Published September 28, 2020 © GPL3+

IoT based Weather Station using ThingSpeak IoT Analytics

Monitor the Temperature and Humidity on any internet-connected device and also upload that data to ThingSpeak IoT Analytics.

BeginnerFull instructions provided1 hour5,604

IoT based Weather Station using ThingSpeak IoT Analytics

Things used in this project

Hardware components

NodeMCU ESP8266 Breakout Board

DHT11 Temperature & Humidity Sensor (3 pins)

Breadboard (generic)

Male/Female Jumper Wires

Software apps and online services

ThingSpeak API

Google Chrome

Arduino IDE

Hand tools and fabrication machines

USB Cable

Story

Monitor the Temperature and Humidity on any internet-connected device have a Web Browser and also upload that data to the ThingSpeak IoT Analytics Platform.

Project Setup Image

Block Diagram

Prerequisites:

Arduino IDE with ESP8266 add-on installed.

Circuit description and working:

The circuit diagram for monitoring humidity and temperature is shown in the figure below. It is built around the NodeMCU ESP8266-12E board, DHT11 Sensor, and few jumper wires on the solderless breadboard.

Schematic:

Fritzing Sketch

The DHT11 sensor senses humidity and temperature, and sends the information to digital pin D2 of NodeMCU ESP8266-12E board, as shown in the above figure. From NodeMCU, humidity and temperature values are uploaded to the Cloud at regular intervals of time through the NodeMCU ESP8266 Wi-Fi module. From the Cloud, humidity and temperature values can be seen graphically on the ThingSpeak platform from anywhere in the world.

Construction and testing:

Go to the ThingSpeak website on a Web Browser. Thingspeak is an IoT analytics platform but you need to register to use it. After registering, login to your account and Create a new channel with Name, add Description, Temperature as Field1, and Humidity as Field2 (tick the square boxes shown in front of it), you can add Elevation, Latitude & Longitude of the place where you are installing this weather station (tick Show Channel Location) as shown in the figure below. Finally don't forget to tick the Show Status square box & click Save Channel.

Once a new channel is created, go to the API Keys tab, ThingSpeak will generate two API keys, namely, write an API key, and read the API key. Replace the line given below in the program with your write API key:

String apiKey = “NTIM1RXET6YVUVWF“;

Next, substitute const char *ssid and const char *pass with your Wi-Fi name and Wi-Fi password in the two lines given below in the program (code_Weather_Station.ino):

const char *ssid = "DLinkWiFi";

const char *pass = "Pass@123";

The program should be verified with your Wi-Fi setup. It uses the dht library. If the dht library is not present in your Arduino IDE. Go to your PC's File Explorer > Documents > Arduino > libraries. Create a new folder named dht in lower case only, Download the dht.h & dht.cpp files & paste both the files in that dht folder. Close the Arduino IDE.

Open Arduino IDE. Connect the board with a USB cable to the computer. Compile the sketch/program and upload it to NodeMCU Board through Arduino IDE (don't forget to select Board & Port before uploading the sketch). Ensure that the Wi-Fi modem and the Internet connection in your PC/smartphone are working properly. Once sketch uploading is done, it will upload humidity and temperature values on the ThingSpeak platform and you will be able to see it graphically in the Private view window, as shown in the figure below. If you want to change the channel or field name, you can change it from Channel Settings (shown in the figure below).

Finally, your project looks like this image shown below in the Web Browser,

Click here to view my ThingSpeak Channel.

Click here to view my Project Website where I have integrated the whole project to access it with a single click.

Code

Code_Weather_Station

//Weather Station using NodeMCU ESP8266 & Thingspeak IoT Analytics.
// by Pranav Khatale
#include <dht.h> // Include DHT Header file for DHT sensor.
#define dht_apin D2 // Analog Pin sensor is connected to pin D2.
 
dht DHT;// Including library for DHT sensor.

#include <ESP8266WiFi.h>

String apiKey = "NTIM1RXET6YVUVWF";     //  Enter your Write API key from ThingSpeak IoT Analytics Cloud platform.

const char *ssid =  "DLinkWiFi";     // Replace with your Wi-Fi ssid.
const char *pass =  "Pass@123"; // // Replace with your Wi-Fi wpa2 key.
const char *server = "api.thingspeak.com"; //Initializing Server.
WiFiClient client;
 
void setup() 
{
       // Program written in setup will run only once for connecting to Wi-Fi network.
       Serial.begin(115200); // Selecting the baud rate for Serial Communication.
       delay(500);
       // initialize digital pin LED_BUILTIN as an output.
       pinMode(LED_BUILTIN, OUTPUT);
      
       Serial.println("Connecting to ");
       Serial.println(ssid);
 
       WiFi.begin(ssid, pass); // Wi-Fi network searching starts.
 
       while (WiFi.status() != WL_CONNECTED) 
           {
            delay(500);
            Serial.print(".");
           }
       Serial.println("");
       Serial.println("WiFi connected."); //Prints on serial monitor if Wi-Fi gets connected sucessfully.
}
 
void loop() 
{
  DHT.read11(dht_apin); // Reading DHT sensor pin D2's data.
  
      float h = DHT.humidity; // Storing the humidity float value in variable h
      float t = DHT.temperature; // Storing the temperature float value in variable h
      
      if (isnan(h) || isnan(t)) 
         {
          Serial.println("Failed to read from DHT sensor!");
          return;
         }
                 
       if (client.connect(server,80))   // "184.106.153.149" or api.thingspeak.com
          {                  
           String postStr = apiKey;
           postStr +="&field1=";
           postStr += String(t);
           postStr +="&field2=";
           postStr += String(h);
           postStr += "\r\n\r\n";
 
           client.print("POST /update HTTP/1.1\n");
           client.print("Host: api.thingspeak.com\n");
           client.print("Connection: close\n");
           client.print("X-THINGSPEAKAPIKEY: "+apiKey+"\n");
           client.print("Content-Type: application/x-www-form-urlencoded\n");
           client.print("Content-Length: ");
           client.print(postStr.length());
           client.print("\n\n");
           client.print(postStr);

           // Printing DHT Sensor's Humidity & Temperature on Serial Monitor.
           Serial.print("Temperature: "); 
           Serial.print(t);
           Serial.print(" C, Humidity: ");
           Serial.print(h);
           Serial.println("% ||| Data sent to Thingspeak IoT Analytics Cloud platform.");
          }
          client.stop();
          Serial.println("Waiting..."); // Waiting for new data to be sensed by DHT Sensor.
  
  // thingspeak needs minimum 15 sec delay between on Cloud console updates for free subscription.
  digitalWrite(LED_BUILTIN, HIGH); 
  delay(1000);
  digitalWrite(LED_BUILTIN, LOW);
}