Published January 16, 2017 © GPL3+

Countdown Calendars

Display the number of days until the next event from your Google hosted calendars.

BeginnerFull instructions provided1 hour3,410

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

Close enough to the one I used... Makerfocus 2pcs ESP8266 Module ESP-12E from Amazon

I2c OLED Module 128X64

Solderless Breadboard Half Size

Jumper wires (generic)

Software apps and online services

Google Apps Script - Calendars

Story

I got some gift card money and decided to try making something with ESP8266. While I was adding to my cart I saw a deal on OLED screens too. Once I got past "Hello World". This is what I came up with.

I first thought I was going to use something like IFTTT but soon realized I could go direct for what I wanted. The trick is to use Google Apps Script.

Google Apps Script

https://www.google.com/script/start/

Create the script for you calendar that you want to use. I created a new calendar named "Countdown". This is a separate calendar just for this device. I am not sure about the security, but I don't care who knows about my countdown calendar.

Once you save and confirm that it is working. You will need to publish it as a web app.

be sure to check the correct project version

If you want more calendars or the phases of the moon, repeat above. I only was interested in the new moon, so I filtered on that and only have the one graphic. It is up to you to expand the code if you want more phases to display.

moon graphic!

The ESP8266

The wiring is pretty simple, and so is the code. I am using the WiFi manger library to make it more portable. The WiFi manager allows you to move it from access point to access point without having to update your code.

Go ahead and modify how you see fit. I started with one calendar then added another and moved everything around.

Code

function doGet(e) {
  
  // name of you calendar
  var cal = CalendarApp.getCalendarsByName('Countdown')[0];

  if (cal === undefined) {
    return ContentService.createTextOutput('no access to calendar');
  }
 
  const now = new Date();
  var start = new Date(); start.setHours(0, 0, 0); // start at midnight
  const oneday = 24*3600000; // [msec]
  const stop = new Date(start.getTime() + 365 * oneday);
  
  var events = cal.getEvents(start, stop);
  var str = '';

    var event=events[0];
    var startDate=event.getStartTime();
  
  var daysTil = Math.ceil(((startDate - now) / oneday));

  //Logger.log(daysTil);

  str += event.getTitle() + '\t' + daysTil +'\n';

  return ContentService.createTextOutput(str);
}

function doGet(e) {
  
  var cal = CalendarApp.getCalendarsByName('Phases of the Moon')[0];

  if (cal === undefined) {
    return ContentService.createTextOutput('no access to calendar');
  }
 
  const now = new Date();
  var start = new Date(); start.setHours(0, 0, 0); // start at midnight
  const oneday = 24*3600000; // [msec]
  const stop = new Date(start.getTime() + 30 * oneday);
    
  var events = cal.getEvents(start, stop, {search: 'Full moon'});
  var str = '';

    var event=events[0];
    var startDate=event.getStartTime();
  
  var daysTil = Math.ceil(((startDate - now) / oneday));
  var moonStart = event.getTitle().slice(10);

  // Logger.log(daysTil);
  // Logger.log(moonStart);
  

  str += moonStart + '\t' + daysTil +'\n';

  return ContentService.createTextOutput(str);
}

#include <Arduino.h>
#include <U8g2lib.h>

#ifdef U8X8_HAVE_HW_SPI
#include <SPI.h>
#endif
#ifdef U8X8_HAVE_HW_I2C
#include <Wire.h>
#endif

U8G2_SSD1306_128X64_NONAME_1_SW_I2C u8g2(U8G2_R0, D2, D1, U8X8_PIN_NONE);   // All Boards without Reset of the Display


#include <ESP8266WiFi.h>          //https://github.com/esp8266/Arduino

//needed for library
#include <DNSServer.h>
#include <ESP8266WebServer.h>
#include <WiFiManager.h>          //https://github.com/tzapu/WiFiManager

#include "HTTPSRedirect.h"

//Connection Settings
const char* host = "script.google.com";
const char* googleRedirHost = "script.googleusercontent.com";
const int httpsPort = 443;

const String delimeter = "|";
String eventTitle = "";
String eventCount = "";
String eventTitle2 = "";
String eventCount2 = "";
String eventTime2 = "";

