Hi all,
I'm a beginner in this and I'm trying to save data from a pH meter in a .txt file on a SD card.
I've got a Arduino nano, a pH meter v1.1 and a SD module.
I've tried to assemble some codes, but I am a very beginner and do not understand everything (i'm trying 
and learning at the same time also).
So I would be very greatful if someone can help me with my code.
I think the problem is coming from the RTClib since the programm stops whenever I try to use a funciton from this library (either "rtc.adjust(DateTime(DATE, TIME));" or " DateTime now = rtc.now();").
Do you know where it can come from?
Here is the code I'm using (sorry, i've tried to clean it but this is a mess):
// include the SD library:
#include <SD.h>
#include <RTClib.h>
RTC_DS1307 rtc;
// set up variables using the SD utility library functions:
Sd2Card card;
SdVolume volume;
SdFile root;
File myFile;
const int chipSelect = 4;
#define SensorPin 0 //pH meter Analog output to Arduino Analog Input 0
unsigned long int avgValue; //Store the average value of the sensor feedback
float b;
int buf[10],temp;
void setup()
{
// Open serial communications and wait for port to open:
Serial.begin(9600);
while (!Serial) {
; // wait for serial port to connect. Needed for Leonardo only
}
Serial.print("\nInitializing SD card...");
pinMode(10, OUTPUT);
if (!card.init(SPI_HALF_SPEED, chipSelect)) {
Serial.println("initialization failed. Things to check:");
Serial.println("* is a card is inserted?");
Serial.println("* Is your wiring correct?");
Serial.println("* did you change the chipSelect pin to match your shield or module?");
return;
} else {
Serial.println("Wiring is correct and a card is present.");
}
pinMode(13,OUTPUT);
Serial.begin(9600);
Serial.println("Ready"); //Test the serial monitor
// rtc.adjust(DateTime(__DATE__, __TIME__));
Serial.println("Ready2"); //Test the serial monitor
}
void loop(void) {
for(int i=0;i<10;i++) //Get 10 sample value from the sensor for smooth the value
{
buf[i]=analogRead(SensorPin);
delay(10);
}
for(int i=0;i<9;i++) //sort the analog from small to large
{
for(int j=i+1;j<10;j++)
{
if(buf[i]>buf[j])
{
temp=buf[i];
buf[i]=buf[j];
buf[j]=temp;
}
}
}
avgValue=0;
for(int i=2;i<8;i++) //take the average value of 6 center sample
avgValue+=buf[i];
float phValue=(float)avgValue*5.0/1024/6; //convert the analog into millivolt
phValue=3.5*phValue; //convert the millivolt into pH value
Serial.print(" pH:");
Serial.print(phValue,2);
Serial.println(" ");
digitalWrite(13, HIGH);
delay(800);
digitalWrite(13, LOW);
myFile = SD.open("data.txt", FILE_WRITE);
DateTime now = rtc.now();
myFile.print(now.year(), DEC);
myFile.print("/");
myFile.print(now.month(), DEC);
myFile.print("/");
myFile.print(now.day(), DEC);
myFile.print(" ");
myFile.print(now.hour(), DEC);
myFile.print(":");
myFile.print(now.minute(), DEC);
myFile.print(":");
myFile.print(now.second(), DEC);
myFile.print(", ");
myFile.print(phValue);
myFile.println(", ");
}