Datasheet

The first important thing is the delay() call, this is what makes the Arduino wait around until

its time to take another reading. If you recall we #defined the delay between readings to

be 1000 millseconds (1 second). By having more delay between readings we can use less

power and not fill the card as fast. Its basically a tradeoff how often you want to read data

but for basic long term logging, taking data every second or so will result in plenty of data!

Then we turn the green LED on, this is useful to tell us that yes we're reading/writing data

now.

Next we call millis() to get the 'time since arduino turned on' and log that to the card. It can

be handy to have - especially if you end up not using the RTC.

Serial.print(", ");

#endif

// fetch the time

now = RTC.now();

// log time

logfile.print(now.get()); // seconds since 2000

logfile.print(", ");

logfile.print(now.year(), DEC);

logfile.print("/");

logfile.print(now.month(), DEC);

logfile.print("/");

logfile.print(now.day(), DEC);

logfile.print(" ");

logfile.print(now.hour(), DEC);

logfile.print(":");

logfile.print(now.minute(), DEC);

logfile.print(":");

logfile.print(now.second(), DEC);

#if ECHO_TO_SERIAL

Serial.print(now.get()); // seconds since 2000

Serial.print(", ");

Serial.print(now.year(), DEC);

Serial.print("/");

Serial.print(now.month(), DEC);

Serial.print("/");

Serial.print(now.day(), DEC);

Serial.print(" ");

Serial.print(now.hour(), DEC);

Serial.print(":");

Serial.print(now.minute(), DEC);

Serial.print(":");

Serial.print(now.second(), DEC);

#endif //ECHO_TO_SERIAL