Problem with RTC countdown programming

Projects Programming
1

Hi, I want to make an UV exposure device controlled by an Arduino, but I can't make the countdown, I tried this code:

DateTime now = rtc.now();
  DateTime endtime;
  DateTime left;

  if(settime == false){
  endtime = now.unixtime() + MinuteIns * 60 + SecondsIns;
  settime = true;
  }
  
  left = endtime.unixtime() - now.unixtime();


    Serial.print(left.year(), DEC);
    Serial.print('/');
    Serial.print(left.month(), DEC);
    Serial.print('/');
    Serial.print(left.day(), DEC);
    Serial.print(' ');
    Serial.print(left.hour(), DEC);
    Serial.print(':');
    Serial.print(left.minute(), DEC);
    Serial.print(':');
    Serial.print(left.second(), DEC);
    Serial.println();
  delay(1000);
  }

This is a part of all the code but is here where it fails. If i put 10 in the SecondsIns variable and 0 in MinuteIns, in the serial monitor It shows me this:

2106/2/6 6:28:26
2060/2/8 5:46:40
2060/2/8 5:46:39
2060/2/8 5:46:38
2060/2/8 5:46:37
2060/2/8 5:46:36
2060/2/8 5:46:35

What do you think? Am I doing something wrong?

2

For starters, using calendar years, months and days to express a time difference? What time library are you using?

3

I tried this code

Among other code that we need to see.

 left = endtime.unixtime() - now.unixtime();

So, the value assigned to left is a value in seconds. It is a NOT a DateTime value.

4

aarg:
For starters, using calendar years, months and days to express a time difference? What time library are you using?

I'm Using RTClib.h as library

5

PaulS:
Among other code that we need to see.

 left = endtime.unixtime() - now.unixtime();

So, the value assigned to left is a value in seconds. It is a NOT a DateTime value.

I put this instead of all the other Serial.print lines

Serial.println(left.unixtime(),DEC);

and it happens the same, the serial monitor show me this, the first value is correct because the time is in seconds but the next iteration is surprisingly wrong :confused:

10
2843443416
2843443415
2843443414
2843443413
6

The value is not a DateTime value, so it makes no sense to assign it to a variable of type DateTime. The value is a number of seconds, so assign it to a variable of type int or long, depending on the magnitude of the value.

Do NOT expect to get valid data from left when the value assigned to it is garbage.

7

MrWilliam932:
I'm Using RTClib.h as library

Look at dateCalc.ino for ideas.

8

@MrWilliam932:

Please post your entire sketch.

9

odometer:
@MrWilliam932:

Please post your entire sketch.

This is all the code (some variables are in spanish), this time the left.unixtime() tells me the correct time in seconds but i can't show it in minutes and seconds, I think its easy to resolve the code having the time in seconds.

#include <Keypad.h>
#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
#include "RTClib.h"
RTC_Millis rtc;
LiquidCrystal_I2C lcd(0x27,16,2);
const byte ROWS = 4;
const byte COLS = 3;
char keys[ROWS][COLS] = {
  {'1','2','3'},
  {'4','5','6'},
  {'7','8','9'},
  {'*','0','#'}
};
byte rowPins[ROWS] = {2, 3, 4, 5};
byte colPins[COLS] = {6, 7, 8}; 
 
Keypad keypad = Keypad( makeKeymap(keys), rowPins, colPins, ROWS, COLS );
String Tiempo = "00:00";
String Minutos ="00";
String Segundos ="00";
boolean Insolando = false;
byte menupos = 0;
byte TiempoCursor = 0;
byte MinutosIns = 0;
byte SegundosIns = 0;
byte Capas = 0;
char key;
boolean waitforconf = true;
boolean settime = false;
unsigned long endtime;

void setup() {
  Serial.begin(9600);
  Wire.begin();
  lcd.init();
  lcd.backlight();
rtc.begin(DateTime(F(__DATE__), F(__TIME__)));
  
