Arduino Temperature Data Logger with SD Card Module

/*
 * Gnd_To_Vcc 
 * 
 */

#include <SPI.h> //for the SD card module
#include <SD.h> // for the SD card
#include <DHT.h> // for the DHT sensor
#include <RTClib.h> // for the RTC

//define DHT pin
#define DHTPIN 2     // what pin we're connected to

// uncomment whatever type you're using
#define DHTTYPE DHT11   // DHT 11 
//#define DHTTYPE DHT22   // DHT 22  (AM2302)
//#define DHTTYPE DHT21   // DHT 21 (AM2301)

// initialize DHT sensor for normal 16mhz Arduino
DHT dht(DHTPIN, DHTTYPE);

// change this to match your SD shield or module;
// Arduino Ethernet shield and modules: pin 4
// Data loggin SD shields and modules: pin 10
// Sparkfun SD shield: pin 8
const int chipSelect = 4; 

// Create a file to store the data
File myFile;

// RTC
RTC_DS1307 rtc;

void setup() {
  //initializing the DHT sensor
  dht.begin();

  //initializing Serial monitor
  Serial.begin(9600);
  
  // setup for the RTC
  while(!Serial); // for Leonardo/Micro/Zero
    if(! rtc.begin()) {
      Serial.println("Couldn't find RTC");
      while (1);
    }
    else {
      // following line sets the RTC to the date & time this sketch was compiled
      rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
    }
    if(! rtc.isrunning()) {
      Serial.println("RTC is NOT running!");
    }
    
  // setup for the SD card
  Serial.print("Initializing SD card...");

  if(!SD.begin(chipSelect)) {
    Serial.println("initialization failed!");
    return;
  }
  Serial.println("initialization done.");
    
  //open file
  myFile=SD.open("DATA.txt", FILE_WRITE);

  // if the file opened ok, write to it:
  if (myFile) {
    Serial.println("File opened ok");
    // print the headings for our data
    myFile.println("Date,Time,Temperature ºC");
  }
  myFile.close();
}

void loggingTime() {
  DateTime now = rtc.now();
  myFile = SD.open("DATA.txt", FILE_WRITE);
  if (myFile) {
    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(",");
  }
  Serial.print(now.year(), DEC);
  Serial.print('/');
  Serial.print(now.month(), DEC);
  Serial.print('/');
  Serial.println(now.day(), DEC);
  Serial.print(now.hour(), DEC);
  Serial.print(':');
  Serial.print(now.minute(), DEC);
  Serial.print(':');
  Serial.println(now.second(), DEC);
  myFile.close();
  delay(1000);  
}

void loggingTemperature() {
  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  // Read temperature as Celsius
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit
  //float f = dht.readTemperature(true);
  
  // Check if any reads failed and exit early (to try again).
  if  (isnan(t) /*|| isnan(f)*/) {
    Serial.println("Failed to read from DHT sensor!");
    return;
  }
  
  //debugging purposes
  Serial.print("Temperature: "); 
  Serial.print(t);
  Serial.println(" *C");
  //Serial.print(f);
  //Serial.println(" *F\t"); 
  
  myFile = SD.open("DATA.txt", FILE_WRITE);
  if (myFile) {
    Serial.println("open with success");
    myFile.print(t);
    myFile.println(",");
  }
  myFile.close();
}

void loop() {
  loggingTime();
  loggingTemperature();
  delay(5000);
}