how can i create txt file from the date of RTC DS3231

Projects Programming
1

hello all,

i want to create txt files like "01032018.txt" automatically from the date of RTC DS3231 and save using sd card module.
i try this program but it can't, in this program i use sht 11 sensor to monitor temp and humidity.

#include <SD.h>
#include <SPI.h>
#include <DS3231.h>
#include <SHT1x.h>
#define dataPin  6   //pin 10 arduino to pin 1 SHT11
#define clockPin 7   // pin 11 arduino to pin 3 clock SHT11
SHT1x sht1x(dataPin, clockPin);
DS3231 rtc(SDA,SCL);

int suhu; 
int kelembaban; 
File myFile;
int pinCS = 10; // Pin 10 on Arduino Uno

void setup() {
  rtc.begin();
  Serial.begin(9600);
  pinMode(pinCS, OUTPUT);
  
  // SD Card Initialization
  if (SD.begin())
  {
    Serial.println("SD card is ready to use.");
  } else
  {
    Serial.println("SD card initialization failed");
    return;
  }
  rtc.begin();    
}

void loop() {
suhu = sht1x.readTemperatureC(); 
kelembaban = sht1x.readHumidity(); 

Serial.print(rtc.getDOWStr());
Serial.print(",");

Serial.print(rtc.getDateStr());
Serial.print(",");

//Read time
Serial.print(rtc.getTimeStr());
Serial.print(",");
Serial.print(suhu);
Serial.print(",");
Serial.println(kelembaban);

String filename=String(rtc.getDateStr() + ".txt");
char str[16] = {0};
filename.toCharArray(str,16);
myFile = SD.open(str, FILE_WRITE);
  
if (myFile) {    
myFile.print(rtc.getDOWStr());
myFile.print(",");

myFile.print(rtc.getDateStr());
myFile.print(",");

//Read time
myFile.print(rtc.getTimeStr());
myFile.print(",");

myFile.print(suhu);
myFile.print(",");
myFile.println(kelembaban);

    myFile.close(); // close the file
  }
  // if the file didn't open, print an error:
  else {
    Serial.println("error opening test.txt");
  }
  delay(3000);
}

thank you for your help :slight_smile:

2

i try this program but it can't

It can't what? Can't tie your shoes?

What IS in str when that code executes?

3

omg sorry. the error is "invalid operands of types 'char*' and 'const char [5]' to binary 'operator+'"

4

anindyadwi:
omg sorry. the error is "invalid operands of types 'char*' and 'const char [5]' to binary 'operator+'"

That is only part of the error message. The rest includes the file name and the line number where that is happening.

String filename=String(rtc.getDateStr() + ".txt");

Apparently, rtc.getDateStr() returns a char * - a pointer to a char array. You are then trying to increment that pointer by ".txt", which makes no sense at all.

If you insist on pissing away memory using Strings,

String filename = rtc.getDateStr();
filename += ".txt";