Notes

/***************************************************
Adafruit MQTT Library ESP8266 Example

Must use ESP8266 Arduino from:
https://github.com/esp8266/Arduino

Works great with Adafruit's Huzzah ESP board & Feather
----> https://www.adafruit.com/product/2471
----> https://www.adafruit.com/products/2821

Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Tony DiCola for Adafruit Industries.
MIT license, all text above must be included in any redistribution
****************************************************/
#include <ESP8266WiFi.h>
#include "Adafruit_MQTT.h"
#include "Adafruit_MQTT_Client.h"

/************************* WiFi Access Point *********************************/

#define WLAN_SSID "Obaidur"
#define WLAN_PASS "tubelight"

/************************* Adafruit.io Setup *********************************/

#define AIO_SERVER "io.adafruit.com"
#define AIO_SERVERPORT 1883 // use 8883 for SSL
#define AIO_USERNAME "TRbulbul"
#define AIO_KEY "aio_LXJF23nQx2uF5BZjOVPACbWrDD6f"
/************ Global State (you don't need to change this!) ******************/

// Create an ESP8266 WiFiClient class to connect to the MQTT server.
WiFiClient client;
// or... use WiFiClientSecure for SSL
//WiFiClientSecure client;

// Setup the MQTT client class by passing in the WiFi client and MQTT server and login details.
Adafruit_MQTT_Client mqtt(&client, AIO_SERVER, AIO_SERVERPORT, AIO_USERNAME, AIO_KEY);

/****************************** Feeds ***************************************/

// Setup a feed called 'photocell' for publishing.
// Notice MQTT paths for AIO follow the form: <username>/feeds/<feedname>
Adafruit_MQTT_Publish photocell = Adafruit_MQTT_Publish(&mqtt, AIO_USERNAME "/feeds/GasSensor");

// Setup a feed called 'onoff' for subscribing to changes.
//Adafruit_MQTT_Subscribe onoffbutton = Adafruit_MQTT_Subscribe(&mqtt, AIO_USERNAME "/feeds/onoff");

/*************************** Sketch Code ************************************/

// Bug workaround for Arduino 1.6.6, it seems to need a function declaration
// for some reason (only affects ESP8266, likely an arduino-builder bug).

int buzzer = D6;
int smoke_detector = A0;
int safety_lim = 350;//Sets smoke density safe limit
int LED = D4;
int rstButton = D3;

void MQTT_connect();

void setup() {

pinMode(buzzer, OUTPUT);
pinMode(smoke_detector, INPUT);
pinMode(LED, OUTPUT);
pinMode(rstButton, INPUT);
digitalWrite(LED,LOW);

Serial.begin(115200);
delay(10);


Serial.println(F("Adafruit MQTT demo"));

// Connect to WiFi access point.
Serial.println(); Serial.println();
Serial.print("Connecting to ");
Serial.println(WLAN_SSID);

WiFi.begin(WLAN_SSID, WLAN_PASS);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println();

Serial.println("WiFi connected");
Serial.println("IP address: "); Serial.println(WiFi.localIP());

// Setup MQTT subscription for onoff feed.
//mqtt.subscribe(&onoffbutton);
}

uint32_t x=0;

void loop() {
// Ensure the connection to the MQTT server is alive (this will make the first
// connection and automatically reconnect when disconnected). See the MQTT_connect
// function definition further below.
MQTT_connect();

bool GasDetected = false;
int sensor_read = analogRead(smoke_detector);
int rstall = digitalRead(rstButton);
Serial.print(sensor_read);
if (sensor_read > safety_lim)
// Checks if reading is beyond safety limit
{

digitalWrite(buzzer, HIGH);
digitalWrite(LED, HIGH);
GasDetected = true;
}
else
{
digitalWrite(buzzer, LOW);
GasDetected = false;

}
if(GasDetected){
Serial.print("Gas detected...!n");
sendinFunction(sensor_read);
}
else if(rstall == 1){
digitalWrite(LED, LOW);
}
else{
Serial.print(sensor_read);
Serial.print("n");
}
delay(50);



// ping the server to keep the mqtt connection alive
// NOT required if you are publishing once every KEEPALIVE seconds
/*
if(! mqtt.ping()) {
mqtt.disconnect();
}
*/
}

// Function to connect and reconnect as necessary to the MQTT server.
// Should be called in the loop function and it will take care if connecting.
void MQTT_connect() {
int8_t ret;

// Stop if already connected.
if (mqtt.connected()) {
return;
}

Serial.print("Connecting to MQTT... ");

uint8_t retries = 3;
while ((ret = mqtt.connect()) != 0) { // connect will return 0 for connected
Serial.println(mqtt.connectErrorString(ret));
Serial.println("Retrying MQTT connection in 5 seconds...");
mqtt.disconnect();
delay(5000); // wait 5 seconds
retries--;
if (retries == 0) {
// basically die and wait for WDT to reset me
while (1);
}
}
Serial.println("MQTT Connected!");
}


void sendinFunction(int analogVlue){
int AnalogRead = analogVlue;
Serial.print(F("nSending photocell val "));
Serial.print(x);
Serial.print("...");
if (! photocell.publish(AnalogRead)) {
Serial.println(F("Failed"));
} else {
Serial.println(F("OK!"));
}
delay(5000);

}