I created a function that saves the timestamp in a text file, but it saves unreadable. Full of invalid characters, example: Ÿ@ O ƒº!¥ Ÿ@ O ƒº!¥ Ÿ@ O ƒº!¥ Ÿ
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include "RTClib.h"
RTC_Millis rtc;
File txt;
const char * getCurrentTimestamp()
{
char dateBuffer[40];
DateTime now = rtc.now();
sprintf(dateBuffer,"%02u-%02u-%04u %02u:%02u:%02u", now.day(), now.month(), now.year(), now.hour(), now.minute(), now.second());
return dateBuffer;
}
void saveLog()
{
txt = SD.open("dados.txt", FILE_WRITE);
txt.print(getCurrentTimestamp());
txt.close();
}
void setup() {
pinMode(53, OUTPUT);
SD.begin(4);
Serial.begin(9600);
rtc.begin(DateTime(F(__DATE__), F(__TIME__)));
}
void loop() {
Serial.println(getCurrentTimestamp());
saveLog();
delay(1000);
}
My code is very simple, do not understand where I went wrong. if I copy the following code snippet for saveData() function and save the dateBuffer variable, everything works normally.
char dateBuffer[40];
DateTime now = rtc.now();
sprintf(dateBuffer,"%02u-%02u-%04u %02u:%02u:%02u", now.day(), now.month(), now.year(), now.hour(), now.minute(), now.second());
how to save the timestamp correctly in the file through the function getCurrentTimestamp() ?
