Getting Started with Raspberry Pi, DHT11 (Temperature and Humidity Sensor ) using Node Red

Hi,

 I like to share my first experience connecting Raspberry Pi , DHT11 (Temperature/ Humidity Sensor) using Node Red.

I.Things Needed :

 1. Raspberry Pi 3 Model B+

 2. DHT11 Sensor 

 3. Solderless board

 4. 3 Male to Female Jumper wires.

II.  Circuit Completion

Complete  the circuit has shown below 

III.  Install necessary packages :

a) Download package : http://www.airspayce.com/mikem/bcm2835/bcm2835-1.56.tar.gz

b) tar zxvf bcm2835-1.56.tar.gz

c) Compile process :
         cd bcm2835-1.56

        ./configure

                             
         make

   sudo make check

   sudo make install

d) After completing the installation of the BCM2835 library, we can install the Node-DHT-Sensor library:

                     

sudo npm install node-dht-sensor

   

IV. Node Red Flow 

a) Start Node Red : sudo node-red-start

b) Drag and drop the nodes as shown below and wire them

c) Configure the nodes as shown below : 

 Inject node :

 rpi-dht22  node :

 function node :

 
      var temp = msg.payload;
      var hum  = msg.humidity;

      msg.payload = "The Temperature at Chennai is : " + temp + " C humidity : "  + hum + " %";
      return msg;

Node Red Flow :

[{"id":"815e3de7.d095","type":"function","z":"ca6ebb28.cf4718","name":"function","func":"var temp = msg.payload;\nvar hum  = msg.humidity;\n\nmsg.payload = \"The Temperature at Chennai is : \" + temp + \" C humidity : \"  + hum + \" %\";\n\nreturn msg;","outputs":1,"noerr":0,"x":515,"y":205,"wires":[["9a83148c.58fd18"]]}]


IV. Executing the Node Red Flow 

a) Click Deploy
b) Click the Inject node
c) Output will appear in the debug window

Now , you have successfully got the temperature & humidity from DHT11 Sensor.


Kindly share your comments to improve my posting.