//


static const unsigned char fullmoon_xbm[] U8X8_PROGMEM = {
  0x00, 0x00, 0xFC, 0x0F, 0x00, 0x00, 0x00, 0x80, 0x83, 0x70, 0x00, 0x00, 
  0x00, 0x60, 0x81, 0xC0, 0x01, 0x00, 0x00, 0x98, 0x00, 0x21, 0x06, 0x00, 
  0x00, 0x46, 0x00, 0x00, 0x1C, 0x00, 0x00, 0x21, 0x50, 0x81, 0x26, 0x00, 
  0x80, 0x00, 0x48, 0x9B, 0x4F, 0x00, 0x40, 0x12, 0xA0, 0x00, 0xFF, 0x00, 
  0x20, 0x04, 0xE9, 0x2A, 0x86, 0x01, 0x10, 0x12, 0xF2, 0x11, 0x40, 0x02, 
  0x10, 0x08, 0xD2, 0xF7, 0xC2, 0x02, 0x88, 0x85, 0xE9, 0xFE, 0x79, 0x05, 
  0x88, 0x22, 0xC8, 0x77, 0xFA, 0x04, 0x84, 0x44, 0xFA, 0xFF, 0xFF, 0x08, 
  0xE4, 0x9B, 0x08, 0xFF, 0xFD, 0x08, 0xC6, 0x0D, 0x3C, 0x37, 0x74, 0x11, 
  0xA6, 0x0D, 0x80, 0x2E, 0x30, 0x15, 0xC2, 0xA3, 0x38, 0xFC, 0x00, 0x11, 
  0xE5, 0x09, 0x0A, 0xC8, 0x00, 0x29, 0xC9, 0x55, 0x33, 0x00, 0x40, 0x33, 
  0xB1, 0x8B, 0x02, 0x00, 0x08, 0x24, 0xEB, 0x17, 0x01, 0x00, 0x50, 0x20, 
  0x83, 0x46, 0x2B, 0x00, 0x00, 0x30, 0x6F, 0xA1, 0x51, 0x00, 0x00, 0x20, 
  0xF7, 0xC0, 0x06, 0x00, 0x10, 0x20, 0x8D, 0x10, 0x02, 0x00, 0x00, 0x20, 
  0xBF, 0x8A, 0x80, 0x00, 0x00, 0x30, 0x3F, 0x10, 0x16, 0x00, 0x00, 0x30, 
  0xBE, 0x48, 0x18, 0x00, 0x00, 0x10, 0xFE, 0x11, 0xDB, 0x00, 0x00, 0x10, 
  0x7E, 0x9A, 0x74, 0x00, 0x08, 0x10, 0xFC, 0xCF, 0x0F, 0x00, 0x00, 0x08, 
  0xEC, 0xBF, 0xFF, 0x00, 0x02, 0x08, 0xF8, 0xFF, 0xAF, 0x41, 0x00, 0x04, 
  0xE8, 0xBF, 0xE1, 0x00, 0x00, 0x04, 0xD0, 0xEF, 0xC1, 0x00, 0x04, 0x02, 
  0x90, 0x5B, 0x5D, 0x00, 0x00, 0x03, 0x60, 0x8F, 0x17, 0x02, 0x00, 0x01, 
  0x40, 0xE8, 0x77, 0x00, 0x80, 0x00, 0x80, 0x50, 0x77, 0x01, 0x40, 0x00, 
  0x00, 0x01, 0x05, 0x00, 0x20, 0x00, 0x00, 0x0E, 0x04, 0x04, 0x18, 0x00, 
  0x00, 0x18, 0x00, 0x08, 0x06, 0x00, 0x00, 0x60, 0x40, 0x80, 0x01, 0x00, 
  0x00, 0x80, 0x33, 0x72, 0x00, 0x00, 0x00, 0x00, 0xFC, 0x0F, 0x00, 0x00, 
  };





unsigned long previousMillis = 0;
const long interval = 3600000; 

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.flush();
  
  //WiFiManager
  //Local intialization. Once its business is done, there is no need to keep it around
  WiFiManager wifiManager;
  //reset settings - for testing
  //wifiManager.resetSettings();

  //sets timeout until configuration portal gets turned off
  //useful to make it all retry or go to sleep
  //in seconds
  wifiManager.setTimeout(180);
  
  //fetches ssid and pass and tries to connect
  //if it does not connect it starts an access point with the specified name
  //here  "AutoConnectAP"
  //and goes into a blocking loop awaiting configuration
  if(!wifiManager.autoConnect("AutoConnectAP")) {
    Serial.println("failed to connect and hit timeout");
    delay(3000);
    //reset and try again, or maybe put it to deep sleep
    ESP.reset();
    delay(5000);
  } 

  //if you get here you have connected to the WiFi
  Serial.println("connected... :)");
  u8g2.begin();
  // init calendars
  //replace with you gscript ids
  getCalendar1("BHfycWje68avEHz6n09mOPsMWTq_Y7JHuGBNIC320jAmm2aYiE");
  getCalendar2("MKfl1QedMs5004Z35Fer9HxgPDfuSHP8olhkJJ8yICn3H8H_Fn");

