this watch project.

Next is to design a Body for this setup. For that, I will be using Fusion360.

Custom Body Concept

I designed this Body for the TTGO board which looks like an M5StickC board, the 3D Model for this TTGO Board was downloaded from grabcad user MIMOSA

For now, I haven't decided on the wrist strap for this project, I will probably buy the generic leather strap for this project as well.

This is all for part 2 though, the basic setup of this watch project is this, a TTGO T display board hooked up with a LiPo Cell which displays the current time and date on its DIsplay and this all is enclose nicely in a 3D Printed Body.

RESULT

stay tuned for part 2 of this watch project and ill be back!