  
  
  lcd.print("Bienvenido");
  delay(2000);
  lcd.clear();
}

void loop() {
  switch(Insolando){
  case false:
  //Programa de configuración
  while(Insolando == false){
    delay(200);
    switch(menupos){
      case 0:
    lcd.setCursor(0,0);  
    lcd.print("Tiempo de Insol.");
    lcd.setCursor(0,1);
    lcd.print(Tiempo);
    key = keypad.getKey();
    if (key){
   TiempoCursor = constrain(TiempoCursor,0,4);
   if(TiempoCursor== 2){
     TiempoCursor = 3;
     }
     if(key == '*'){ 
       Minutos = Tiempo.substring(0,2);
       MinutosIns = Minutos.toInt();
       Segundos = Tiempo.substring(3);
       SegundosIns = Segundos.toInt();
         if(SegundosIns >= 60 || MinutosIns >= 60 || SegundosIns == 0 && MinutosIns == 0){
           
           lcd.setCursor(0,0);
           lcd.clear();
           lcd.print("Valor Incorrecto");
           delay(1000);
           
           Tiempo = "00:00";  
           TiempoCursor = 0;
           menupos = 0;
           lcd.clear();
           break;
         }
       TiempoCursor = 0;
       menupos = 1;
       lcd.clear();
       break;
       }
       else if(key == '#'){
       Tiempo = "00:00";  
       TiempoCursor = 0;
       menupos = 0;
       lcd.clear();
       break;
       }
   Tiempo.setCharAt(TiempoCursor, key);
     TiempoCursor++; 
    }
      break;
    case 1:
      lcd.setCursor(0,0);
      lcd.print("Cara:1->Inf.");
      lcd.setCursor(0,1);
      lcd.print("2->Sup 3->Ambas");
      key = keypad.getKey();
      if (key){
        
        lcd.clear();
        if(key == '1'){
          Capas = 1;
          menupos = 2;
          }
         else if(key == '2'){
          Capas = 2;
          menupos = 2;
          }
          else if(key == '3'){
          Capas = 3;
          menupos = 2;
          }
          else if(key == '#'){
          
          menupos = 0;
          
          }
          else{
            lcd.clear();
            lcd.setCursor(0,0);
            lcd.print("Selecciona un");
          lcd.setCursor(0,1);
            lcd.print("valor correcto");
          delay(2000);
          lcd.clear();
          
         menupos=1;
         Capas = 0;
          
            }
        }
    break;
  case 2:
    lcd.setCursor(0,0);
    lcd.print(MinutosIns);
    lcd.print(" Mins y ");
    lcd.print(SegundosIns);
    lcd.print(" Segs");
    lcd.setCursor(0,1);
    if(Capas == 1){
      lcd.print("Capa Inferior");
      }
      else if (Capas == 2){
        lcd.print("Capa Superior");
        }
        else if (Capas == 3){
        lcd.print("Doble Capa");
        }
        delay(2500);
        lcd.clear();
        waitforconf = true;
        while(waitforconf == true){
        
        lcd.setCursor(0,0);
        lcd.print("ACEPTAR?");
        lcd.setCursor(0,1);
        lcd.print("*->Si #->Atras");
        
        
        key = keypad.getKey();
      if (key){
        lcd.clear();
        if(key == '*'){
          waitforconf = false;
          Insolando = true;
          break;
          }
         else if(key == '#'){
          waitforconf = false;
          menupos = 1;
          }
        }
        }
  break;  
      
  }
    }
    break;
    lcd.clear();
  case true:
  while(Insolando == true){

DateTime now = rtc.now();


  
if(settime == false){
  endtime = now.unixtime() + MinutosIns * 60 + SegundosIns;
  settime = true;
  }
  
  DateTime left = endtime - now.unixtime();
  Serial.println(left.unixtime(),DEC);
  Serial.println(endtime);
  Serial.println(now.unixtime());
  
  
  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print(left.minute());
  lcd.print(':');
  lcd.print(left.second());
//  lcd.print("Insolando...");
//  lcd.setCursor(0,1);
//  lcd.print(left.minute());
//  lcd.print(':');
//  lcd.print(left.second());

//if(left.unixtime() == 0){
//  settime = false;
//  Tiempo = "00:00";
//  Minutos ="00";
//Segundos ="00";
//Insolando = false;
//menupos = 0;
//TiempoCursor = 0;
//MinutosIns = 0;
//SegundosIns = 0;
//Capas = 0;
//waitforconf = true;
//break;
//  }
  delay(1000);
  break;
  }
  
}
}