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.
Components Required
- Arduino Uno
- SD Card Module
- DHT22 Temperature and Humidity Sensor
- SD Card (Higher than 8GB)
- Breadboard
- Connecting wires
Explanation
First of all, we will connect the SD Card module to the Arduino. Arduino can do read write operations on SD Card via SPI protocol. So we need to connect the SD card module to SPI pins of Arduino, which are pins 13, 12, 11 and 10. Since it is using SPI protocol, it won’t work if we connect SD card module to normal digital IO pins.
- SD Card Module Ground to Arduino Ground
- VCC of the module to 5V output of Arduino
- MISO of module to pin 12 of Arduino
- MOSI of module to pin 11 of Arduino
- SCK of module to pin 13 of Arduino
- CS of module to pin 10 of Arduino
Then we can connect the DHT22 to the Arduino.
- Connect VCC of DHT22 to 5V output of Arduino
- Ground to ground of Arduino
- Data pin of DHT22 to pin 8 of Arduino
DHT22 Library
You need to manually add DHT library to Arduino IDE as it is not included by default. You can ignore it if you already added it. Otherwise you can do following steps for that.
- Download DHT Library from here : DHT Sensor Library.
- Open Arduino IDE.
- Go to Sketch >> Include Library >> Add .ZIP Library
- Select the downloaded ZIP file and press open.
Read more: Temperature and Humidity Data Logger using Arduino