Build a Device Integration Block

/**********************************************************************************

 * ESP8266 Remote Temperature and Fire Status Monitoring and Buzzer Control 

 * from ThingSpeak IoT Platform

 * Add libraries: 

 *   - DHT sensor library by Adafruit v1.3.6

 *   - Adafruit unified sensor by Adafruit 1.0.3

 * Compile for board: NodeMCU 1.0 (ESP 12E Module)

 * Create an account on ThingSpeak IoT Platform (https://thingspeak.com)

 * Create a private channel on ThingSpeak

 *********************************************************************************/

#include <ESP8266WiFi.h>

#include <ESP8266HTTPClient.h>

#include "DHT.h"

static char celsiusTemp[7];

// DHT Sensor type

#define DHTTYPE DHT11 // Change it to DHT11 or DHT22 depending on the sensor type used

// Device Pins

#define TempHumidityPin D1 // Change it to the NodeMCU pin to which the temp sensor is connected

#define FirePin D2         // Change it to the NodeMCU pin to which the fire sensor is connected 

#define BuzzerPin D3       // Change it to the NodeMCU pin to which the buzzer device is connected  

// Wi-Fi Settings

const char* ssid = "ABCDEF"; // Add your wireless network name (SSID)

const char* password = "1234567890"; // Add your Wi-Fi network password

WiFiClient client;

// ThingSpeak Settings

const int channelID = 999999;            // Add your ThingSpeak Channel ID

String writeAPIKey = "XXXXXXXXXXXXXXXX"; // Add Write API key for your ThingSpeak Channel

const char* server = "api.thingspeak.com";

const int postingInterval = 5 * 1000; // post data every 5 seconds

// Variable Setup

long lastConnectionTime = 0;

String fireStatusString = "Not Detected";

// Initialize the program

void setup() {  

  pinMode(BuzzerPin, OUTPUT);

  digitalWrite(BuzzerPin, LOW);

  Serial.begin(9600);

  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {

    delay(500);

  }

}

// Read temperature value from the DHT11 sensor

String getTemperatureData() {   

    // Initialize DHT sensor

    DHT dht(TempHumidityPin, DHTTYPE);

    dht.begin();

    // Read temperature as Celsius (the default)

    float t = dht.readTemperature();

    return ((String)t);

}

// Read humidity value from the DHT11 sensor

String getHumidityData() {   

    // Initialize DHT sensor

    DHT dht(TempHumidityPin, DHTTYPE);

    dht.begin();

    // Read temperature as Celsius (the default)

    float h = dht.readHumidity();

    return ((String)h);

}

// Read fire status from Flame Sensor

int getFireStatus() {

  int fireStatus = digitalRead(FirePin);

  if (fireStatus == LOW) {

    // LOW means fire detected (depends on sensor module)

    Serial.println("Fire Detected!");

  } else {

    Serial.println("No Fire");

  }

  return fireStatus;

  delay(500); // Small delay for readability

}

// Process Buzzer Turn on / Turn off request 

void checkBuzzerControlTalkBack()

{

  String talkBackAPIKey = "ZZZZZZZZZZZZZZZZ";

  String talkBackID = "888888";

  Serial.println("Inside checkBuzzerControlTalkBack");

  //HttpClient client;

  HTTPClient http; 

  String thingSpeakAPI = "api.thingspeak.com";

  char charIn;

  String talkBackURL =  "http://" + thingSpeakAPI + "/talkbacks/" + talkBackID + "/commands/execute?api_key=" + talkBackAPIKey;

  // Make a HTTP GET request to the TalkBack API:

  http.begin(talkBackURL); 

  int httpCode = http.GET(); 

  if (httpCode > 0) { //Check the returning code

      String talkBackCommand = http.getString();   //Get the request response payload

      Serial.println("TalkbackCommand= ");

      Serial.println(talkBackCommand.c_str());                     //Print the response payload

      http.end();   //Close connection

      if (!strcmp(talkBackCommand.c_str(), "TURN_ON")) {  

           Serial.println("Turning on Buzzer for 5 seconds");

           digitalWrite(BuzzerPin, HIGH);

      } 

      else if (!strcmp(talkBackCommand.c_str(), "TURN_OFF")) {  

           Serial.println("Turning off Buzzer");

           digitalWrite(BuzzerPin, LOW);

      }

      else {

         Serial.println("Unknown command");

      }

      Serial.flush(); 

      delay(1000);

  }

}

// Package the HTTP message to be sent to ThingSpeak IoT Platform

void postHTTPMessage(String body) {

   client.println("POST /update HTTP/1.1");

   client.println("Host: api.thingspeak.com");

   client.println("User-Agent: ESP8266 (nothans)/1.0");

   client.println("Connection: close");

   client.println("X-THINGSPEAKAPIKEY: " + writeAPIKey);

   client.println("Content-Type: application/x-www-form-urlencoded");

   client.println("Content-Length: " + String(body.length()));

   client.println("");

   client.print(body);

}

// Main program looping forever

void loop() {

   if (client.connect(server, 80)) {

       String temperature = getTemperatureData();

       // If temperature data is not valid, consider temperature value as 0

       if (!strcmp(temperature.c_str(), "NaN") || !strcmp(temperature.c_str(), "nan")) {

          temperature = "0"; 

       }

       delay(1000);

       Serial.print("Temperature: ");

       Serial.print(temperature); 

       Serial.println(" degree Celsius");

       String humidity = getHumidityData();

       // If humidity data is not valid, consider humidity value as 0

       if (!strcmp(humidity.c_str(), "NaN") || !strcmp(humidity.c_str(), "nan")) {

          humidity = "0"; 

       }

       delay(1000);

       Serial.print("Humidity: ");

       Serial.print(humidity); 

       Serial.println(" %");

       int fireStatus = getFireStatus();

       Serial.println("Fire Status:");

       Serial.print(fireStatus);

       // Construct API request body

       String body = "field1=";

           body += String(temperature);

           body += "&";

           body += "field2=";

           body += String(humidity);

           body += "&";

           body += "field6=";

           body += String(fireStatus);

       postHTTPMessage(body);

   }

   client.stop();

   // wait and then post again

   delay(postingInterval);     

   // Check ThingSpeak for TalkBack Commands

   checkBuzzerControlTalkBack();

   delay(1000);

}