Controlling an LED Light with PC using ESP8266 based HAN and HiveMQ Broker: IOT Part 20

Fig. 7: Table listing the pin configuration of IC CP2102

 ###



 //Program to

 /*

 * File Name - ESP8266_with_PC_client.ino

 * Created: 3/20/2017 11:02:11 AM
 
* Main Source Code for PC and ESP8266 clients communication with HiveMQ broker

 */


 /*

 * Output Pins of the ESP8266

 *GPIO02 - ledPin

 */


 //Include libraries

 #include //Include the library for WiFI Initialization

 #include //Include the library for MQTT pubsub protocol


 // WIFI setup

 const char* ssid = "Replace it with the SSID of the Wi-Fi Network"; //SSID of the WIFI network

 const char* password = "Replace it with the password of the Wi-Fi Network"; //Password of the WIFI network


 //The broker or server domain name

 const char* mqtt_server = "broker.mqtt-dashboard.com";


 // Create an ESP8266 WiFiClient class to connect to the MQTT server.

 WiFiClient espClient;

 //create the MQTT client objects

 PubSubClient client(espClient);


 void setup {

 pinMode(2,OUTPUT); //configure the led pin as OUTPUT
 
Serial.begin(115200); //Set the baudrate of ESP8266 to show the process on serial monitor

 setup_wifi; //Initialize the Wifi



 //By setting server and messgae callback function, the client is ready to use

 //& 1883 is the listener port for the broker

 client.setServer(mqtt_server, 1883);

 client.setCallback(Received_Message);

 }


 /*

 * Function Name = setup_wifi

 *To establish the WIFI connection with ESP8266

 */

 void setup_wifi {


 delay(10);

 // We start by connecting to a WiFi network

 Serial.println;

 Serial.print("Connecting to ");

 Serial.println(ssid);

 //Connect to the WIFI

 WiFi.begin(ssid, password);

 // Wait until the connection has been confirmed before continuing

 while (WiFi.status != WL_CONNECTED) {

 delay(500);

 Serial.print(".");

 }


 Serial.println("");

 Serial.println("WiFi connected");

 Serial.println("IP address: ");

 Serial.println(WiFi.localIP );

 }


 /*

 * Function name = Received_message
 
* Client receives the message and functions accordingly

 * Input parameter = Topic, Payload and message length

 * Output parameter = void

 */

 void Received_Message(char* topic, byte* payload, unsigned int length) {

 Serial.print("Message arrived (");

 Serial.print(topic);

 Serial.print() ");

 for (int i = 0; i < length; i++) {

 Serial.print((char)payload(i));

 }



 // Handle the message we received

 // Here, we are only looking at the characters of the received message

 // If it is on, turn the led will be on.

 // If it is off, turn the led will be off.

 if((char)payload(0) == 'o' && (char)payload(1) == 'n') //on

 digitalWrite(2,HIGH);

 else if((char)payload(0) == 'o' && (char)payload(1) == 'f' && (char)payload(2) == 'f') //off

 digitalWrite(2,LOW);



 Serial.println;

 }


 /*

 * Function Name = Reconnect

 * To establish the connection of ESP8266 with MQTT broker

 * and Will publish and subscribe to the topic

 */

 void reconnect {

 // Loop until we're reconnected
 
while (!client.connected ) {

 Serial.print("Attempting MQTT connection...");

 // Attempt to connect

 if (client.connect("ESP8266Client")) {

 Serial.println("connected");

 // Once connected, publish an announcement...

 client.publish("ESP8266/connection status", "Connected!");

 // ... and resubscribe

 client.subscribe("ESP8266/LED status");

 } else {

 Serial.print("failed, rc=");

 Serial.print(client.state );

 Serial.println(" try again in 5 seconds");

 // Wait 5 seconds before retrying

 delay(5000);

 }

 }

 }


 void loop {

 //When ESP8266 client will be connected to the broker,

 //then call the function reconnect and publish and subscribe the data from broker.

 if (!client.connected ) {

 reconnect;

 }

 client.loop;

 }


 ###