temperature and humidity supervision System

temperature and humidity supervision System

in this project temperature and humidity supervision ,this system  is based on arduino as controller and DHT22 sensor interfaced with labview . 

first i will begin with the arduino part :
to begin with lets connect  the  sensor to the arduino like in the picture below

• pin 1  to VCC (red wire)
• pin 2  Data pin with pin 2 inthe arduino (yellow wire )
• pin 3 not used 
• pin 4 to GND (black wire )

                             

now the arduino code :

                   #include <dht.h>  // import library

                   dht DHT;

                   #define DHT22_PIN 2 // data pin of the DHT22 sensor connected to pin 2

                   void setup()

                   {

                    Serial.begin(9600);  // prepare serial communication 

                    }

                   void loop()

                  {

                  int chk = DHT.read22(DHT22_PIN);  // read value from the sensor

                  float hu =DHT.humidity;                     // get humidity

                  float te =DHT.temperature;                // get temperture

                        if(Serial.available() > 0) {              // if there is data in serial port

                              if(Serial.read() =='t') {            // if the data == 't'

                                     Serial.println(te);             // print temperture

                               }

                               else if(Serial.read() == 'm') { // if data == 'm'

                                     Serial.println(hu);            // print humidity

                               }

                       }

                  }

now to the labview part
i m going to devide it to two sections :

• serial communication

the picture below present how the communication with the arduino is done ,the main idea is to read the temperature and humidity one at a time so after preparing the serial communication i send to the arduino the letter 't' so that the arduino will return the value of the temperature

and the same for the humidity after sending the letter 'm' to the arduino it will send back the value of the humidity . and the role of the while loop is just to let enough time to receive the value from the arduino






the basics of serial communication :

the first step is to open the serial port using VISA SERIAL

to write data to the serial port we use this bloc




to read data from serial we  use this bloc

• plotting and saving Data 

in this part the goal is to save Data in the text file and make it look simple and easy to read
so we use the concatinate bloc ,this bloc is used to concatinate strings

concatinat block

the basics of saving data in text file are :

to open or create a file using this bloc







to write in the txt file use this one






and at the end to close the file                                                                   




in the picture below you can find the hole diagramme of the second part







an this is the result

data saved in the text file