TEMPERATURE DATA TO THINGSPEAK

ThingSpeak is an IoT platform that helps us to collect sensor values from various nodes like we use NodeMcu and puts them in a graphical manner and provides many options like sending us email or SMS when if a certain condition is met.

In this tutorial, How to send DHT11 (Temperature and Humidity Sensor) data to Thingspeak.

CONNECTIONS :

  ARDUINO           DHT11
  5v          -        5v
  Gnd         -        Gnd
  D4          -        Data pin

PROCEDURE :

Create a account in Thingspeak.
Click Newchannel and create a channel with two fields and save channel.
Then in the tab API Keys we will find the Channel ID, Write api Key .
Download the Thingspeak library from https://github.com/mathworks/thingspeak-arduino.
Download the Dht library from https://github.com/adafruit/DHT-sensor-library.
While compling if it shows Adafruit_Sensor.h missing download it from https://github.com/adafruit/Adafruit_Sensor.
and paste it in the library folder of Arduino(It will be in C:\Program Files (x86)\Arduino\libraries).

Program for NodeMcu is given below

 #include <DHT.h> 
#include <ESP8266WiFi.h> 
#include <WiFiClient.h> 
#include <ThingSpeak.h>
 #define DHTPIN D4
 #define DHTTYPE DHT11 
 DHT dht(DHTPIN, DHTTYPE); 
 const char* ssid = "Username"; //Change with your Username
 const char* password = "Password"; // Change with your Password
 WiFiClient client; 
 unsigned long myChannelNumber = ChannelId; //Your channel Id
 const char * myWriteAPIKey = "Your Wirite api key"; //Write api key
 uint8_t temperature, humidity; 
 void setup() 
 { 
 Serial.begin(115200); 
 dht.begin(); 
 delay(10);
 // Connect to WiFi network 
 Serial.println(); 
 Serial.println(); 
 Serial.print("Connecting to "); 
 Serial.println(ssid); 
 WiFi.begin(ssid, password); 
 while (WiFi.status() != WL_CONNECTED) 
 { 
 delay(500); 
 Serial.print("."); 
 } 
 Serial.println(""); 
 Serial.println("WiFi connected"); 
 // Print the IP address 
 Serial.println(WiFi.localIP()); 
 ThingSpeak.begin(client); 
 } 
 void loop() 
 { 
 static boolean data_state = false; 
 temperature = dht.readTemperature(); 
 humidity = dht.readHumidity(); 
 Serial.print("Temperature Value is :"); 
 Serial.print(temperature); 
 Serial.println("C"); 
 Serial.print("Humidity Value is :"); 
 Serial.print(humidity); 
 Serial.println("%"); 
 // Write to ThingSpeak. There are up to 8 fields in a channel, allowing you to store up to 8 different 
 // pieces of information in a channel. Here, we write to field 1. 
 if( data_state ) 
 { 
 ThingSpeak.writeField(myChannelNumber, 1, temperature, myWriteAPIKey); 
 data_state = false; 
 } 
 else 
 { 
 ThingSpeak.writeField(myChannelNumber, 2, humidity, myWriteAPIKey); 
 data_state = true; 
 } 
 delay(30000); // ThingSpeak will only accept updates every 15 seconds. 
 }

const char* ssid = "Username";
const char* password = "Password";

Change the above lines with your Wi-Fi Username and Password.
Make sure that you select the correct COM port.

unsigned long myChannelNumber = ChannelId; 
 const char * myWriteAPIKey = "Your Wirite api key";

Change it with your Channel Id and Write api key.
Then upload the program into NodeMcu
Make sure that you provide a good Internet connection using the Wi-Fi.

See my vedio below to get a clear idea

ThingSpeak will accecpt values only after a break of 15 seconds.

Data will be displayed like a graph shown below

ANDROID :

Download Thingviewfree app from play store and install it.
To see the channel you have to make the channel as public.
To do so go to sharing tab and check the Share channel view with everyone in Channel sharing settings.
Then open the app and follow the slideshow given below