#include <DHT.h>              // Include DHT library code

#define DHTPIN  2             // DHT22 data pin is connected to Arduino pin 2
int led = 13;


#define DHTTYPE DHT22         // DHT22 sensor is used
DHT dht(DHTPIN, DHTTYPE);     // Initialize DHT library

void setup() {
  pinMode(led, OUTPUT);
  Serial.begin(9600);         // Initialize serial communications with the PC
 
  dht.begin();                // Initialize the DHT library
 
  Serial.println("CLEARDATA");       // Clear all Excel sheet data
  // Label columns: A for date, B for time, C for temperature and D for humidity
  Serial.println("LABEL,Date,Time,Temperature,Humidity");
}

void loop() {
  digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(5000);               // wait for a 5 second
  Serial.print("DATA,DATE,TIME,");       // Write date and time on row A and row B respectively
  Serial.print(dht.readTemperature());   // Read temperature from sensor and send its value to Excel
  Serial.print(",");                     // Move to next column
  Serial.print(dht.readHumidity());      // Read humidity from sensor and send its value to Excel
  Serial.println(",");                   // Move to next column and start new row
  digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW

  delay(900000);                           // Wait 15 minute
}