}


void loop() {

  u8g2.firstPage();
  do {
    calendar1();
  } while ( u8g2.nextPage() );
  delay(10000);
 
  u8g2.firstPage();
  do {  
    calendar2();    
  } while( u8g2.nextPage() ); 
 delay(10000); 

 // update calendar each hour
 unsigned long currentMillis = millis();
  if (currentMillis - previousMillis >= interval) {
    previousMillis = currentMillis;
      getCalendar1("BHfycWje68avEHz6n09mOPsMWTq_Y7JHuGBNIC320jAmm2aYiE");
      getCalendar2("MKfl1QedMs5004Z35Fer9HxgPDfuSHP8olhkJJ8yICn3H8H_Fn");
  }
}


//Get calendar entries from google

String fetchDataFromGoogle(String GScriptId) {
  String url = String("/macros/s/") + GScriptId + "/exec";
  HTTPSRedirect client(httpsPort);
  Serial.print("Connecting to ");
  Serial.println(host);

  if (!client.connected())
    client.connect(host, httpsPort);

  String data = client.getData(url, host, googleRedirHost);

// Serial.println(data);
return(data);
}

String getValue(String data, char separator, int index)
{
    int found = 0;
    int strIndex[] = { 0, -1 };
    int maxIndex = data.length() - 1;

    for (int i = 0; i <= maxIndex && found <= index; i++) {
        if (data.charAt(i) == separator || i == maxIndex) {
            found++;
            strIndex[0] = strIndex[1] + 1;
            strIndex[1] = (i == maxIndex) ? i+1 : i;
        }
    }
    return found > index ? data.substring(strIndex[0], strIndex[1]) : "";
}

void calendar1(){
      u8g2.setFont(u8g2_font_helvB08_tr);
u8g2.setCursor(0, 14);
u8g2.print(eventTitle);
if (eventCount == "today"){
   u8g2.setFont(u8g2_font_logisoso24_tr);
   u8g2.setCursor(20, 44);
}else{
   u8g2.setFont(u8g2_font_logisoso46_tr);
   u8g2.setCursor(0, 64);
}
u8g2.print(eventCount);
}

void getCalendar1(String GScriptId){
String data = fetchDataFromGoogle(GScriptId);
// Serial.println(data);
eventTitle = getValue(data, '\t', 0);
eventCount = getValue(data, '\t', 1);
if (eventCount.toInt()>0) {
 eventCount = String(eventCount + "d"); 
} else {
  eventCount = "today";
}

    Serial.println(eventTitle);
    Serial.println(eventCount);
  
}

void calendar2(){
      u8g2.setFont(u8g2_font_helvB08_tr);
      u8g2.setFontMode(1);
u8g2.setCursor(0, 14);
u8g2.print(eventTitle2);sub

if (eventCount2 == "today"){
   u8g2.setFont(u8g2_font_logisoso24_tr);
   u8g2.setCursor(20, 44);
}else{
   u8g2.setFont(u8g2_font_logisoso24_tr);
   u8g2.setCursor(54, 44);
}
   u8g2.print(eventCount2);
   u8g2.setFont(u8g2_font_logisoso16_tr);
   u8g2.setCursor(54, 64);
   u8g2.print("DAYS");
   u8g2.drawXBM(0, 18, 46, 46, fullmoon_xbm);
}

void getCalendar2(String GScriptId){

String data = fetchDataFromGoogle(GScriptId);
// Serial.println(data);
eventTime2 = getValue(data, '\t', 0);
eventCount2 = getValue(data, '\t', 1);
if (eventCount.toInt()>9) {
 eventCount2 = String("0" + eventCount2); 
}
eventTitle2 = "New Moon @ " + eventTime2;
    Serial.println(eventTitle2);
    Serial.println(eventCount2);
}

Credits

Brian Wente

5 projects • 8 followers

Countdown Calendars

Things used in this project

Hardware components

Software apps and online services

Story

Google Apps Script

The ESP8266

Schematics

Wiring

Code

getCalendarEvent.gs

getNewMoon.gs

GetCalendars

Credits

Brian Wente

Comments

Embed the widget on your own site

Countdown Calendars

Countdown Calendars

Things used in this project

Hardware components

Software apps and online services

Story

Google Apps Script

The ESP8266

Schematics

Wiring

Code

getCalendarEvent.gs

getNewMoon.gs

GetCalendars

Credits

Brian Wente

Comments

Related channels and tags