Temperature and Humidity Data Logger using Arduino

In this project, we are going to make a temperature and relative humidity data logger. Arduino is the brain of this project. DHT22 sensor is used for sensing temperature and relative humidity. Arduino Uno is programmed to read temperature, humidity values from DHT22 sensor and save it to a file in an SD Card. So whenever required we can take the SD Card for viewing data. Here we will take data from SD card and import it to excel to plot graphs.First of all, we have added libraries required for this project. Then we defined the DHT sensor type and pin to which it is connected.In the setup function, we initialized the serial communication at 9600 baudrate. Here serial communication is used only for displaying logs in the Arduino Serial Monitor. The dht.begin() function will initialize the Arduino for reading data from DHT sensor. Similarly sd.begin() function will initialize the Arduino for write data to SD card module. After that we will open the file “data.txt” from SD card using sd.open() function. Then we will write titles ‘Time’, ‘Humidity’, ‘Temperature_C’, ‘Temperature_F’ and ‘Heat_index’ in it. After that we will close the connection to save the file.